BROMPTON GEARS_2_

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					      TABLE OF CONTENTS
USER INSTRUCTIONS & HELPS
       Setting Up Your Screen for FULL VIEW
       What you can do with the Brompton Gear Charts
       Understanding Bicycle Gears & Nomenclature
       Brompton's Offerings for Gearing Solutions

BROMPTON GEARING CHARTS
     SRAM 3 Speed with/without Front Derailleur Option



       SRAM 3 Speed with/without Mountain Drive Option



       SRAM 6 Speed Rear Derailleur with Front Derailleur Option



       SRAM 6 Speed Rear Derailleur with/without Mountain Drive Option



       STURMEY 3 Speed with/without Mountain Drive Option



       STURMEY 5 Speed with/without Mountain Drive Option



       STURMEY 5 Speed with/without Front Derailleur Option



GEARING STANDARDS FOR USA BROMPTON FOLDING BIKE


                                                                         d
                                                                      CLICK on the PAGE
   TABLE OF CONTENTS                                                   NUMBER below to
                                                                          SELECT
ER INSTRUCTIONS & HELPS
     Setting Up Your Screen for FULL VIEW                                 Page 2
     What you can do with the Brompton Gear Charts                        Page 3
     Understanding Bicycle Gears & Nomenclature                           Page 4
     Brompton's Offerings for Gearing Solutions                           Page 5

OMPTON GEARING CHARTS
   SRAM 3 Speed with/without Front Derailleur Option
         Example & explanation of Gear chart                              Page 6
         ACTUAL GEAR CHART                                                Page 7
    SRAM 3 Speed with/without Mountain Drive Option
          Example & explanation of Gear chart                             Page 8
          ACTUAL GEAR CHART                                               Page 9
    SRAM 6 Speed Rear Derailleur with Front Derailleur Option
          Example & explanation of Gear chart                             Page 10
          ACTUAL GEAR CHART                                               Page 11
    SRAM 6 Speed Rear Derailleur with/without Mountain Drive Option
          Example & explanation of Gear chart                             Page 12
          ACTUAL GEAR CHART                                               Page 13
    STURMEY 3 Speed with/without Mountain Drive Option
         Example & explanation of Gear chart                              Page 14
         ACTUAL GEAR CHART                                                Page 15
    STURMEY 5 Speed with/without Mountain Drive Option
         Example & explanation of Gear chart                              Page 16
         ACTUAL GEAR CHART                                                Page 17
    STURMEY 5 Speed with/without Front Derailleur Option
         Example & explanation of Gear chart                              Page 18
         ACTUAL GEAR CHART                                                Page 19

ARING STANDARDS FOR USA BROMPTON FOLDING BIKE                             Page 20


                                                                          design & program by: ULTIMATE Solutions Inc.
y: ULTIMATE Solutions Inc.
SETTING UP YOUR SCREEN FOR FULL VIEW OF THE BROMPTON GEAR CHARTS
          We want to eliminate all toolbars at the top and bottom of your screen that will interfere with the viewing of the Gear Charts


            EXAMPLE OF YOUR SCREEN AT THE TOP
                                                                             At the top of your screen locate the VIEW Menu and follow the instructions below
                                                                                  (note: you will have to remove each existing Check Mark one at a time)


                                                                             Under the VIEW Menu

                                                                                                     Uncheck/Deselect/Remove Check Marks
                                                                                                     from "Formula Bar" and "Status Bar" if
                                                                                                     any check marks appear on your menu.

                                                                             Under the VIEW Menu


                                                                                         TOOLBARS Sub-menu

                                                                                                     Uncheck/Deselect/Remove Check Marks
                                                                                                     from ALL items checked on your sub-menu

                                                                             Under the VIEW Menu

                                                                                                     Select




                                                                                          CLICK HERE to
                                                                                          Return to The
                                                                                             Table of
                                                                                            Contents

When set correctly, you should ONLY have one (1) Menu bar at the top.

                                                                                                                                                           Page 2
        WHAT YOU CAN DO WITH THE BROMPTON GEAR CHARTS

COMPARISIONS
     Within each gear chart, you can make up to four (4) sets of Gear Ratios for comparing one to the other.

INTERACTIVE
    Most people will be able to create these comparisons on-line; however, you may also download the chart
    workbook and do the comparsions off-line as well.

DOWNLOADING
   Elsewhere within this website, you will have an option to DOWNLOAD the Gear Chart Workbook
   This is a special constructed Excel Workbook; however, it may be converted to other Spreadsheet
   Workbooks such as Corel and Lotus.

PRINTING
    Each of the charts has been preset to print just the Comparison results by simply selecting PRINT
    under the FILE MENU at the top of your screen. To correct or change the printing, follow these
    instructions:
          Highlight the area of the chart that you want to print
          Under the FILE MENU ...… select-> PRINT AREA and select -> SET AREA
          Under the FILE MENU ...… select-> PAGE SET UP
                 Under Orientation … select -> LANDSCAPE
                 Under Scaling ….…. select -> Fit to 1 page wide and 1 tall



                       CLICK HERE TO RETURN TO THE TABLE OF CONTENTS




                                                                                                               Page 3
                       Understanding Bicycle Gears & Nomenclature
                                     The first bicycles did not have gears. As in the one at the left, all were direct drive. Each revolution
                                     of the rider's feet turned the drive wheel once. Therefore the ratio of the rider's revolutions and the
                                     the drive wheel revolutions was 1:1.

                                     In comparing one bicycle to another, the reference was the diameter of the drive wheel. The bicycle
                                     to the left has a 54" (inch) drive wheel. A bicycle with a larger drive wheel would go farther (or faster)
                                     with each turn of the drive wheel and a bicycle with a smaller drive wheel would travel less distance
                                     (or go slower) than the larger-wheel bike.

                                     This measurement of the drive wheel diameter became the standard measurement of bikes regarding
                                     its relationship to speed and distance.

                                     Therefore people would refer to their bike as having a 54", a 50", a 48", a 46" wheel, etc. Each bike
                                     however ONLY had one big wheel size, which had the advantage of going farther but harder to pump.




                                     Then came the "Safety Bike", called such because it put the rider lower to the ground. In the case
                                     of a single-speed bike, the relationship between the "pedal wheel sprocket" (chain ring) and the
                                     drive wheel sprocket (rear spocket) was changed from 1:1 ratio to a 2:1 ratio. Meaning that each time
                                     the rider turned one revolution with his feet, the drive wheel in the rear, turned two times, or twice.

                                     In this case with an "actual wheel diameter" of 27" (inches) the 2:1 gear ratio made the drive wheel
                                     the equivalent of twice that, or 54" (inchs), the same wheel diameter size as the Big Wheel Bike
                                     above, but with the safety of being lower to the ground in case of a fall.

                                     From there, bikes came onto the market with multiple gears, each having a different ratio and each
                                     resulting in a different EQUIVALENT DRIVE WHEEL SIZE, allowing the rider to select the best wheel
                                     size for the condition of the road he/she was traveling.


