Docstoc

app_mountainbike

Document Sample
app_mountainbike Powered By Docstoc
					Santa Cruzʼs latest suspension: APP | Millimeters



   NEW!        mobile.bicycling.com                             Find us on Facebook                                Follow @BicyclingMag on Twitter




  Millimeters

                        « Santa Cruz’s New Carbon Nomad | Main |
                                                                                                ABOUT                                     RECENT POSTS

                                                                                                                                          Santa Cruz’s latest suspension: APP
      April 13th, 2010                                                                          Test Director        Matt Phillips will
                                                                                                                                          Santa Cruz’s New Carbon Nomad
                                                                                                download his brain (for better or
                                                                                                                                          2011 SRAM X.7: 2×10 gets cheaper
                                                                                                worse) to give you the latest gear
    Santa Cruz’s latest suspension: APP                                                         news, tech info, rumors and details...
                                                                                                                                          2010 Trek Remedy OCLV and Scratch
                                                                                                                                          SSWC 2009: Mea Maxima Culpa
                                                                                                lots of details. He's the kind of guy
                                                                                                who will write a surprisingly accurate,
                                                                                                                                          MONTHLY ARCHIVES
                                                                                                several thousand-word history of XTR
                                                                                                from memory, just because he has          April 2010
                                                                                                nothing    better     to  do    on an     March 2010
                                                                                                international fight.                      November 2009
                                                                                                                                          September 2009
                                                                                                OTHER BLOGS                               July 2009
                                                                                                                                          May 2009
                                                                                                Colorado Premier Training                 March 2009
                                                                                                Durango Cyclery                           February 2009
                                                                                                Durango DEVO                              November 2008
                                                                                                Durango Wheel Club                        September 2008
                                                                                                Fort Lewis Cycling
                                                                                                Iron Horse Bicycle Classic                RSS
                                                                                                Mountain Bike Specialists
                                                                                                Ska Brewing                                                ;
                                                                                                Analytic Cycling
                                                                                                Bicycle Design
                                                                                                Bicycle Marketing Watch
    2010 might be the year you get sick of reading about new bikes from Santa Cruz.             Bicycle Retailer
    Though they’re probably big enough that we shouldn’t call them small, they’re               Bike Europe
    certainly not big: when I visited recently, the big debate was what the new bring-your-     Bike For All
    dog-to-work policy was going to be. Not-smallness and not-bigness (and dog                  Bike Hugger
                                                                                                BikeBiz
    policies) have not prevented Santa Cruz from churning out some very desirable bikes.
                                                                                                BikeTechReview
    I detailed the new Nomad Carbon recently. But, as Santa Cruz pushes further upward          Drunkcyclist.com
    with VPP carbon bikes, they’ve also made changes to their single pivot bikes to make        Masiguy
    those bikes more affordable. This created a somewhat expansive gulf in the line,            Science of Cycling
    which, though the miracle of engineering, is now filled with bikes that are a little bit    Single Speed Outlaw
                                                                                                Urban Velo
    VPP and a little bit single pivot.
                                                                                                Wheel Fanatyk

    The 125mm Nickel and 150mm Butcher use Santa
                                                                                                ALL MOUNTAIN BIKE
    Cruz’s latest suspension system: APP. “APP” stands                                          BLOGS
    for Actual Pivot Point, but the name doesn’t really
                                                                                                Junkshow
    mean anything, which Santa Cruz admits. They
                                                                                                MB Word
    needed to call the new design something and ‘APP’                                           Millimeters
    was better than ‘the bike with the new suspension.’                                         New Flavors
                                                                                                Toolbox
    In the simplest terms, APP is the result of blending
    Santa Cruz’s proven single pivot suspension platform
    with the shock rate of their VPP bikes. The design is
                                                              Single pivot plus smiling shock




http://bicycling.com/blogs/millimeters/2010/04/13/santa-cruzs-latest-suspension-app/[4/14/10 9:29:56 AM]
Santa Cruzʼs latest suspension: APP | Millimeters

    based on the patent recently issued to Santa Cruz,
                                                                         rate equals APP
    (7,581,743, Bicycle rear wheel suspension system
    with controlled variable shock rate). Though the images contained in the patent show
    a bike with a floating shock, APP in production form uses a, er, not-floating shock.
    We’ll get into how APP came to have a non-floating shock in a bit.

