Story by Arthur Coldwells Photography by Don Williams

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Story by Arthur Coldwells Photography by Don Williams Powered By Docstoc
					     Story by Arthur Coldwells
              Photography by Don Williams

60   U LT I M A T E M O T O R C Y C L I N G   •   AUGUST 2010
High-performance tire comparison

                    AUGUST 2010   •   U LT I M A T E M O T O R C Y C L I N G   61
T        he joy of riding a fast motorcycle on an
         inviting canyon road or the occasional
         track day is well known. However, it
doesn’t take much of that type of mileage before
your tires become decidedly worn and you face
                                                                   A brace of Honda’s excellent CBR600RRs
                                                                were the test platform, and the precision ser-
                                                                vices of Danny DiNardo at Peak Performance
                                                                in Simi Valley were enlisted to weigh, measure,
                                                                and mount the tires to the Honda wheels; his
                                                                                                                     Once fitted to the bike, DiNardo measured
                                                                                                                  the circumference of each tire and the axle
                                                                                                                  heights to discover if there were any changes
                                                                                                                  to the Honda’s chassis geometry. Most made
                                                                                                                  negligible change, however the Michelins
the question of replacement.                                    findings fueled some interesting speculation.      dropped the front by 2.4mm and the Pirel-
   The original-equipment tires ordered by                         The stock Dunlop Qualifiers (at a com-          lis raised the rear by 5.3mm. Both of these
the manufacturers are mere shadows of their                     bined weight of 21.1 pounds) and the              alterations to axle position would reduce the
aftermarket siblings, hobbled by less rubber                    Michelin Power Pures (21.3 pounds) were           rake angle a little, implying that the steering
and lighter construction. Manufacturers often                   easily the lightest. The Dunlop Sportmax Q2s      of the 600RR would be speeded up consid-
supply several different tire brands on the same                were heaviest—some 2.8 pounds extra for the       erably, particularly with the Pirellis.
model, and which one ends up on the bike                        pair—and for sportbike enthusiasts obsessed          Clearly, to eliminate as many variables as
you buy is a random choice. Nevertheless, you                   with saving unsprung weight (especially if that   possible a controlled track test is mandatory.
are quickly going to need some replacement                      weight is distributed around the outside of the   Southern California’s Willow Springs Raceway
rubber and we were determined to find out                        wheel) we presumed that the Q2s, by compar-       was chosen for its high speeds and demanding
which tires will best satisfy riders oriented                   ison, would make the usually sweet-handling       technical corners—certainly a tire-shredder if
toward maximum performance.                                     Honda 600RR turn like a truck.                    ever there was one.

62   U LT I M A T E M O T O R C Y C L I N G   •   AUGUST 2010
                BRIDGESTONE                            DUNLOP                             PIRELLI                            MICHELIN

                                                                       Representing faster riders in          The Hondas started out the day on new
                                                                    the test was Tristan Schoenewald,      stock tires to give the riders a comparison
                                                                    a respected ex-AMA 600 Super-          baseline. After several sessions and a best lap
  The ambient temperature on the appointed                          sport racer with a National and        time of 1:41.0, the OE tires were clearly not
day was a balmy 72 degrees, and the test con-       several Regional WERA Championships to his             particularly fast and the riders reported some
cluded before the notorious afternoon Ante-         credit. He is fast, precise, and smooth. Schoe-        vagueness over bumps as well. Schoenewald
lope Valley winds had a chance to interfere.        newald can evaluate tires at the limits of their       generally liked the tire, but felt the grip was a
We drafted the prodigious mechanical skills of      traction while putting in consistent laps, always      bit lacking and had a couple of mild mid-turn
Rick Wall and Danny Coe to facilitate wheel         hitting his lines and braking points.                  slides to prove it.
fitment in the pits and ensure that all tire pres-      Associate Editor Jess McKinley is a highly             After the initial sessions on the stock tires,
sures were consistent with the manufacturer’s       accomplished off-road racer, but a racetrack           the test was conducted blind, with the riders
recommendations. Because of the high speeds         novice. His years of experience pushing two-           unaware of which brand of tire they were rid-
involved, we stiffened the 600RRs’ stock sus-       wheelers to their limits enable him to feel the        ing on, and at no stage did Schoenewald and
pension slightly at both ends of the bike, and      differences in the tires, but his lack of racetrack    McKinley discuss their test results with each
to ensure the stock steering geometry was           experience gives us a regular-guy impression           other. Comparisons of each set of tires were
maintained, each adjuster was cranked up one-       of the tires by lapping Willow Springs at speeds       made against their impressions of the stock
half turn.                                          more familiar to mere mortals.                         Dunlop Qualifiers.

                                                                                                          AUGUST 2010    •   U LT I M A T E M O T O R C Y C L I N G   63

                                                                                                Bridgestone Battlax BT-016
                                                                                                   As the sole tire supplier to MotoGP since last year,
                                                                                                Bridgestone has certainly carved out an enviable reputa-
                                                                                                tion. Who can forget 2008 when Valentino Rossi—hav-
                                                                                                ing floundered the year before— successfully changed to
                                                                                                Bridgestone tires, prompting Dani Pedrosa to insist mid-
                                                                                                season on switching to Bridgestone as well?
                                                                                                   The BT-016 is a dual-compound front, and triple-
                                                                                                compound rear tire that gets grippier as the lean angle
                                                                                                increases. Bridgestone also prefers a steel (over other
                                                                                                brands’ aramid fibers) mono-spiral belt construction to
                                                                                                give the carcass added strength. A significant two pounds
                                                                                                heavier than the stock tires, the Bridgestones took 0.8mm
                                                                                                height away from the front and 0.5mm from the rear,
                                                                                                which lowered the bike slightly but made minimal
                                                                                                changes to the geometry.
                                                                                                   McKinley was very impressed, as he felt the Bridge-
                                                                                                stones were softer and more compliant than the stock
                                                                                                tires, but a little slower to turn-in. “A big improvement
                                                                                                over the stock tires,” he enthused.
                                                                                                   Schoenewald’s best lap of 1:38.3 on the Bridgestones
                                                                                                was almost three seconds a lap quicker than the stock
                                                                                                rubber. He felt the BT-016s were a little harsh over
                                                                                                bumps, and he also noticed some front-end chatter at
                                                                                                full lean angle. Schoenewald complimented the tires on
                                                                                                their reliable turn-in and mid-corner traction, and said
                                                                                                he “felt comfortable and confident” on the BT-016s.
                                                                                                However, he also noted that “when I pushed hard, the
                                                                                                rear would lose grip quite suddenly,” and it was that lack
                                                                                                of predictability that ultimately cost him the ability to
                                                                                                go any faster.

                                                                                                Dunlop Sportmax Q2
                                                                                                   In 2010, Dunlop became the specified tire for the

                                                                                                AMA Championship, and the Q2 tire uses its propri-
                                                                                                etary N-Tec race technology.The rear tire is a dual com-
                                                                                                pound construction with softer shoulders for extra grip,
                                                                                                while the front tire is a single compound. The secret
                                                                                                to the Dunlop Q2’s extraordinary and predictable grip
                                                                                                seems to be its advanced compound and the Intuitive
                                                                                                Response Profile at the rear, which creates a bigger foot-
                                                                                                print and allows more lean angle than the other tires.
                                                                                                   The Q2s are a significant 2.8 pounds heavier than
                                                                                                the stock tires. They raised the Honda’s axle height by
                                                                                                1.4mm at the front and 1.6mm at the rear; although the
                                                                                                600RR sat a little higher, the steering geometry was
                                                                                                essentially unchanged. However, the slightly taller bike
                                                                                                would arguably give the riders a little extra leverage
                                                                                                when turning in, thereby offsetting any negative effects
                                                                                                of the extra rotating mass. Carding a best lap time of
                                                                                                1:36.3 with Schoenewald at the controls, the Q2s were
                                                                                                almost five seconds per lap quicker than the stock tires.
                                                                                                   McKinley was full of praise for the Dunlops: “I love
                                                                                                these tires! I found them very confidence-inspiring. I
                                                                                                was able to ride comfortably at my limit, yet they were
                                                                                                predictable and stable throughout the corner.”
                                                                                                   Schoenewald felt equally at home on the Dunlops and
                                                                                                said “I liked these tires, and felt very confident with them.
                                                                                                The front was stable, turn-in was excellent, and the tire
                                                                                                held its line perfectly. Leaned over on the brakes—even
                                                                                                over bumps—the tires stayed planted. Overall, steering
                                                                                                input was minimal and once turned the bike felt like it
                                                                                                was on rails.”

                                64   U LT I M A T E M O T O R C Y C L I N G   •   AUGUST 2010
                                                                                                                              >> MICHELIN POWER PURE
Michelin Power Pure
   French tire-maker Michelin was the first manu-
facturer to develop dual-compound tires, and the
new Power Pure tires claim that the soft compound
rubber comes in at earlier angles of lean. The Pures
incorporate Michelin’s Light Tire Technology, which
reduces weight without sacrificing tread depth, and
saves a dramatic two pounds in weight compared to
its rivals.
   The Michelins were the only tires tested that
weighed almost exactly the same as the Original
Equipment. In theory, with less rotating mass, they
should have offered nimbler handling than the oth-
ers, but it did not work out that way. The Pure’s
lightweight carcass had too much flex, causing it to
understeer; the Michelins also made the Honda a
little nervous.
   Lapping with a best time of 1:38.4, Schoenewald was
ambivalent toward the Michelin Power Pures, feeling
that they were grippy and competent over bumps, but
he complained that “the bike wandered and wouldn’t
hold its line. I frequently found myself on the outside
part of the track. Initial turn in was good; the tire felt
stable and didn’t slide, but it just wouldn’t hold its line
without increased effort.”
   McKinley found the same problem: “This tire had
good grip, but it was hard to keep a line and the tires
felt squirrelly, but not from a traction perspective. The
tire was very light to steer, so I lacked some confi-
dence in the front. These tires may require a more
deft hand than I have.”

