Track day tire pressures (Pilot Pures) - Honda RC51 Forum : RC51 Motorcycle Forums
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post #1 of 19 (permalink) Old 04-27-2010, 08:23 PM Thread Starter
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Track day tire pressures (Pilot Pures)

Looking for some opinions from track day RC51 riders...

Just installed a set of Michelin Power Pure tires & did one track day so far,
set at 30/30 psi on my 00 , based on non RC51 rider-racer dude recommendations. I am average / intermediate rider, 195 lbs + suit, riding
average size tracks, no super long straights.
I don't have enough time on this bike to tell if I am running the correct pressures.

Please feel free to provide some input for me.
Also, would you run different pressures when switching to a super smooth freshly surfaced track ?

Thanks !
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post #2 of 19 (permalink) Old 04-27-2010, 10:25 PM
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30/30 may be acceptable for street applications but, if theses numbers are cold tire pressures, they're too high for the track. Use 26F/24R as a base and adjust up or down (in SMALL increments) from there. At 30 PSI in the rear you're not allowing enough of the tire to come in contact with the road surface in the corners.
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post #3 of 19 (permalink) Old 04-28-2010, 05:54 PM Thread Starter
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Yowsa...that's much lower pressure than I was expecting.
The 30/30 I mentioned was infact cold pressure initial setting.
I believe the RC manual calls for 36/42 psi for regular street use. This may be the recommended
pressures for my VFR, but anyway I know the OEM pressures are much higher than what
everyone uses for track riding.

So you recommend 26/24. This may be why it didn't quite feel right at over 30 hot.
Now comes the hard part...from that point on, I am not sure what to do as far as adjusting up or down ? What are the symptoms to look for and what are the correlating adjustments ?. Obviously my suspension settings should come into play at the same time (this bike's suspension has not yet been "dialed in" to any extent. I simply
adjusted my sag then set rebounds to my liking).
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post #4 of 19 (permalink) Old 04-28-2010, 07:55 PM
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Let me back up for just a moment. My bike's suspension has had some major work: Ohlins fork springs (sprung for my weight, 190 lbs. plus gear) and Ohlins Super Bike valving. (The $2300.00 for Ohlins R/T forks just wasn't in the budget. BTW: The RC's stock forks are some of the best OE units in the business. They just need tuning for the track) Rear shock: Ohlins, again with the correct spring for my weight. Then the bike was set up for me (with gear on at the track, between sessions) by Ken Hall of Superbike Italia (www.superbikeitalia.com) out of Chicago. He's an exceptional tuner who I've used for about two years with excellent results. Excuse the commercial, but Ken's that good. He travels with STT to many of their venues in the Mid West and South. I know I'm getting long-winded, but if you're serious about the track then suspension is priority one: Find a good, reputable suspension tuner and spend your money there first. All other changes/additions are secondary. No other mod can affect your lap times (both plus AND minus) as much as suspension, IMO.

Sorry for the sermon. I wish someone had told me when I started tracking my RC, BEFORE I spent money on rotors, pads, Ti exhaust, etc. I really did put the cart before the horse. I'm also running Pilot Race slicks, medium compound f/r. There's absolutely nothing wrong with using DOT race tires. Quite a few guys I know who're faster than me are running DOT's. I just like the POM slicks give me...

Let me take a rest and I'll finish answering your questions...
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post #5 of 19 (permalink) Old 04-28-2010, 11:09 PM
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I read that the Michelin engineer's recommend not dropping the pressures for the track with the Pure's because they rely on air pressure to keep the side walls stiff(told a magazine tester to run the manufacturer recommeded 36/42 psi). I was a little skeptical, but tried going out at 35 front and rear at Barber Sunday just to see for myself. I didn't like that at all so I came in and dropped to 30psi f & r and was way happier. I really liked them after that and noticed I didn't shred them near as bad as the Bridgestone 002's and 003's I ran before.
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post #6 of 19 (permalink) Old 04-29-2010, 02:58 PM
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Chip's point is well taken. I'm not running the Pure's so better ere on the side of caution and run what they recommend. But in response to the second half of your question (now that I'm rested) overinflation results in a smaller contact patch which is already limited from cornering. By limiting the contact patch you run the risk of loosing the front end quicker, the faster you go. Less contact=less grip and traction. Under inflation causes too much contact resulting in higher friction and higher operating temperatures. The tires wear faster and you can't get a good "feel" for the track because of excessive sidewall flex. They start to feel "greasy." There's less of the "quick input leads to a quick response" that you'd get from proper inflation. The end result of both over and under inflation is slower lap times and faster tire wear...
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post #7 of 19 (permalink) Old 04-29-2010, 03:06 PM
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Paisanoracer's recommendations are probably a decent starting point for for "race" tires, but likely too low for "street/trackday" tires.
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post #8 of 19 (permalink) Old 04-29-2010, 09:14 PM Thread Starter
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ChipG
This is the first I have heard of Michelin recommending to keep pressures high on the Pures. So you liked 30/30... what is your suspension set-up ?
You are the first guy I know that is running these tires.
I know Michelin is pitching the high techness & low weight & all, but hype aside, I can't see these being all that different from Pilot Powers...which I ran on my track YZF600 last year at 30/30. I am all for experimenting, but my butt cheeks are clintching at the thought of finding out the hard way on my favorite bike (which I think is heavier than the '96 YZF ?).

Pais
Good advice about spending some effort on tuning my suspension first. Sounds like a smart move. I will ask around for a reputable tuner for my stock set up for starters.

The talk about contact patch...that is precicely what I envision from the start of braking for a corner through corner exit. It's my way of trying to stay as smooth as possible.

Thanks for the feedback guys !
I'm back at the track in a few weeks so I'll let you guys know how it went.
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post #9 of 19 (permalink) Old 04-29-2010, 11:12 PM
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Yes, I was pretty happy at 30/30 psi cold. My front end is re-valved and sprung for my weight, and the shock is stock. I weighed them before I put them on and they are 3.2 lbs lighter than the 003's I replaced them with, but to be honest I really didn't feel a great difference riding.
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post #10 of 19 (permalink) Old 05-10-2010, 08:40 PM
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Just read a review of the Pilot Pures in May's Roadracing World. Gotta tell ya, in my humble opinion, these things are in a class by themselves. After learning what they're about, I'm ready to replace the Qualifiers on my CB919 (street ride). Unfortunately, the Dunlop's only got 800 miles so it'll be a little while...

Last edited by Paisanoracer; 05-11-2010 at 03:50 PM.
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