“THUNDERHILL July 31, 2011
BRIDGESTONE BATTLAX R10 DOT RACE TIRE TEST
- Rear tire 190/55 x 17 Medium TYPE 3 compound
- Front tire 120/70 x 17 Medium TYPE 3 compound
AMBIENT TEMP: 97 degrees F
TEST BIKE 2009 Yamaha R1, mileage 7650
CHASSIS AND SUSPENSION SETTINGS
OEM fork with Ohlins 25mm internals, 1.0kg springs, C4 R3 valving
- Fork height +5mm showing
- Fork preload 10 turns in
- Fork rebound 12 clicks out
- Fork compression 5 clicks out
- 295mm, no spacer, 11kg spring
- 8mm free sag, 25mm rider sag (rider 193lbs no gear)
- preload on line #6
- low speed compression at 15 clicks out
- high speed compression at 15 clicks out
- rebound at 20 clicks out
SESSION 1 (8 laps):
- scrub tires in
- calibrate gauge with tire vendor's test port
- Chicken Hawk warmers on high for 45 minutes
- Set rear at 30psi, front at 32psi off the warmers
- Set at 32psi hot (off the track) rear and 34psi hot front at the end of session 1
My initial impressions are centered on the fact that this tire has a completely different roll profile that its predecessor. The chassis wants to be on the edge of the tire very quickly and once lean is initiated it gets right to the edge. I personally find that to be a huge bonus, even though the chassis is a mile off for handling right now.
Once on the edge of the tire, the grip feels very similar to a Pirelli slick in that the carcass has more flex to it than the previous 003 Pro, especially on the outer edge. This can be a little disorienting at first if you don’t know what is happening and it might feel as though the bike is wobbling a little on trail braking and acceleration. Trust the tire!
On another test I will play with tire pressure to see how that flex can be mitigated.
Session 2 (8 laps)
GOAL: chassis review for better turn in, stop running wide on corner entry and exit running consistent 2:02 lap times
- positive change by rear ride height increase, better turn in (still have to hold it on line with bar pressure) but fading wide on exit at 25% throttle
- front end too stiff & riding too high in the stroke
- front tire wear showing rebound too slow
- front tire tear from too low hot pressure (track now 115 degrees F)
- fork preload to 9 turns in
- fork rebound to 16 clicks out
- fork compression to 7 clicks out
- shock ride height + half a turn
- front pressure off the warmers 34psi hot
The tires grip very well on trail braking and the front can be pushed really hard much like the Bridgestone slick front. Therefore for a point and shoot riding style that is mandatory for the 1000’s, the front really is excellent in giving great feed back. The carcass flex is still there, but that helps soak up some of the high speed bumps to mute the severity of their impact, so that’s a compromise I am willing to live with.
SESSION 3 (6 laps)
GOAL:- continue with geometry work re turn in and front end feel, and review shock settings re drive off the corner (shock preload too soft?).
- positive improvement of front rebound tear
- improved turn in, but still needs firm bar pressure mid corner for corrections
- zip tie 10mm from the bottom
- rear tire wear showing compression too stiff
- fork preload + ½ a turn in
- shock HSC 21, LSC 21
- shock ride height lowered 2 faces
note tire tearing behind sipe/tread pattern an the outer edge and rebound lip on leading edge indicating rebound is too slow.
The changes made in this session yielded much better results with tire wear overall. There’s still the oddity of the tire balling up on the cold side to figure out (left hand turns at Thunderhill are slow, off camber and/or downhill so throttle use is done so with great care). Rear tire pressure may too low given track temps and lap times creating too much carcass heat. If that were the case, you would expect larger balls of rubber on the left side of the tire but there are very few. That may be due to lean angle.
SESSION 4 (8 laps)
GOAL:- work on rear shock squat at 30-45% throttle, to finish a corner on line by starting with 1.5 turns more shock preload
- positive corner exit, held line
- improved rear tire wear as graining pattern appeared for the first time today
- forks possibly too low with too much brake dive
- took out 3 x 1/4 turns in succession, removal of ½ turn optimal
It is always nice to be able to get on the throttle with confidence, and this session allowed that opportunity at last. The R1 is very strong coming off the corners anyway, but with the shock changes made it could really get the R10 to bite and give excellent drive grip off the corner. There is such a thing as too much grip, but we didn’t get to that point. It is nice when you have a smile opening the throttle rather than an intense focus keeping the bike on line!
SESSION 5: (8 laps)
GOAL:- improve fork dive under initial hard braking in a straight line by adding ½ a turn of preload an 1 click of compression
- much improved initial dive
- less rear wheel side to side sliding under heavy straight line braking
- forks possibly too low in the triples
- low speed rebound wear evident on both sides of the front tire
For some riders, having the rear wheel move around is just fine – in fact it may be mandatory so they can relax. I don’t mind a little fish tailing but it is a little off putting when it starts immediately. Proper technique for the test is of course critical: apply the brakes, make the weight transfer occur and then substantially increase brake pressure. If rebound is too slow as per tire wear, it will amplify that fish tailing as the fork is held down in the stroke and poor fork action will cause deflection over high speed bumps. The tire gripped really well on the front staying perfectly in line but as rebound was opened up, I could feel the front end work the stroke again rather than sit in one position.
NOTE: graining now on both sides of the rear tire! We have the wear pattern we need to see.
- remove 3 clicks of rebound, 1 per lap after 3 lap warm up
SESSION 6 (8 laps)
GOAL:- clean up the low speed rebound tear on the front tire without sacrificing geometry when blending trail braking into positive throttle
- remove 1 click of rebound at a time starting at 14 to 18 clicks out
- 16 was the best setting otherwise the fork would pogo on corner entry and on trail braking
SESSION 7 (8 laps)
Free ride so finish the day with no focus on suspension – only on reference points and pace to ensure laps times of 2:00 to 2:02 remained consistent
Note that with the track at its hottest, the left side of the rear tire balled up far more
than before bringing into debate the rear tire hot pressure from earlier in the test.
- front tire rebound tear cleaned up
- rear tire graining pattern – perfect wear
- 34 hot front and 32 hot rear were appropriate tire pressures given ambient and track temps but more hot pressure testing needs to be done
- rear tire on the wear bars on the left side
- total mileage 162 for the day
- height +5mm
- preload 9 turns in
- rebound 16 clicks out
- compression 6 clicks out
- length at 295 +2 turns of ride height
- preload at line 6.5
- high speed compression at 21 clicks out
- low speed compression at 21 clicks out
- rebound at 21 clicks out
These new R10’s are a big step up from the 003 Pro’s in roll profile, grip and feedback. As you have read in this and other tire tests we have done (and the same is true every time you change tires sizes or brands or compounds), chassis and suspension changes are mandatory to get the best out of the tires in terms of grip and longevity and there’s no shortcut to this process.
Clearly the rear compound is a race weekend tire offering tons of grip and no fade on the grip after 160+ miles - but as a track day rider, you might see 2 days from the rear. The front tire is much more durable so I would imagine 2 rears to one front would be the norm. Bridgestone does offer a harder T2 compound rear tire for those who are willing to trade a little grip for longevity!
I do want to play with tire pressures next time around to see if the flex can be optimized for better feel on trail braking and acceleration where the torque of the R1 really works the carcass. A manufacturer’s recommended pressure is exactly that but it doesn’t take into account rider skill set, track temps and engine horsepower and torque.
I am impressed – nice job Bridgestone engineers and testers!”
Dave Moss – Dave Moss Tuning