  When discussing a bicycle's gears, we refer to the RESULTING EQUIVALENT WHEEL SIZE it produces. Such as a 3-Speed Bike
having 48", 66", 90" (inch) wheel sizes! And in this example, in high gear, the rider would have a bike with a Resulting Equivalent Drive
Wheel Size of nearly 8 feet (90"). The charts contained herein will compute all the Brompton Wheel Sizes with the gear ratios you select.


                                   CLICK HERE TO RETURN TO THE TABLE OF CONTENTS


                                                                                                                                                  Page 4
             BROMPTON'S OFFERINGS FOR GEARING SOLUTIONS
                                                                                          Number
                     GENERAL GEAR COMBINATION OFFERINGS                                   of Gears
1   SINGLE FRONT CHAIN RING and 3 SPEED REAR HUB INTERNAL GEARS                 ………..        3
    MOUNTAIN DRIVE SINGLE FRONT CHAIN RING and 3 SPEED REAR HUB INTERNAL
2
    GEARS                                                                       ………..        6
3   SINGLE FRONT CHAIN RING and 5 SPEED REAR HUB INTERNAL GEARS                 ………….        5
    MOUNTAIN DRIVE SINGLE FRONT CHAIN RING and 5 SPEED REAR HUB INTERNAL
4
    GEARING                                                                     …………..       10
5   DUAL FRONT CHAIN RING DERAILLEUR and 3 SPEED REAR HUB INTERNAL GEARS        …………         6
6   DUAL FRONT CHAIN RING DERAILLEUR and 5 SPEED REAR HUB INTERNAL GEARS        ………..        10
    SINGLE FRONT CHAIN RING and DUAL REAR SPROCKET DERAILLEUR with 3 SPEED
7
    REAR HUB INTERNAL GEARS                                                     ………..        6
    MOUNTAIN DRIVE SINGLE FRONT CHAIN RING and DUAL REAR SPROCKET DERAILLEUR
8
    with 3 SPEED REAR HUB INTERNAL GEARS                                     ………..           12
    DUAL FRONT CHAIN RING DERAILLEUR and DUAL REAR SPROCKET DERAILLEUR with 3
9
    SPEED REAR HUB INTERNAL GEARS                                               ………..        12
                  CHAIN RING & SPROCKET OFFERINGS & OPTIONS                               In Stock
A   SINGLE FRONT CHAIN RING OPTIONS: ……………………………………..…………………                             44/50 teeth
B   SINGLE REAR SINGLE SPROCKET OPTIONS: …………………………………………………                        13/14/15 teeth
C DUAL FRONT CHAIN RING OFFERING: ………………………………………………………….                               39 & 53 teeth
D DUAL REAR SPROCKET OFFERING …………………...……….………………………………                                13 & 15 teeth
C MOUNTAIN DRIVE CHAIN RING OFFERING …………………........…………………………..                          54 teeth


                          CLICK HERE TO RETURN TO THE TABLE OF CONTENTS




                                                                                                        Page 5
                   EXAMPLE & EXPLANATION OF CHART WITH FRONT DERAILLEUR OPTION

                                                             Go back to TABLE OF CONTENTS                       CLICK HERE

                                                           Go to ACTUAL DATA ENTRY CHART                        CLICK HERE




               BROMPTON SRAM 3 SPEED GEAR CALCULATIONS with the FRONT DERAILLEUR OPTION
                                                   Standard                      Notes Sprocket ratios other than the Brompton Standard ratio
              Brompton Standard Wheel Size       16.375 inches                   The "Actual" physical wheel diameter size
   Data                      REAR Sprocket            13     teeth               The number of teeth in the Rear sprocket (You will be allowed to vary this)
   Entry                  SMALL Chain Ring            39     teeth               The number of teeth in the Small Front Chain Ring (You will be allowed to vary this)
   Area                   LARGE Chain Ring            53     teeth               The number of teeth in the Large Front Chain Ring (You will be allowed to vary this)

        Small Chain Resulting Sprocket Ratio       3.000 to 1                    The resulting sprocket ratio with the SMALL chain ring engaged
        Large Chain Resulting Sprocket Ratio       4.077 to 1                    The resulting sprocket ratio with the LARGE chain ring engaged
Resulting Small Chain Direct Drive Wheel Size       49.1    inches               The resulting WHEEL SIZE in Direct Drive with the SMALL chain ring engaged
Resulting Large Chain Direct Drive Wheel Size       66.8    inches               The resulting WHEEL SIZE in Direct Drive with the LARGE chain ring engaged

         REAR HUB GEAR SELECTION                Resulting Wheel Size
With SMALL Chain Ring Engaged … 1st gear            35.9    inches      ##         RESULTING WHEEL                    With Rear Hub 1st gear engaged
                               2nd gear             49.1    inches      ##       SIZES with SMALL Chain               With Rear Hub 2nd gear engaged (direct drive)
                                3rd gear            66.8    inches      ##            Ring Engaged                    With Rear Hub 3rd gear engaged
With LARGE Chain Ring Engaged … 1st gear            48.7    inches      ##         RESULTING WHEEL                    With Rear Hub 1st gear engaged
                               2nd gear             66.8    inches      ##       SIZES with LARGE Chain               With Rear Hub 2nd gear engaged (direct drive)
                                3rd gear            90.8    inches      ##            Ring Engaged                    With Rear Hub 3rd gear engaged



       To CLEAR Screen of Messages:                                    CLICK HERE to CLEAR HELP MESSAGES and NOTES



                                                                                                                                                    Page 6
                USER INSTRUCTIONS:              The BLUE entry points         Blue      below are where you may enter combinations
                                                of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                                and the chart will compute the resulting Wheel Sizes for the different Gear Settings.
                                                                                                                                                             CLICK HERE
        Mouse or Keyboard TAB key:              You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                 to Return to
                                                which cycle you through the various data entry points or by MOUSE CLICKING the entry                           Table of
                                                point allowing you to enter different spocket teeth values for comparison combinations.                        Contents

             HELP Messages & Notes:             On the right side of the chart, you will see the words HELP and NOTE. MOUSE
                                                CLICK on these words for the Help or Note message associated with that area.



