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      07-30-2012, 08:16 AM   #1
str8shot
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Michelin Pilot Super Sport tire pressures

Any one use these tires?

I have 255/35/18 and 225/40/18.

@ 38 psi in the front, I was folding the tires over almost to the point of touching the rim to the ground.

Also, gobs of understeer. I'm not a huge fan of these tires so far.

Ran only middle of the pack @ autocross yesterday.
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      07-30-2012, 08:39 AM   #2
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I run 42 psi front and 45 psi rear for autocross and daily driving. Yes, the sidewalls are very flimsy but at high pressures you're fine. I have the same sizes too.

I keep the rears at 45 mostly for fuel economy and to allow for power-induced oversteer but you could probably do 38-40 psi for autocross if you want a little more grip.
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      07-30-2012, 09:51 AM   #3
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For track use I put mine at 33-34 cold. You'll roll the tires over regardless of brand if you don't have camber plates. Gobs of under steer is what this car does with no modifcations. Even with 2.5 degrees you'll still roll over and scrub the outer edges of the tires. I'm going in next week to add more camber.
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      07-30-2012, 10:05 AM   #4
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For autocross there are so many factors that affect tires that you really have to play around with them and monitor after every run. Use your morning session to fine tune your afternoon session. At an auto-x last month I started afternoon session at 35 front and 37 rear (I was 39 and 41 in the morn) and as they heated up they came to life with my second to last and last lap dropping nearly a full second compared to my first two. I ended up third in class (full stock). Yesterday I had a much different experience and two of the key factors was a much different surface (black top and very slippery) and much longer intervals between runs. I never felt I got the tires up to temp and never had the tires above 41 psi. Needless to say I ended up 7th but my times held at 51 seconds all day with my last lap being the fastest and clean. In hindsight I might have gone 38 front and 40 rear just because the wait between runs was so long. I am not sure what level autocrosser you are but in speaking with the guys I run with who usually battle for FTD, they were all shocked when I mentioned 39 and 41 psi to start cold and suggested I decrease the psi (from my autox last month). I hope this helps, I have never been on Direzzas, but I thought these tires were amazing compared to the RFT Bridgestones.
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      07-30-2012, 10:17 AM   #5
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Quote:
Originally Posted by Focusedintntions View Post
For track use I put mine at 33-34 cold. You'll roll the tires over regardless of brand if you don't have camber plates. Gobs of under steer is what this car does with no modifcations. Even with 2.5 degrees you'll still roll over and scrub the outer edges of the tires. I'm going in next week to add more camber.
I've got Vorshlag camber plates installed. I guess I could try running more camber at the track, but I believe they're dialed in pretty good by the PO.
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      07-30-2012, 11:36 AM   #6
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Everything i've read/heard/been told by the internet and my race shop and other track junkies is that bmw's love/need a lot of camber. It's not uncommon for the full race cars to be at 4 degrees or more. I'm going to try 3 degrees...which is about as far as I'm willing to go considering I DD the car.
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      07-30-2012, 12:07 PM   #7
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Quote:
Originally Posted by Focusedintntions View Post
Everything i've read/heard/been told by the internet and my race shop and other track junkies is that bmw's love/need a lot of camber. It's not uncommon for the full race cars to be at 4 degrees or more. I'm going to try 3 degrees...which is about as far as I'm willing to go considering I DD the car.
Mine is now -3.2 with 1/8" toe out for track, and -1.2 with zero toe for street. Takes 30 seconds per side to adjust.
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      07-30-2012, 10:59 PM   #8
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Quote:
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Mine is now -3.2 with 1/8" toe out for track, and -1.2 with zero toe for street. Takes 30 seconds per side to adjust.
30 seconds? It takes me forever to get it right. I drive up on ramps, jack up the front, loosen the 3 nuts (the one under the antiroll bar is annoying), move the strut over then slowly tighten the 3 nuts while holding the strut still (and it always moves out of position)... It takes me 30 MINUTES! What am I doing wrong?
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      07-31-2012, 05:29 AM   #9
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Quote:
Originally Posted by e82n54 View Post
30 seconds? It takes me forever to get it right. I drive up on ramps, jack up the front, loosen the 3 nuts (the one under the antiroll bar is annoying), move the strut over then slowly tighten the 3 nuts while holding the strut still (and it always moves out of position)... It takes me 30 MINUTES! What am I doing wrong?
I adjust my camber plates for track or street while I'm swapping my track wheels and brake pads on or off before or after a track event. So I didn't count the time jacking up and removing the wheel because I was already doing those things.

So the additional thirty seconds is just loosen the nuts, slide the strut with a screwdriver, and tighten the nuts while holding it in place with the screwdriver. It doesn't sound like that's any different from what you're doing.
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      07-31-2012, 06:45 AM   #10
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Thanks. Glad to hear i'm doing it right. I can't imagine swapping pads before and after each event. That's a lot of work.

By the way, I used 38 front and 42 rear pressure at my last HPDE event (not autocross) with my PSS tires and was happy with that, but I have vorshlag camber plates, and I'm a novice track driver.
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      07-31-2012, 09:20 AM   #11
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Quote:
Originally Posted by e82n54 View Post
Thanks. Glad to hear i'm doing it right. I can't imagine swapping pads before and after each event. That's a lot of work.

By the way, I used 38 front and 42 rear pressure at my last HPDE event (not autocross) with my PSS tires and was happy with that, but I have vorshlag camber plates, and I'm a novice track driver.
The whole operation for wheels, pads and camber takes me one hour. I get to sit down for a minute when I'm swapping the pads, so that's probably my favorite part.

With PSS, I kept my hot pressure at 38 all round. So for autocross, I guess I'd make my cold pressure 38.
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      09-27-2012, 08:06 PM   #12
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These numbers are Celcius and Hot temperature, right? 38 would be rolling over the sidewall crazy unless there's 3 degrees+ of neg camber...

I am at 1.5 neg camber front, 1.9 neg camber back... I ran at ~42 hot for a bit the last time i tracked. Got a big track coming up at The Ridge. Still comtemplating what pressure to run the PSSs at...
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      09-28-2012, 12:24 AM   #13
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Quote:
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These numbers are Celcius and Hot temperature, right? 38 would be rolling over the sidewall crazy unless there's 3 degrees+ of neg camber...

I am at 1.5 neg camber front, 1.9 neg camber back... I ran at ~42 hot for a bit the last time i tracked. Got a big track coming up at The Ridge. Still comtemplating what pressure to run the PSSs at...
Celsius? I think you mean PSI (pounds per square inch). I had my tires at 38 psi when hot, which means about 31 psi when cold. I've noticed excessive wear at outer shoulders of front tires so I'll try increasing the pressure next time. I don't know how much though. I'll try 42 psi hot.
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      09-28-2012, 04:48 AM   #14
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Crap. Yeah. I meant psi. Thx for the correction. You can tell I need to sleep more....
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      09-28-2012, 06:38 PM   #15
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i ran 38 to 39 hot at last weekends autocross in 100 degree weather with not much roll over at all. then i tried 36 hot and it did start to roll over. this is with stock camber.
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