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      08-29-2012, 11:47 PM   #1
mrh335
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Pilot super sport pressure

Getting ready for a first track day on my 2011 E90 M3 with competition package. I have Michelin Pilot Super Sports 275/35 R19 and 245/35 R19 (stock sizes).

Does anyone have some good recommendations for pressures to run to keep from destroying the tires and maximizing enjoyment?

What is the proper procedure to use for checking tires and knowing when and how to adjust their pressure?

Pressures are normally set cold, but what is the procedure for track days to risk overheating?

I also see it is supposed to be 94F and not sure what affect that will have over normal heat from driving.
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      08-30-2012, 12:19 AM   #2
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If it's your first event EVER, leave it at OEM pressure (what's listed on the door jam) and check after each run session and make sure it's not over 40 psi HOT right after the run session.

There's nothing you can do to "keep from destroying the tires" without increasing negative camber, or learning how to manage your tires and contact patch, which, at your first event, you'll definitely not know how to do.

Lastly, if you have some chalk available to you, you can try and mark the sidewalls to make sure the tires aren't rolling over too much. But if you can't get enough camber in the first place, it's not going to really make that big of a difference. Try and keep the tire pressure in a range where the wear marks come near the edge of the "Bibs" on the sidewall (usually a little Michelin man denoting where the tire wear bars are). If you're up at 40+ psi and it's still completely wiping out the Bibs on the tires, then you're simply pushing way too much slip angle for your own good at this point.

If you've got hundreds of events under your belt, and this is your first event with the M3...You'll know what you need to do within 3 laps. Good luck.

EDIT: If it's not clear to you now, it is IRRELEVANT what your cold pressure is. It's your HOT pressure you need to keep an eye on.
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      08-30-2012, 06:43 AM   #3
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As the Hack said, aim for 40psi hot.

BTW, 275/35 is not a stock size at the rear.
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      08-30-2012, 06:46 AM   #4
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I'd try 30-32 cold, depending on how hard you are going to drive. 30 has worked well for me on AD08's, reaching 38-39 hot.

You could run ~32 cold, come off track, and check pressure. If it's over 40, bleed down to 39.
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      09-03-2012, 08:56 PM   #5
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After a 20 minute first session at the Autobahn CC south course, my off track pressures were 42 psi front and rear with slightly higher pressures on the driver's side.

I bled them down to 40 psi and after the second 20 minute session, they were back up around 41.5 to 42 psi.

I checked the pressures the next morning when things had cooled down in the garage and about 75F out and the pressures read 32/33 in the front and 34.5/33.5 psi in the rear. I started the track session at 34 front and 35 rear (1 psi under the door jam pressures).

I guess next time I will run them even lower when I set them cold and make sure to keep letting air out.

Any other hints or tricks would be welcome.
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      09-04-2012, 08:04 PM   #6
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Quote:
Originally Posted by mrh335 View Post
After a 20 minute first session at the Autobahn CC south course, my off track pressures were 42 psi front and rear with slightly higher pressures on the driver's side.

I bled them down to 40 psi and after the second 20 minute session, they were back up around 41.5 to 42 psi.

I checked the pressures the next morning when things had cooled down in the garage and about 75F out and the pressures read 32/33 in the front and 34.5/33.5 psi in the rear. I started the track session at 34 front and 35 rear (1 psi under the door jam pressures).

I guess next time I will run them even lower when I set them cold and make sure to keep letting air out.

Any other hints or tricks would be welcome.
Hey dude, hope you had fun up at Autobahn, I'm usually up there, who did you run with? I'm running AD08's but the principles are similar and I run the same, around 39-40 hot, and that requires me starting around 30 psi front and 32 psi rear so would definitely think start a bit lower. The next day if I forget to put air back in the tires they could be as low as 28-29 which sets off the sensors. Hope to see you out there sometime, I'll be back up there in October, VIR in September
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      09-05-2012, 12:19 AM   #7
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Quote:
Originally Posted by mrh335 View Post
After a 20 minute first session at the Autobahn CC south course, my off track pressures were 42 psi front and rear with slightly higher pressures on the driver's side.

I bled them down to 40 psi and after the second 20 minute session, they were back up around 41.5 to 42 psi.

I checked the pressures the next morning when things had cooled down in the garage and about 75F out and the pressures read 32/33 in the front and 34.5/33.5 psi in the rear. I started the track session at 34 front and 35 rear (1 psi under the door jam pressures).

I guess next time I will run them even lower when I set them cold
and make sure to keep letting air out.

Any other hints or tricks would be welcome.
Yeah, start at lower psi than 34/35.

On my R-S3, to aim for 38 psi hot (track pressure), I start out at 30 psi cold in the morning (and, monitor & bleed/add throughout the day).
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