khp Posted May 2, 2011 Report Share Posted May 2, 2011 In the quest for trying something new and possibly better, I switched from running Pirelli Diable Supercorsa's to Dunlop D211GP Racer this year. For the Easter trackday/training camp at Autodrom Most, Czech Republic, I put on new tires front & rear for the event. On the recommendation from Steve and Bullet here in the forum, I went for the following combo for my 2008 model YZF-R6: D211 GP Racer (DOT, ie not Slicks). Tires are marked with "MT", "JLB" and "NTec". Front: 120/70 Medium compound Rear: 190/55 Endurance compound (date code 10/week 35) BTW: these tires are "Made in France" - I guess this makes them "UK spec" according to Steve. I followed the advice from the Dunlop Racing webpage (repeated here by Steve): 33 psi front/23 psi rear, hot off the warmers (I used a laser/IR temp gun to verify that the temperature was OK). Tires were warmed for an hour in the morning, and for the last 20 min prior to each succeeding session as advised. Upon returning to the garage after a session, I measured around 65C on the rear and 50-55C (hazy memory here) on the front. Air temperature was 20-25degrees C, all three days - no rain . I didn't check the track temperature though. I experienced no or little traction problems during all three days - except a single very small slide exiting the hairpin when pinning it in 2nd when leaned way over (hey, gotta try find the traction limits, right? ). Combined over the 3 days, I rode approximately 4 hours according to the laptimer. My laptimes dropped from 2:05's on the first day to 1:55:45 in the 3rd & final session of the 3rd day. I must be catching up, 'cause I'm now less than 15 seconds behind the fastest 600cc guy (who's on a Supersport prepped Yamaha-Denmark backed bike, which is wickedly fast), who did 1:41:xx laps The front tire looks excellent, with very little wear. The rear, however, is a different story that I'd like some input on. As it turned out, I did an error on the morning of the first day when setting the pressure on the rear: instead of setting the pressure to 23psi, I set it to 25psi. When the tire started to show significant wear on the second day, we diagnosed it as over-inflation (confirmed first by a suspension/tire expert from one of the bigger race teams, later also confirmed by the pressure gauge). The pressure was then reset to 23psi on the morning of the third day. On the third day, my laptimes continued to drop from 1:57 to 1:55, but the wear pattern did not change. I've attached 3 pictures of the rear. On all three, a band on each side of the tire can be seen where the tire is much more worn (the wear is more easily seen on pics 2 & 3). Also, it seems that the tire likes to have an "edge" or ridge in the wear-band where the wear-pattern changes. In real life, the wear looks more dramatic than in the pictures and I'm wondering much much more life there is in the rear tire. Another guy on a 2008 R6 was running 180/55 Medium GP Racers (yes Bullet, you can get them!) was underwhelmed by their grip and complained about wear, which looked similar to mine. He was running 1:46 laps though The Pirelli Diablo Supercorsa SC1/SC2's run by other riders on R6'es did not exhibit any wear problems. My questions are: Is this wear to be expected? - is the wear "just normal" or caused by the 2psi over-inflation? Are the GP Racers really that sensitive to (incorrect) pressure? Should I be running a different compound? What is that ridge in the wear - compound change? I'm wondering whether a return to the Supercorsas would make good sense from a tire wear/expense point of view, if I'm able to get less/better wear on the Pirellis than on the Dunlops. And a final bonus-question to Steve: a third racer told that she is getting 6+ days out of a Soft compound front tire, which apparently is quite normal for the GP Racer's. Any good reasons to choose or not choose the soft front, if it really lasts that long? I still have a set of Pirelli's with reasonable amount of thread left, so I'm considering to mount them on my rain-wheels in order to do a back-to-back test during a future trackday. Thanks for all and any input, Kai Quote Link to comment Share on other sites More sharing options...
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