   BROMPTON SRAM 3 SPEED GEAR CALCULATIONS with the FRONT DERAILLEUR OPTION
                                                     Standard                  7% Reduction                13% Reduction                 Standard
              Brompton Standard Wheel Size         16.375 inches               16.375 inches               16.375 inches               16.375 inches             Note
   Data                      REAR Sprocket             13     teeth                 14     teeth                15     teeth                13     teeth         Help
   Entry                  SMALL Chain Ring             39     teeth                 39     teeth                39     teeth                39     teeth         Help
   Area                   LARGE Chain Ring             53     teeth                 53     teeth                53     teeth                53     teeth         Help
        Small Chain Resulting Sprocket Ratio        3.000 to 1                   2.786 to 1                  2.600 to 1                  3.000 to 1
                                                                                                                                                                 Note
        Large Chain Resulting Sprocket Ratio        4.077 to 1                   3.786 to 1                  3.533 to 1                  4.077 to 1
Resulting Small Chain Direct Drive Wheel Size        49.1    inches               45.6    inches              42.6    inches              49.1    inches
                                                                                                                                                                 Note
Resulting Large Chain Direct Drive Wheel Size        66.8    inches               62.0    inches              57.9    inches              66.8    inches
                                                                                                                                                             Resulting % of
         REAR HUB GEAR SELECTION                 Resulting Wheel Size         Resulting Wheel Size        Resulting Wheel Size        Resulting Wheel Size    Direct drive
With SMALL Chain Ring Engaged … 1st gear             35.9    inches      ##       33.3    inches     ##       31.1    inches     ##       35.9    inches       73.00%
                               2nd gear              49.1    inches      ##       45.6    inches     ##       42.6    inches     ##       49.1    inches      100.00%         Note
                                3rd gear             66.8    inches      ##       62.0    inches     ##       57.9    inches     ##       66.8    inches      136.00%
With LARGE Chain Ring Engaged … 1st gear             48.7    inches      ##       45.3    inches     ##       42.2    inches     ##       48.7    inches       73.00%
                               2nd gear              66.8    inches      ##       62.0    inches     ##       57.9    inches     ##       66.8    inches      100.00%         Note
                                3rd gear             90.8    inches      ##       84.3    inches     ##       78.7    inches     ##       90.8    inches      136.00%



       To CLEAR Screen of Messages:                                     CLICK HERE to CLEAR HELP MESSAGES and NOTES


                                                                                                                                                               Page 7
             EXAMPLE & EXPLANATION OF CHART with and without the MOUNTAIN DRIVE OPTION


                                                           Go back to TABLE OF CONTENTS                        CLICK HERE

                                                         Go to ACTUAL DATA ENTRY CHART                         CLICK HERE




       BROMPTON SRAM 3 SPEED GEAR CALCULATIONS with and without the MOUNTAIN DRIVE OPTION
                                                 Standard                      Notes Sprocket ratios other than the Brompton Standard ratio
            Brompton Standard Wheel Size       16.375 inches                   The "Actual" physical wheel diameter size
  Data                                                                         The number of teeth in the Rear sprocket (You will be allowed to vary this)
                             Rear Sprocket          13     teeth
  Entry                   Front Chain Ring          50     teeth               The number of teeth in the Front Chain Ring (You will be allowed to vary this
  Area
                  Resulting Sprocket Ratio       3.846 to 1                    The resulting sprocket ratio
          Resulting Direct Drive Wheel Size       63.0    inches               The resulting WHEEL SIZE in Direct Drive

         REAR HUB GEAR SELECTION              Resulting Wheel Size
   With Mountain Drive Engaged … 1st gear         18.4    inches      ##         RESULTING WHEEL                    With Rear Hub 1st gear engaged
                                 2nd gear         25.2    inches      ##         SIZES with Mountain                With Rear Hub 2nd gear engaged (dir
                                  3rd gear        34.3    inches      ##            Drive Engaged                   With Rear Hub 3rd gear engaged
Without Mountain Drive Engaged …. 1st gear        46.0    inches      ##          RESULTING WHEEL                     NOTE: If you do not own the Mountain Drive
                                 2nd gear         63.0    inches      ##         SIZES Mountain Drive                 Option, these are the ONLY Resulting wheel
                                  3rd gear        85.7    inches      ##             Disengaged                                           sizes.




      To CLEAR Screen of Messages:                                   CLICK HERE to CLEAR HELP MESSAGES and NOTES
E OPTION




UNTAIN DRIVE OPTION
ompton Standard ratio


et (You will be allowed to vary this)
Ring (You will be allowed to vary this)




ith Rear Hub 1st gear engaged
ith Rear Hub 2nd gear engaged (direct drive)
ith Rear Hub 3rd gear engaged
NOTE: If you do not own the Mountain Drive
Option, these are the ONLY Resulting wheel
                    sizes.




and NOTES
Page 8
              USER INSTRUCTIONS:              The BLUE entry points         Blue      below are where you may enter combinations
                                              of different values for the number of teeth on the CHAIN RING and REAR sprockets.
                                              and the chart will compute the resulting Wheel Sizes for the different Gear Settings.
                                                                                                                                                          CLICK HERE
       Mouse or Keyboard TAB key:             You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                to Return to
                                              which cycle you through the various data entry points or by MOUSE CLICKING the entry                          Table of
                                              point allowing you to enter different sprocket teeth values for comparison combinations.                      Contents

           HELP Messages & Notes:             On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK
                                              on these words for the Help or Note message associated with that area.


BROMPTON SRAM 3 SPEED GEAR CALCULATIONS with & without MOUNTAIN DRIVE OPTION
                                                   Standard                 7% Reduction                12% Reduction               18% Reduction
            Brompton Standard Wheel Size         16.375 inches              16.375 inches               16.375 inches               16.375 inches             Note
  Data
                             Rear Sprocket           13     teeth                14     teeth                13     teeth                14     teeth         Help
  Entry                   Front Chain Ring           50     teeth                50     teeth                44     teeth                44     teeth         Help
  Area
                  Resulting Sprocket Ratio        3.846 to 1                  3.571 to 1                  3.385 to 1                  3.143 to 1              Note
          Resulting Direct Drive Wheel Size        63.0    inches              58.5    inches              55.4    inches              51.5    inches         Note
                                                                                                                                                          Resulting % of
         REAR HUB GEAR SELECTION               Resulting Wheel Size        Resulting Wheel Size        Resulting Wheel Size        Resulting Wheel Size    Direct drive
   With Mountain Drive Engaged … 1st gear          18.4    inches     ##       17.1    inches     ##       16.2    inches     ##       15.0    inches       29.20%
                                 2nd gear          25.2    inches     ##       23.4    inches     ##       22.2    inches     ##       20.6    inches       40.00%         Note
                                  3rd gear         34.3    inches     ##       31.8    inches     ##       30.2    inches     ##       28.0    inches       54.40%
Without Mountain Drive Engaged …. 1st gear         46.0    inches     ##       42.7    inches     ##       40.5    inches     ##       37.6    inches       73.00%
                                 2nd gear          63.0    inches     ##       58.5    inches     ##       55.4    inches     ##       51.5    inches      100.00%         Note
                                  3rd gear         85.7    inches     ##       79.5    inches     ##       75.4    inches     ##       70.0    inches      136.00%



      To CLEAR Screen of Messages:                              CLICK HERE to CLEAR SCREEN of MESSAGE WINDOWS




                                                                                                                                                            Page 9
                                           The BLUE entry points              Blue          below are where you may enter combinations
        USER INSTRUCTIONS:                 of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                           and the chart will compute the resulting Wheel Sizes for the different Gear Settings.                                     CLICK HERE
                                           You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                              to Return to
   Mouse or Keyboard TAB key:              which cycle you through the various data entry points or by MOUSE CLICKING the entry                                        Table of
                                           point allowing you to enter different spRocket teeth values for comparison combinations.
                                                                                                                                                                       Contents
                                           On the right side of the chart, you will see the words HELP and NOTE areas. MOUSE CLICK
     HELP Messages & Notes:                on these words for the Help or Note message associated with that area.

                    SRAM 6 Speed Rear Derailleur with Front Derailleur Option
                                                 Standard                       Standard                        Standard                         Standard
          Brompton Standard Wheel Size         16.375 inches                  16.375 inches                   16.375 inches                    16.375 inches             Note

Data                SMALL Chain Ring                39     teeth                    39     teeth                    39     teeth                    39     teeth         Help
Entry               LARGE Chain Ring                53     teeth                    53     teeth                    53     teeth                    53     teeth         Help
                  LARGE Rear Sprocket               15     teeth                    15     teeth                    15     teeth                    15     teeth         Help
Area              SMALL Rear Sprocket               13     teeth                    13     teeth                    13     teeth                    13     teeth         Help
            1st Resulting Sprocket Ratio        2.600    to 1                   2.600    to 1                   2.600    to 1                    2.600   to 1
           2nd Resulting Sprocket Ratio         3.000    to 1                   3.000    to 1                   3.000    to 1                    3.000   to 1
                                                                                                                                                                         Note
           3rd Resulting Sprocket Ratio         3.533    to 1                   3.533    to 1                   3.533    to 1                    3.533   to 1
            4th Resulting Sprocket Ratio        4.077    to 1                   4.077    to 1                   4.077    to 1                    4.077   to 1
   Resulting 1st Direct Drive Wheel Size          42.6    inches                 42.6     inches                 42.6     inches                  42.6    inches
   Resulting 2nd Direct Drive Wheel Size          49.1    inches                 49.1     inches                 49.1     inches                  49.1    inches
                                                                                                                                                                         Note
   Resulting 3rd Direct Drive Wheel Size          57.9    inches                 57.9     inches                 57.9     inches                  57.9    inches
   Resulting 4th Direct Drive Wheel Size          66.8    inches                 66.8     inches                 66.8     inches                  66.8    inches
                                                                                                                                                                     Resulting % of
       REAR HUB GEAR SELECTION               Resulting Wheel Size           Resulting Wheel Size            Resulting Wheel Size              Resulting Wheel Size
                                                                                                                                                                      Direct drive
                              1st gear            31.1    inches      ##         31.1     inches      ##         31.1     inches         ##       31.1    inches       73.00%
  Small Chain Ring and Large 2nd gear             42.6    inches      ##         42.6     inches      ##         42.6     inches         ##       42.6    inches      100.00%         Note
                             3rd gear             57.9    inches      ##         57.9     inches      ##         57.9     inches         ##       57.9    inches      136.00%
                              1st gear            35.9    inches      ##         35.9     inches      ##         35.9     inches         ##       35.9    inches       73.00%
  Small Chain Ring and Small
                             2nd gear             49.1    inches      ##         49.1     inches      ##         49.1     inches         ##       49.1    inches      100.00%         Note
                             3rd gear             66.8    inches      ##         66.8     inches      ##         66.8     inches         ##       66.8    inches      136.00%
                              1st gear            42.2    inches      ##         42.2     inches      ##         42.2     inches         ##       42.2    inches       73.00%
  Large Chain Ring and Large 2nd gear             57.9    inches      ##         57.9     inches      ##         57.9     inches         ##       57.9    inches      100.00%         Note
                             3rd gear             78.7    inches      ##         78.7     inches      ##         78.7     inches         ##       78.7    inches      136.00%
                              1st gear            48.7    inches      ##         48.7     inches      ##         48.7     inches         ##       48.7    inches       73.00%
  Large Chain Ring and Small 2nd gear             66.8    inches      ##         66.8     inches      ##         66.8     inches         ##       66.8    inches      100.00%         Note
                             3rd gear             90.8    inches      ##         90.8     inches      ##         90.8     inches         ##       90.8    inches      136.00%

   To CLEAR Screen of Messages:                                     CLICK HERE to CLEAR HELP MESSAGES and NOTES

                                                                                                                                                                       Page 11
                                                                                                                                       CLICK HERE
                                                                                                                    CLICK HERE
        Example & Explanation of SRAM 6 Speed Rear Derailleur with Front                                                               to Return to
                                                                                                                     to GO to
                            Derailleur Option Chart                                                                                      Table of
                                                                                                                    Actual Chart
                                                                                                                                         Contents


                   SRAM 6 Speed Rear Derailleur with Front Derailleur Option
                                               Standard                    Notes Sprocket ratios other than the Brompton Standard ratio
          Brompton Standard Wheel Size       16.375 inches                 The "Actual" physical wheel diameter size

Data                 SMALL Chain Ring             39     teeth             The number of teeth in the SMALL Chain Ring (You will be allowed to vary this)
Entry                LARGE Chain Ring             53     teeth             The number of teeth in the LARGE Chain Ring (You will be allowed to vary this)
                   LARGE Rear Sprocket            15     teeth             The number of teeth in the LARGE Rear sprocket (You will be allowed to vary this)
Area               SMALL Rear Sprocket            13     teeth             The number of teeth in the SMALL Rear sprocket (You will be allowed to vary this)
             1st Resulting Sprocket Ratio      2.600   to 1                Resulting ratio with the SMALL Chain Ring & LARGE Rear Sprocket engaged
            2nd Resulting Sprocket Ratio       3.000   to 1                Resulting ratio with the SMALL Chain Ring & SMALL Rear Sprocket engaged
            3rd Resulting Sprocket Ratio       3.533   to 1                Resulting ratio with the LARGE Chain Ring & LARGE Rear Sprocket engaged
            4th Resulting Sprocket Ratio       4.077   to 1                Resulting ratio with the LARGE Chain Ring & SMALL Rear Sprocket engaged
    Resulting 1st Direct Drive Wheel Size       42.6    inches             Resulting WHEEL SIZE in Direct Drive from 1st Sprocket ratio above
    Resulting 2nd Direct Drive Wheel Size       49.1    inches             Resulting WHEEL SIZE in Direct Drive from 2nd Sprocket ratio above
    Resulting 3rd Direct Drive Wheel Size       57.9    inches             Resulting WHEEL SIZE in Direct Drive from 3rd Sprocket ratio above
    Resulting 4th Direct Drive Wheel Size       66.8    inches             Resulting WHEEL SIZE in Direct Drive from 4th Sprocket ratio above
       REAR HUB GEAR SELECTION              Resulting Wheel Size
                              1st gear          31.1    inches     ##    Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
  Small Chain Ring and Large 2nd gear           42.6    inches     ##   SMALL Chain Ring & LARGE               With Rear Hub 2nd gear engaged (direct drive)
                             3rd gear           57.9    inches     ##                                          With Rear Hub 3rd gear engaged
                              1st gear          35.9    inches     ##    Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
  Small Chain Ring and Small
                             2nd gear           49.1    inches     ##   SMALL Chain Ring & SMALL               With Rear Hub 2nd gear engaged (direct drive)
                             3rd gear           66.8    inches     ##                                          With Rear Hub 3rd gear engaged
                              1st gear          42.2    inches     ##    Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
  Large Chain Ring and Large 2nd gear           57.9    inches     ##   LARGE Chain Ring & LARGE               With Rear Hub 2nd gear engaged (direct drive)
                             3rd gear           78.7    inches     ##                                          With Rear Hub 3rd gear engaged
                              1st gear          48.7    inches     ##    Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
  Large Chain Ring and Small 2nd gear           66.8    inches     ##   LARGE Chain Ring & SMALL               With Rear Hub 2nd gear engaged (direct drive)
                             3rd gear           90.8    inches     ##                                          With Rear Hub 3rd gear engaged