    But first…

    Let’s start by defining shock rate. According to Santa
    Cruz’s engineering director, Joe Graney (his name is
    on the “APP” patent), shock rate is, “Shock
    compression divided by vertical wheel travel - this is
    the inverse of leverage rate.” With APP/VPP, “The
    shock rate amount decreases, then increases. So,
    the leverage is increasing initially, reaches a
    maximum mid-stroke, then decreasing at the end so
    you don’t bottom out.” A plot of the APP shock rate
    creates a subtle smiley face.                               The Butcher's shock rate (in blue),
                                                                mirrors the Nomad's (in red). The
    Any why is the VPP/APP shock rate desirable? “With
                                                                Heckler's rate is shown in yellow.
    the VPP/APP shock rate, the bike feels like it has
    more travel. Same bump, same trail, you use more of the shock stroke so it feels like
    your bike absorbs more. It’s noticeable, and when we were doing the development,
    we [rode] out the [Heckler and Butcher mule back-to-back]. Everyone who rode the
    two said the same thing; not that the Heckler was a bad bike, but that the Butcher
    mule felt like it had more travel and absorbed bumps better,” said Graney in an
    email.

    Now, savvy readers may ask themselves, “If using more shock stroke for a given hit is
    desirable, why not just simply increase leverage ratio?” Graney responds, “You can
    increase leverage ratio solely, which would be “falling shock rate”. If you only offer a
    falling rate, then the bike has a tendency to bottom out the suspension on bigger
    hits/jumps/drops etc. If you solely have a decreasing leverage ratio (rising shock rate,
    which many systems have), then the bike feels shorter travel than it truly is, but
    without any of the benefits one can take advantage of with shorter travel. If it has too
    much rising rate, then you never get to use all the travel, it just ramps up too much.”

    Asked to expand on, “…the benefits one can take
    advantage of with shorter travel,” Graney wrote, “The
    benefits of shorter travel could be geometry driven (a
    lower BB), a bike that pedals better (because you
    don’t have all the squishing around), shorter
    chainstays (easier to not hit the wheel on seat tube),
    and maybe a shorter/lighter shock. Basically, who
    wants an six-inch bike that feels like 4.5″ when you
    hit stuff? We’re trying to make a five-inch bike that
    feels like six when you go downhill, but five when you       The 125mm Nickel fills a hole in
    go up.”                                                            the Santa Cruz line

    So the VPP/APP shock rate aims to stake out the precious middle ground. Cue cut
    and paste from the press release, “…during the initial falling rate part of travel, the
    suspension is very responsive to bump forces - it uses more of the suspension for a
    given bump size. Basically, this feels like “more travel” than is really there. As APP
    suspension progresses through mid-stroke, the shock rate flattens and then changes
    sign to a rising rate. This translates to a gradual shift from the plush initial travel into
    more heavy impact resistance deeper in the stroke. As the suspension nears bottom-
    out, the shock rate progression helps resist bottoming, and creates superb jump
    landing and g-out characteristics.”

    Creating the VPP shock rate with a single pivot isn’t
    easy because the engineers didn’t have the tuning
    control that a pair of counter-rotating links affords. At
    first Santa Cruz thought they would need to use a
    floating shock, as the drawings in the patent reflect.



http://bicycling.com/blogs/millimeters/2010/04/13/santa-cruzs-latest-suspension-app/[4/14/10 9:29:56 AM]
Santa Cruzʼs latest suspension: APP | Millimeters




    However, when it came time to build the first test
    mules for what would become the APP system, Nick
    Anderson, Santa Cruz’s Canadian Whiz Kid
    (engineer), figured out a way to get the desired
    shock rate with two small links and a non-floating         Mule Joe Mama helped prove the
    shock. This ingenuity made building the test mules              simpler APP execution
    much simpler but created a conundrum: they now
    had two ways to build the system. One was so small and simple you might not even
    notice at first glance. The other (as reflected in the patent), was more complicated,
    but the stuff that made it more than the average single pivot bike was much easier to
    see. Santa Cruz mulled the pros and cons and decided that simple was the way to
    go: in THIS case, the floating shock had no advantages other than a more unique
    look. That’s not to say Santa Cruz will never make a bike with a floating shock.
    Graney says that in this case simpler was better; in a different situation, the floater
    may be the winning choice. Reflecting, perhaps, the lessons learned in achieving the
    desired shock rate with a simpler system, laser etched on the APP’s link is a
    tantalizing clue, “U.S. Patent 7581743. Additional patents pending.”

