So I finally got out to the track a few weeks ago. I got a chance to scrub in those parts of my tire that I was not using on the street. It was a great experience and a lot of fun.
When preparing for the track day, I checked my tire pressure in advance. I set the front to 32 and the rear to 36. After the track day, I could see some weird looking wear patterns on the tires. The rubber had been pushed around on the tire and there were little rubber nubs at the ends of the wear area on the tire. I've included a pic. Sorry the pic sucks, but all I had was an iPhone camera in the parking garage this morning. Hopefully you can make something out of it.
I have a 09 696 BTW. A friend suggested that probably set my pressure too high or too low.
(http://img63.imageshack.us/img63/1699/photo1xh.jpg)
I would guess they heat up and wear this way, especially if they are soft tires.
Looks normal for a track day on sport tires.
It's hard to tell from the pic, but a lot of rubber has been pushed and is lumped up in places. Is that normal for a track day?
Quote from: pompetta on June 30, 2010, 04:59:41 AM
Looks normal for a track day on sport tires.
Quote from: 696DCRider on June 30, 2010, 04:50:02 AM
The rubber had been pushed around on the tire and there were little rubber nubs at the ends of the wear area on the tire.
It's exactly that the rubber has been pushed. That's totally normal for a set of tires that have been to the track - so don't worry, wear it as a badge of honor.
Regarding the pressure - you could probably shave a couple pounds off for track use. The tire will run warmer, so be softer and more grippy (unless it gets too hot...). The trade off is that you'll get more wear...
That's a really high pressure for a track day. The heat can add four or more psi depending on the tire type. I have a lot of rubber build up on the sides of my tires after a track day when my pressures are off.
a couple of notes...
That rhythmic balling of the rubber tends to show a lack of rebound in the rear suspension, however, with the tire pressure so high, it could easily just be that the tire carcass was too stiff to get to temp and allow the rubber to work.
You have to set your pressures cold, and adjust them hot to make it work. no more than a 10% rise in pressure is a good rule to follow, but of course, ask your local race tire vendor what to run.
Will
+1 on tire pressure being too high. Next time you go to the track search around for the best pressure for your specific tire. It should be in the 20s.
what Will said ;)
Welcome to the voodoo world of suspension.
Great info in this vid from Dave Moss:
http://www.onthethrottle.com/content/view/642/73/ (http://www.onthethrottle.com/content/view/642/73/)
Isn't 20 psi a bit too low?
Your pressures are way too high. As mentioned, set them cold (before you go onto the track). Find the vendor that sells your brand, and ask them about your pressure. They have a chart that they can look up. It will be more difficult to get an exact number for your street tires, but the vendor will know what pressure to run. It will be somewhere in the high 20s cold.
Thanks for your responses. I do think I had it a little too high. I had never been to the track before, so I didn't really realize I should be setting my tires lower than I would on the street. So does anyone else with the 696 have a good recommendation on tire pressure on the street and on the track. I have been running at 32/36 on both. I honestly don't even know if that is a good pressure for the street. That is lower than the sticker says though. My buddy told me that the recommended pressure is a bit high.
It depends on the tire. Like others have said...find the tire vendor for your make and ask them at your next trackday. I can tell you what I run...but that doesn't mean it is right for you.
Street - Michelin Road 2cts: F 32 / R 34 (or somewhat close to that)
Track - Pirelli Super Corsa Pro: F 28 / R 26
Quote from: Triple J on June 30, 2010, 09:39:00 AM
It depends on the tire. Like others have said...find the tire vendor for your make and ask them at your next trackday. I can tell you what I run...but that doesn't mean it is right for you.
Street - Michelin Road 2cts: F 32 / R 34 (or somewhat close to that)
Track - Pirelli Super Corsa Pro: F 28 / R 26
My BT-16`s on my 750 were 27 cold 28 hot, rear 26 cold 29 hot. I`m not that fast and the bike is slow so they didn`t heat up a lot like some other bikes. The wear looked good throughout the day.
I've never been on the track, but I did get my tires to look like that after a really hot day riding the roads north of Napa a few years ago. And yes I did wear it as a badge of honor (even though that RC-51 took me to school...twice!)
Quote from: Triple J on June 30, 2010, 09:39:00 AM
Track - Pirelli Super Corsa Pro: F 28 / R 26
I race an sv650s with those tires... 120/160s... and F31 / R27 is what our tire guy recommends HOT. So I usually am about 4 below that starting. (I could be off a bit... as the Pirelli guy is there every day and I tend to ask him each morning, it changes a bit depending on the condition of the track and the weather.)
For my duc on Bridgestone bt003 RS I find that 31F 29R works great. (track)