Pirelli Diablo Rosso Corsa

                                                                                                                              >> PIRELLI ROSSO CORSA
   Pirelli has been the original spec tire in World
Superbike racing for some six years now, and have
used it as their personal R&D lab. According to WSBK
owner Paolo Flammini, Pirelli has “done a superb
job and delivered far more than we asked.” Like the
Dunlop Q2s, the new-for-2010 Diablo Rosso Cor-
sas have a single compound front. However, the dual
compound rear tire has Pirelli’s SC2 race-compound
on the shoulders. Utilizing their proprietary Enhanced
Patch Technology (EPT), Pirelli claims an enlarged and
“optimized contact patch at any lean angle on street
and racetrack.” Similar to the Bridgestones, they use a
steel belted carcass.
   The Rossos were 1.2 pounds heavier than stock and
they raised the rear axle height by a whopping 5.3mm
but the front only by 0.8mm, which certainly reduced
the rake at the front end considerably. But, despite the
change in chassis geometry, without a doubt the Pirellis
gripped well and were fast without being nervous.They
posted a decent lap time of 1:36.5—a dramatic 4.5 sec-
onds per lap quicker than the stock tires.
   Schoenewald said, “These tires worked well, but the
problem was I didn’t have much feel with them, mak-
ing me less confident to push. They didn’t do anything
wrong—I liked them grip-wise and they were stable
in corners—but they were a little sensitive over the
bumps.” McKinley concurred: “These tires were so
much better than stock. They gripped well, but they
felt stiffer and a bit less compliant. They were also a
little bumpy.”

                                                              AUGUST 2010   •   U LT I M A T E M O T O R C Y C L I N G   65
Conclusion                                                         It was interesting that our two testers, with       is too light, it can upset the suspension by not
   When the tires on your sportbike need                        different levels of track experience and an            providing enough resistance to bumps, and it
replacing, any one of these four replacement                    almost 15-second disparity between their lap           reduces the gyroscopic effect of the wheels,
tires will be a marked improvement. However,                    times, generally agreed on how each set of tires       making the bike less stable. Make the tires too
tire performance is not just about the amount                   felt. Clearly, one does not have to be a racer or      heavy, and the tires can overwhelm the suspen-
of grip it generates. It is also about how the tires            super-fast rider to notice the difference in feel      sion in bumps and it can be hesitant to change
feel when the bike turns into a corner, how                     between these tires.                                   direction. It is all about balance, and in this test,
much they transmit the bumps through to the                        The issue of tire weight is a fascinating sub-      of the five pairs of tires, the heaviest clearly had
chassis, how they feel on the brakes, whether                   ject. Logic and experience tells us that, for          the balance spot on.
you can hold your chosen line throughout the                    sportbikes, lighter-is-better.Yet, in this test, the      In last place, were the OE tires. The best
corner, and, if you are really pushing hard, how                opposite proved to be true. Certainly, there is        things we can say about them is that they
they feel once their grip starts to let go.                     a sweet spot in tire and wheel weight. If a tire       are decent and come with the bike, but they

66   U LT I M A T E M O T O R C Y C L I N G   •   AUGUST 2010
are certainly not your best option for high-    were divided in their opinion, with Schoe-            Changing the chassis geometry the least,
performance riding.                             newald slightly preferring the Michelins and       the Dunlop Sportmax Q2 maintains its line
   The Bridgestone BT-016 finished fourth,       McKinley giving his nod to the Bridgestones.       through corners, turned most predictably,
beating the best OE lap time by two sec-        The biggest complaint was the nervousness of       handled bumps well, and gave good feedback
onds, and are clearly superior to the stock     the Michelins and their inability to hold a line   in all situations. Additionally, the Q2s showed
tire. They work well within a certain range,    through the corner, which was not caused by        the least wear at the end of the day. The Q2
but are less competent at the edge of perfor-   lack of grip.                                      was a little faster than its closest competitor, an
mance on the track.                                The Pirelli Diablo Rosso Corsas came in         undeniably important statistic for performance
    The Michelin Power Pure tires finished       second, a full 1.8 seconds quicker than the        tires, but most importantly it was the tire that
third, a blink faster than the Bridgestones,    Michelins. The Rossos gripped well, but            gave the testers the most confidence. By both
but still some two seconds a lap down on the    lacked feel—a difficult handicap for a rider        subjective and objective standards, the Dunlop
Dunlop Q2s. Schoenewald and McKinley            to overcome.                                       Sportmax Q2 is our clear winner. <<

                                                                                                   AUGUST 2010    •   U LT I M A T E M O T O R C Y C L I N G   67

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