    As a guy who’s been working at a bicycle magazine
    for over 13 years, and riding mountain bikes for over
    20, I was very surprised that, despite the hundreds of
    different executions of single pivot bikes, including
    single pivot with modifying linkage (”faux bar,” etc.)
    no one had stumbled across the smiley-face shock
    rate. “Yeah, it sure seems weird that its been done
    so many times and nobody’s done this, even by
    accident. To the best of my knowledge, and I’ve
    checked out a ton of them, nobody has. It seems like        The curve in the Nickel's down
    everyone has gone after the rising rate, or varying            tube near the BB creates
    how the rising rate rises,” Graney said.                   clearance for a water bottle in the
                                                               front triangle. The Butcher does
    The details
                                                                      not have this curve
    * Two bikes with the APP suspension system so far:
    the Butcher (150mm) and the Nickel (125mm).

    * APP is only available for 26 inch wheels right now. The Tallboy Carbon is still Santa
    Cruz’s only 29er, but that’s gotta change, right?

    * The Nickel fills a hole in Santa Cruz’s line between the Blur LT (140mm) and the
    Superlight/Blur XC (100ish mm). The geometry is unique as well: the top tube length,
    per size, is equal to a Blur XC (23″ on a medium), but the head angle is slacker than
    a, longer travel, Blur LT (Nickel, 68 degrees; BLT, 69 degrees).

    * The Butcher fits a lot like a Hecker (top tube length,
    seat tube length, head tube lenght, seat angle
    identical) but has a slacker head angle - 67.5 VS. 69.

    * Frame-only price, with Fox Float R shock and
    powdercoat finish is $1350 for both frames. Butcher
    and Nickel will be offered with fork, shock and parts
    kit options. Complete bike rices and details have not
    been released, but look at the Heckler and Blur LT
    bike builders on the Santa Cruz site for a general
                                                                Housing stops for Shimano and
    idea of what the options should be.
                                                                    SRAM front derailleurs.

    * Nickel and Butcher will not be offered in anodized
    colors. Side note: If you want any Santa Cruz bike in an anodized color, get it now.
    The company is doing away with anodized frames across the board.




http://bicycling.com/blogs/millimeters/2010/04/13/santa-cruzs-latest-suspension-app/[4/14/10 9:29:56 AM]
Santa Cruzʼs latest suspension: APP | Millimeters

    * The pivot location is the same as Santa Cruz’s single pivot bikes, so you can expect
    the pedaling and braking characteristics to be about the same as well. Shock rate
    does change the way the bike feels when pedaling and braking - though to a lesser
    degree than it changes bump performance - so, for instance, a Butcher’s pedaling
    feel will not be identical to a Heckler, even though travel and pivot location are the
    same.

    * The big difference between VPP and APP is pedaling manners. VPP’s instant
    center migration creates much more complex anti-squat characteristics and a more
    efficient pedaling feel.

    * The frames are aluminum. Both feature tapered
    head tubes (a feature that the current aluminum Blur
    LT does not have, but will eventually), guides for
    dropper seatposts and use the same locking pivot
    axle system as the Blur LT, Nomad, etc. The Butcher
    has ISCG05 tabs; it does not have Hammerschmidt
    housing guides.

    * The Nickel has two water bottle attachment points:
    one inside the front triangle, one under the down
                                                                The 15mm locking pivot axles are
    tube. The Butcher is a hydration-pack-only bike.
                                                                 found on all Santa Cruz bikes

    * You’ll notice two front derailleur housing stops on now. Butcher gets ISCG05 tabs.

    the bikes. The one on the non-drive side of the seat
    tube is for Shimano front derailleurs; the one on the drive side is for SRAM front
    derailleurs. This was necessary because SRAM’s recently introduced FDs have vastly
    different housing stop/cable pull specs than Shimano’s established specs. Get used
    to it: going forward, if frames are going to be compatible with both company’s
    drivetrains, there will need to be a similar accommodation (in most cases).

    * I had an opportunity to ride a prototype Butcher,
    however, I won’t share much because I was riding a
    too-big frame and my bike’s rear triangle was much
    different than the production rear triangle. I will share
    this very short impression: pedals like a Heckler,
    rides like a Blur LT. Naturally, there will be an in-
    depth review of a production APP bike in Mountain
    Bike Magazine soon.

    * If you’re going to Sea Otter, you can gaze upon
                                                                1.5/1.125 inch tapered head tube
    APP in person. If you want to ride one, APP bikes
                                                                 with zero stack upper cup and
    should be on the Santa Cruz demo fleet the
                                                                      traditional lower cup.
    beginning of may. Click “Demo” on the Santa Cruz
    site to see when Ariel and Abby will be near you.

     Post a comment

    You must be logged in to post a comment.




http://bicycling.com/blogs/millimeters/2010/04/13/santa-cruzs-latest-suspension-app/[4/14/10 9:29:56 AM]

				
DOCUMENT INFO