                                                                                                                                          Page 10
                                                                                                                                             CLICK HERE
               Example & Explanation of SRAM 6 Speed Derailleur with 3 Gear Hub                                           CLICK HERE
                                                                                                                                             to Return to
                                                                                                                           to GO to
                           with/without Mountain Drive Option Chart                                                       Actual Chart
                                                                                                                                               Table of
                                                                                                                                               Contents




           SRAM 6 Speed Rear Derailleur with 3 Gear Hub with/without Mountain Drive Option
                                                      Standard                   Notes Sprocket ratios other than the Brompton Standard ratio
                 Brompton Standard Wheel Size       16.375 inches                The "Actual" physical wheel diameter size
      Data                    Front Chain Ring           50     teeth            The number of teeth in the Front Chain Ring (You will be allowed to vary this)
      Entry               LARGE Rear Sprocket            15     teeth            The number of teeth in the LARGE Rear sprocket (You will be allowed to vary this)
      Area                SMALL Rear Sprocket            13     teeth            The number of teeth in the SMALL Rear sprocket (You will be allowed to vary this)

                    1st Resulting Sprocket Ratio      3.333 to 1                 Resulting ratio with the LARGE Rear Sprocket engaged
                   2nd Resulting Sprocket Ratio       3.846 to 1                 Resulting ratio with the SMALL Rear Sprocket engaged
           Resulting 1st Direct Drive Wheel Size       54.6    inches            Resulting WHEEL SIZE in Direct Drive from 1st Sprocket ratio above
           Resulting 2nd Direct Drive Wheel Size       63.0    inches            Resulting WHEEL SIZE in Direct Drive from 2nd Sprocket ratio above

               REAR HUB GEAR SELECTION             Resulting Wheel Size
                                    1st gear           15.9    inches     ##   Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
  With        With LARGE rear      2nd gear            21.8    inches     ##    LARGE Rear Sprocket &                With Rear Hub 2nd gear engaged (direct drive)
Mountain      sprocket engaged     3rd gear            29.7    inches     ##                                         With Rear Hub 3rd gear engaged
 Drive                              1st gear           18.4    inches     ##   Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
              With SMALL rear
Engaged                            2nd gear            25.2    inches     ##    SMALL Rear Sprocket &                With Rear Hub 2nd gear engaged (direct drive)
              sprocket engaged                                                                                       With Rear Hub 3rd gear engaged
                                   3rd gear            34.3    inches     ##
                                    1st gear           39.8    inches     ##   Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
Without       With LARGE rear      2nd gear            54.6    inches     ##                                         With Rear Hub 2nd gear engaged (direct drive)
                                                                                LARGE Rear Sprocket &
              sprocket engaged
Mountain                           3rd gear            74.2    inches     ##                                         With Rear Hub 3rd gear engaged
 Drive                              1st gear           46.0    inches     ##   Resulting Wheel Sizes with            With Rear Hub 1st gear engaged
              With SMALL rear
Engaged                            2nd gear            63.0    inches     ##    SMALL Rear Sprocket &                With Rear Hub 2nd gear engaged (direct drive)
              sprocket engaged                                                                                       With Rear Hub 3rd gear engaged
                                   3rd gear            85.7    inches     ##




                                                                                                                                                Page 12
                                                   The BLUE entry points             Blue          below are where you may enter combinations
               USER INSTRUCTIONS:
                                                   of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                                   and the chart will compute the resulting Wheel Sizes for the different Gear Settings.                                    CLICK HERE
           Mouse or Keyboard TAB key:              You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                             to Return to
                                                   which cycle you through the various data entry points or by MOUSE CLICKING the entry                                       Table of
                                                   point allowing you to enter different sprocket teeth values for comparison combinations.                                   Contents

              HELP Messages & Notes:               On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK
                                                   on these words for the Help or Note message associated with that area.



            SRAM 6 Speed Rear Derailleur with 3 Gear Hub with/without Mountain Drive Option
                                                         Standard                     12% Reduction                       Standard                    12% Reduction
                 Brompton Standard Wheel Size          16.375 inches                   16.375 inches                    16.375 inches                  16.375 inches            Note
      Data                   Front Chain Ring               50      teeth                    44     teeth                    50      teeth                 44     teeth         Help
      Entry               LARGE Rear Sprocket               15      teeth                    15     teeth                    15      teeth                 15     teeth         Help
      Area                SMALL Rear Sprocket               13      teeth                    13     teeth                    13      teeth                 13     teeth         Help
                    1st Resulting Sprocket Ratio        3.333 to 1                       2.933 to 1                      3.333 to 1                     2.933 to 1
                                                                                                                                                                                Note
                   2nd Resulting Sprocket Ratio         3.846 to 1                       3.385 to 1                      3.846 to 1                     3.385 to 1
           Resulting 1st Direct Drive Wheel Size          54.6     inches                   48.0   inches                  54.6     inches               48.0    inches
                                                                                                                                                                                Note
           Resulting 2nd Direct Drive Wheel Size          63.0     inches                   55.4   inches                  63.0     inches               55.4    inches
                                                                                                                                                                            Resulting % of
               REAR HUB GEAR SELECTION               Resulting Wheel Size            Resulting Wheel Size             Resulting Wheel Size           Resulting Wheel Size    Direct drive
                                    1st gear              15.9     inches      ##           14.0   inches      ##          15.9     inches      ##       14.0    inches       29.20%
  With        With LARGE rear      2nd gear               21.8     inches      ##           19.2   inches      ##          21.8     inches      ##       19.2    inches       40.00%         Note
Mountain      sprocket engaged     3rd gear               29.7     inches      ##           26.1   inches      ##          29.7     inches      ##       26.1    inches       54.40%
 Drive                              1st gear              18.4     inches      ##           16.2   inches      ##          18.4     inches      ##       16.2    inches       29.20%
              With SMALL rear
Engaged                            2nd gear               25.2     inches      ##           22.2   inches      ##          25.2     inches      ##       22.2    inches       40.00%         Note
              sprocket engaged
                                   3rd gear               34.3     inches      ##           30.2   inches      ##          34.3     inches      ##       30.2    inches       54.40%
                                    1st gear              39.8     inches      ##           35.1   inches      ##          39.8     inches      ##       40.5    inches       73.00%
Without       With LARGE rear      2nd gear               54.6     inches      ##           48.0   inches      ##          54.6     inches      ##       55.4    inches      100.00%         Note
              sprocket engaged
Mountain                           3rd gear               74.2     inches      ##           65.3   inches      ##          74.2     inches      ##       75.4    inches      136.00%
 Drive                              1st gear              46.0     inches      ##           40.5   inches      ##          46.0     inches      ##       40.5    inches       73.00%
              With SMALL rear
Engaged                            2nd gear               63.0     inches      ##           55.4   inches      ##          63.0     inches      ##       55.4    inches      100.00%         Note
              sprocket engaged
                                   3rd gear               85.7     inches      ##           75.4   inches      ##          85.7     inches      ##       75.4    inches      136.00%

           To CLEAR Screen of Messages:                                     CLICK HERE to CLEAR HELP MESSAGES and NOTES

                                                                                                                                                                              Page 13
                                                                                                                      CLICK               CLICK
            Example & Explanation of STURMEY 3 Speed Gear Hub with/without                                           HERE to             HERE to
                                                                                                                      GO to              Return to
                              Mountain Drive Option Chart                                                             Actual             Table of
                                                                                                                      Chart              Contents




            CALCULATIONS FOR THE BROMPTON 3 SPEED STURMEY HUB

                                                 Standard                 Notes Sprocket ratios other than the Brompton Standard ratio
                       Selected Wheel Size    16.375 inches               The "Actual" physical wheel diameter size
                   Selected Rear Sprocket         13   teeth              The number of teeth in the Rear sprocket (You will be allowed to vary this)
                   Selected Front Sprocket        50   teeth              The number of teeth in the Front Chain Ring (You will be allowed to vary this)

                  Resulting Sprocket Ratio      3.846 to 1                The resulting sprocket ratio

          Resulting Direct Drive Wheel Size      63.0    inches           The resulting WHEEL SIZE in Direct Drive


           REAR HUB GEAR SELECTION            Resulting Wheel Size
   With Mountain Drive Engaged … 1st gear        18.7    inches      ##     RESULTING WHEEL                    With Rear Hub 1st gear engaged
                                 2nd gear        25.2    inches      ##     SIZES with Mountain                With Rear Hub 2nd gear engaged (direct drive)
                                  3rd gear       33.3    inches      ##        Drive Engaged                   With Rear Hub 3rd gear engaged
Without Mountain Drive Engaged …. 1st gear       46.7    inches      ##      RESULTING WHEEL                     NOTE: If you do not own the Mountain
                                 2nd gear        63.0    inches      ##     SIZES Mountain Drive                   Drive Option, these are the ONLY
                                  3rd gear       83.3    inches      ##         Disengaged                               Resulting wheel sizes.




                                                                                                                                                        Page 14
              USER INSTRUCTIONS:              The BLUE entry points        Blue      below are where you may enter combinations
                                              of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                              and the chart will compute the resulting Wheel Sizes for the different Gear Settings.                         CLICK
                                                                                                                                                           HERE to
       Mouse or Keyboard TAB key:             You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                 Return to
                                              which cycle you through the various data entry points or by MOUSE CLICKING the entry                         Table of
                                              point allowing you to enter different sprocket teeth values for comparison combinations.                     Contents
           HELP Messages & Notes:             On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK
                                              on these words for the Help or Note message associated with that area.



              CALCULATIONS FOR THE BROMPTON 3 SPEED STURMEY HUB

                                                  Standard                   7% Reduction               12% Reduction               12% Reduction
                       Selected Wheel Size     16.375 inches                 16.375 inches              16.375 inches               16.375 inches              Note
                   Selected Rear Sprocket          13 teeth                      14 teeth                   13 teeth                    13 teeth               Help
                   Selected Front Sprocket         50 teeth                      50 teeth                   44 teeth                    44 teeth               Help

                  Resulting Sprocket Ratio       3.846 to 1                   3.571 to 1                  3.385 to 1                  3.385 to 1               Note

          Resulting Direct Drive Wheel Size       63.0    inches                58.5    inches              55.4    inches              55.4    inches         Note

                                                                                                                                                           Resulting % of
           REAR HUB GEAR SELECTION             Resulting Wheel Size         Resulting Wheel Size        Resulting Wheel Size        Resulting Wheel Size    Direct drive
   With Mountain Drive Engaged … 1st gear         18.7    inches       ##       17.4    inches     ##       17.4    inches     ##       16.4    inches       29.68%
                                 2nd gear         25.2    inches       ##       23.4    inches     ##       23.4    inches     ##       22.2    inches       40.00%
                                  3rd gear        33.3    inches       ##       30.9    inches     ##       30.9    inches     ##       29.3    inches       52.90%
Without Mountain Drive Engaged …. 1st gear        46.7    inches       ##       43.4    inches     ##       43.4    inches     ##       41.1    inches       74.19%
                                 2nd gear         63.0    inches       ##       58.5    inches     ##       58.5    inches     ##       55.4    inches      100.00%
                                  3rd gear        83.3    inches       ##       77.3    inches     ##       77.3    inches     ##       73.3    inches      132.26%

      To CLEAR Screen of Messages:                                    CLICK HERE to CLEAR HELP MESSAGES and NOTES


                                                                                                                                                                            Page 15
                                                                                                                        CLICK              CLICK
           Example & Explanation of STURMEY 5 Speed Gear Hub with/without                                              HERE to            HERE to
                                                                                                                        GO to             Return to
                             Mountain Drive Option Chart                                                                Actual            Table of
                                                                                                                        Chart             Contents




   BROMPTON STURMEY 5 Speed Calculations with & without MOUNTAIN DRIVE OPTION
                                                  Standard                 Notes Sprocket ratios other than the Brompton Standard ratio
             Brompton Standard Wheel Size       16.375 inches              The "Actual" physical wheel diameter size
   Data                       Rear Sprocket          13     teeth          The number of teeth in the Rear sprocket (You will be allowed to vary this)
   Entry                   Front Chain Ring          50     teeth          The number of teeth in the Front Chain Ring (You will be allowed to vary this)
   Area
                   Resulting Sprocket Ratio       3.846 to 1               The resulting sprocket ratio
           Resulting Direct Drive Wheel Size       63.0    inches          The resulting WHEEL SIZE in Direct Drive
         REAR HUB GEAR SELECTION               Resulting Wheel Size
   With Mountain Drive Engaged … 1st gear          16.7    inches     ##                                        With Rear Hub 1st gear engaged
                                 2nd gear          19.9    inches     ##    RESULTING WHEEL                     With Rear Hub 2nd gear engaged
                                  3rd gear         25.2    inches     ##    SIZES with Mountain                 With Rear Hub 3rd gear engaged (direct drive)
                                  4th gear         31.7    inches     ##       Drive Engaged                    With Rear Hub 4th gear engaged
                                  5th gear         37.6    inches     ##                                        With Rear Hub 5th gear engaged
Without Mountain Drive Engaged …. 1st gear         41.6    inches     ##
                                 2nd gear          49.8    inches     ##    RESULTING WHEEL                       NOTE: If you do not own the Mountain
                                  3rd gear         63.0    inches     ##   SIZES Mountain Drive                     Drive Option, these are the ONLY
                                  4th gear         79.2    inches     ##       Disengaged                                 Resulting wheel sizes.
                                  5th gear         94.1    inches     ##




                                                                                                                                                         Page 16
          USER INSTRUCTIONS:                  The BLUE entry points             Blue          below are where you may enter combinations
                                              of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                              and the chart will compute the resulting Wheel Sizes for the different Gear Settings.                                    CLICK
                                                                                                                                                                      HERE to
     Mouse or Keyboard TAB key:               You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard
                                                                                                                                                                      Return to
                                              which cycle you through the various data entry points or by MOUSE CLICKING the entry
                                                                                                                                                                      Table of
                                              point allowing you to enter different sprocket teeth values for comparison combinations.
                                                                                                                                                                      Contents
        HELP Messages & Notes:                On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK
                                              on these words for the Help or Note message associated with that area.



     BROMPTON STURMEY 5 Speed Calculations with & without MOUNTAIN DRIVE OPTION
                                                    Standard                       7% Reduction                    12% Reduction               18% Reduction
            Brompton Standard Wheel Size          16.375 inches                    16.375 inches                   16.375 inches               16.375 inches             Note
  Data                       Rear Sprocket             13      teeth                    14     teeth                     13     teeth               14     teeth         Help
  Entry                   Front Chain Ring             50      teeth                    50     teeth                     44     teeth               44     teeth         Help
  Area
                  Resulting Sprocket Ratio         3.846 to 1                       3.571 to 1                       3.385 to 1                  3.143 to 1              Note
          Resulting Direct Drive Wheel Size          63.0     inches                   58.5   inches                   55.4    inches             51.5    inches         Note
                                                                                                                                                                     Resulting % of
         REAR HUB GEAR SELECTION                Resulting Wheel Size            Resulting Wheel Size             Resulting Wheel Size         Resulting Wheel Size    Direct drive
   With Mountain Drive Engaged … 1st gear            16.7     inches      ##           15.5   inches       ##          14.7    inches    ##       13.6    inches       26.45%
                                 2nd gear            19.9     inches      ##           18.5   inches       ##          17.5    inches    ##       16.3    inches       31.61%
                                  3rd gear           25.2     inches      ##           23.4   inches       ##          22.2    inches    ##       20.6    inches       40.00%         Note
                                  4th gear           31.7     inches      ##           29.4   inches       ##          27.9    inches    ##       25.9    inches       50.32%
                                  5th gear           37.6     inches      ##           34.9   inches       ##          33.1    inches    ##       30.8    inches       59.76%
Without Mountain Drive Engaged …. 1st gear           41.6     inches      ##           38.7   inches       ##          36.7    inches    ##       34.0    inches       66.13%
                                 2nd gear            49.8     inches      ##           46.2   inches       ##          43.8    inches    ##       40.7    inches       79.03%
                                  3rd gear           63.0     inches      ##           58.5   inches       ##          55.4    inches    ##       51.5    inches      100.00%         Note
                                  4th gear           79.2     inches      ##           73.6   inches       ##          69.7    inches    ##       64.7    inches      125.81%
                                  5th gear           94.1     inches      ##           87.4   inches       ##          82.8    inches    ##       76.9    inches      149.39%


      To CLEAR Screen of Messages:                               CLICK HERE to CLEAR HELP MESSAGES and NOTES


                                                                                                                                                                     Page 17
                  EXAMPLE & EXPLANATION OF CHART WITH FRONT DERAILLEUR OPTION

                                                             Go back to TABLE OF CONTENTS                    CLICK HERE

                                                           Go to ACTUAL DATA ENTRY CHART                     CLICK HERE



            BROMPTON STURMEY 5 SPEED GEAR CALCULATIONS with the FRONT DERAILLEUR OPTION
                                                   Standard                   Notes Sprocket ratios other than the Brompton Standard ratio
              Brompton Standard Wheel Size       16.375 inches                The "Actual" physical wheel diameter size
   Data                      REAR Sprocket            13     teeth            The number of teeth in the Rear sprocket (You will be allowed to vary this)
   Entry                  SMALL Chain Ring            39     teeth            The number of teeth in the Small Front Chain Ring (You will be allowed to v
   Area                   LARGE Chain Ring            53     teeth            The number of teeth in the Large Front Chain Ring (You will be allowed to v

        Small Chain Resulting Sprocket Ratio       3.000 to 1                 The resulting sprocket ratio with the SMALL chain ring engaged
        Large Chain Resulting Sprocket Ratio       4.077 to 1                 The resulting sprocket ratio with the LARGE chain ring engaged
Resulting Small Chain Direct Drive Wheel Size       49.1    inches            The resulting WHEEL SIZE in Direct Drive with the SMALL chain ring engag
Resulting Large Chain Direct Drive Wheel Size       66.8    inches            The resulting WHEEL SIZE in Direct Drive with the LARGE chain ring engag

         REAR HUB GEAR SELECTION                Resulting Wheel Size
With SMALL Chain Ring Engaged … 1st gear            32.5    inches     ##                                          With Rear Hub 1st gear engaged
                               2nd gear             38.8    inches     ##       RESULTING WHEEL                    With Rear Hub 2nd gear engaged
                                3rd gear            49.1    inches     ##     SIZES with SMALL Chain               With Rear Hub 3rd gear engaged (dire
                                4th gear            61.8    inches     ##          Ring Engaged                    With Rear Hub 4th gear engaged
                                5th gear            73.4    inches     ##                                          With Rear Hub 5th gear engaged
With LARGE Chain Ring Engaged … 1st gear            44.1    inches     ##                                          With Rear Hub 1st gear engaged
                               2nd gear             52.8    inches     ##       RESULTING WHEEL                    With Rear Hub 2nd gear engaged
                                3rd gear            66.8    inches     ##     SIZES with LARGE Chain               With Rear Hub 3rd gear engaged (dire
                                4th gear            84.0    inches     ##          Ring Engaged                    With Rear Hub 4th gear engaged
                                5th gear            99.7    inches     ##                                          With Rear Hub 5th gear engaged
To CLEAR Screen of Messages:   CLICK HERE to CLEAR HELP MESSAGES and NOTES
PTION




DERAILLEUR OPTION
 ompton Standard ratio


 et (You will be allowed to vary this)
 Chain Ring (You will be allowed to vary this)
 Chain Ring (You will be allowed to vary this)

MALL chain ring engaged
 RGE chain ring engaged
 ive with the SMALL chain ring engaged
 ive with the LARGE chain ring engaged


 ith Rear Hub 1st gear engaged
 ith Rear Hub 2nd gear engaged
 ith Rear Hub 3rd gear engaged (direct drive)
 ith Rear Hub 4th gear engaged
 ith Rear Hub 5th gear engaged
 ith Rear Hub 1st gear engaged
 ith Rear Hub 2nd gear engaged
 ith Rear Hub 3rd gear engaged (direct drive)
 ith Rear Hub 4th gear engaged
 ith Rear Hub 5th gear engaged
and NOTES
            Page 18
                                                The BLUE entry points             Blue          below are where you may enter combinations
           USER INSTRUCTIONS:
                                                of different values for the number of teeth on the CHAIN RING and REAR sprockets
                                                and the chart will compute the resulting Wheel Sizes for the different Gear Settings.                                  CLICK HERE
       Mouse or Keyboard TAB key:               You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard                                           to Return to
                                                which cycle you through the various data entry points or by MOUSE CLICKING the entry                                     Table of
                                                point allowing you to enter different sprocket teeth values for comparison combinations.                                 Contents

         HELP Messages & Notes:                 On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK
                                                on these words for the Help or Note message associated with that area.



   BROMPTON STURMEY 5 SPEED GEAR CALCULATIONS with FRONT DERAILLEUR OPTION
                                                      Standard                      7% Reduction                    13% Reduction                  Standard
              Brompton Standard Wheel Size          16.375 inches                   16.375 inches                   16.375 inches                16.375 inches             Note
   Data                      REAR Sprocket               13      teeth                    14     teeth                    15     teeth                13     teeth         Help
   Entry                  SMALL Chain Ring               39      teeth                    39     teeth                    39     teeth                39     teeth         Help
   Area                   LARGE Chain Ring               53      teeth                    53     teeth                    53     teeth                53     teeth         Help
        Small Chain Resulting Sprocket Ratio         3.000 to 1                      2.786 to 1                       2.600 to 1                   3.000 to 1
                                                                                                                                                                           Note
        Large Chain Resulting Sprocket Ratio         4.077 to 1                      3.786 to 1                       3.533 to 1                   4.077 to 1
Resulting Small Chain Direct Drive Wheel Size          49.1     inches                   45.6   inches                  42.6    inches              49.1    inches
                                                                                                                                                                           Note
Resulting Large Chain Direct Drive Wheel Size          66.8     inches                   62.0   inches                  57.9    inches              66.8    inches
                                                                                                                                                                       Resulting % of
         REAR HUB GEAR SELECTION                  Resulting Wheel Size            Resulting Wheel Size            Resulting Wheel Size          Resulting Wheel Size    Direct drive
With SMALL Chain Ring Engaged … 1st gear               32.5     inches      ##           30.2   inches      ##          28.2    inches     ##       32.5    inches       66.13%
                               2nd gear                38.8     inches      ##           36.1   inches      ##          33.6    inches     ##       38.8    inches       79.03%
                                3rd gear               49.1     inches      ##           45.6   inches      ##          42.6    inches     ##       49.1    inches      100.00%         Note
                                4th gear               61.8     inches      ##           57.4   inches      ##          53.6    inches     ##       61.8    inches      125.81%
                                5th gear               73.4     inches      ##           68.1   inches      ##          63.6    inches     ##       73.4    inches      149.39%
With LARGE Chain Ring Engaged … 1st gear               44.1     inches      ##           41.0   inches      ##          38.3    inches     ##       44.1    inches       66.13%
                               2nd gear                52.8     inches      ##           49.0   inches      ##          45.7    inches     ##       52.8    inches       79.03%
                                3rd gear               66.8     inches      ##           62.0   inches      ##          57.9    inches     ##       66.8    inches      100.00%         Note
                                4th gear               84.0     inches      ##           78.0   inches      ##          72.8    inches     ##       84.0    inches      125.81%
                                5th gear               99.7     inches      ##           92.6   inches      ##          86.4    inches     ##       99.7    inches      149.39%



       To CLEAR Screen of Messages:                                      CLICK HERE to CLEAR HELP MESSAGES and NOTES                                                        Page 19
            GEARING STANDARDS FOR USA BROMPTON FOLDING BIKES
Wheel Diameter Size                                         Brompton Standard Gearing                        SPROCKET RATIOS
                        USA         16.375      inches           No Gear Reduction
                                                                               Chain Ring       50   teeth     Standard Ratio
Sturmey Archer Rear Hub                                                      Rear sprocket      13   teeth      3.846 to 1
    3 Speed Hub                 Pecentage of direct drive
                     1st gear     74.19%       percent      Reduced Gearing Options                           Compared to Std
                    2nd gear     100.00%       percent           7% Gear Reduction
                    3rd gear     132.26%       percent                          Chain Ring      50   teeth   7% Reduced Ratio
    5 Speed Hub                                                              Rear sprocket      14   teeth     3.571 to 1
                     1st gear     66.13%       percent           12% Gear Reduction
                    2nd gear      79.03%       percent                          Chain Ring      44   teeth   12% Reduced Ratio
                    3rd gear     100.00%       percent                       Rear sprocket      13   teeth      3.385 to 1
                    4th gear     125.81%       percent           18% Gear Reduction
                    5th gear     146.39%       percent                          Chain Ring      44   teeth   18% Reduced Ratio
                                                                             Rear sprocket      14   teeth      3.143 to 1
Sram Spectro Rear Hub                                            23% Gear Reduction
   3 Speed Hub                  Pecentage of direct drive                       Chain Ring      44   teeth   23% Reduced Ratio
                    1st gear      73.00%       percent                       Rear sprocket      15   teeth      2.933 to 1
                   2nd gear      100.00%       percent
                    3rd gear     136.00%       percent      Single Chain Ring Options
   Dual Rear Derailleur with 3 Speed Hub                                          Standard      50   teeth
  Small rear sprocket / 1st gear 73.00%        percent                      Reduced gearing     44   teeth
        (engaged)      2nd gear 100.00%        percent
                        3rd gear 136.00%       percent      Single Rear Sprocket Options                               CLICK HERE to
  Large rear sprocket / 1st gear 73.00%        percent                              Standard    13   teeth             Return to The
        (engaged)      2nd gear 100.00%        percent                       Reduced Gearing    14   teeth
                        3rd gear 136.00%       percent               Further Reduced Gearing    15   teeth
                                                                                                                          Table of
                                                                                                                         Contents
Mountain Drive Gearing          Pecentage of direct drive   Front Dual Derailleur Offering
                 Direct Drive    100.00%       percent                         Large sprocket   53   teeth
                   Low Drive     250.00%       percent                         Small sprocket   39   teeth

                                                            Rear Dual Derailleur Offering
 Herein are the Standard Offerings from Brompton.
                                                                               Large sprocket   15   teeth
       Other combinations can be requested.
                                                                               Small sprocket   13   teeth
                                                                                                                                 Page 20

				
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