Bimmer Retrofit
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Tracking, Autocrossing, Dragstrip, Driving Techniques > Autocross Tire Pressure Questions

Thread Tools Search this Thread
      09-25-2013, 10:33 PM   #1
Private First Class
mmurray's Avatar
Drives: '06 330xi
Join Date: Feb 2013
Location: South Jersey

Posts: 103
iTrader: (0)

Autocross Tire Pressure Questions

As I've learned, a little background goes a long way - On advice from my first few autoX events, I was running slightly higher tire pressures than factory recco (around 4 psi higher up front, plus an extra few for 6psi in the rear - the idea being that I'd get some oversteer back on my XI with the difference, so I was told).

As the season progressed and I started getting consistent, I began to see the effects of a cool/ warmed/ hot/ and overheated tire on my times throughout the day. Best runs were on warm days in the afternoon of split sessions (warm but not gone - thinking of buying a sprayer, will that help?).

The real issue I'm experiencing now is a LOT of sidewall roll on the fronts. I'm running stock staggered 225/40-18, 255/25-18 Bridgestone RE760s (RTA) and have seen marks come to within 3/4" of the wheel itself (pressures were good, checked with a gauge between runs, and against a compressor at the break). I even started pushing my psi limits in hopes of compensating, but no luck.

Suggestions have been to wrap more 255s over the front wheels to square up, but I'd like to explore other options before making that jump with my DD.

Any ideas/ suggestions/ advice? Thanks
Keep right, except to pass. // Mystic 330xi 6MT - ZSP/ZPP/ZCW
mmurray is offline  
Reply With Quote
      09-25-2013, 11:48 PM   #2
will.c's Avatar
Drives: E46M
Join Date: Mar 2011
Location: Central Jersey

Posts: 538
iTrader: (5)

Those tires have soft sidewalls, so that's not surprising. What pressures exactly are you running?
will.c is offline   United_States
Reply With Quote
      09-26-2013, 10:35 AM   #3
Drives: 335i LCI
Join Date: Feb 2008
Location: Home

Posts: 808
iTrader: (1)

Do not compensate for a soft sidewall with tire pressure, add camber instead if you are rolling the sidewall that much.

Pressures I run 2.3 front (OEM) and 2.5 rear (less than OEM)
D_o_S is offline  
Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -5. The time now is 11:34 AM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST