Went Autocrossing and have questions

BeAmW335i · 08-03-2008, 07:57 PM

I went Autocrossing with the local Corvette club in my stock 335i coupe. My tires were set to 38psi cold all around. After the first few laps (yes, we had 10 laps), I noticed that my car started sliding around coming out of the turns, and I was also fighting the car during the turns (front tires look worst than the rears). After all the laps were over, one member suggested that I lower the tire pressure after the first few laps, because it was probably in the lower 40s. I didn't actually have a guage with me to check it.

I'm going back in 2 weeks, and would like to find out what was causing this problem. Maybe I was going too fast into the turn...I dunno.

Thank you.

longodj · 08-03-2008, 08:04 PM

Quote:

Originally Posted by BeAmW335i

I went Autocrossing with the local Corvette club in my stock 335i coupe. My tires were set to 38psi cold all around. After the first few laps (yes, we had 10 laps), I noticed that my car started sliding around coming out of the turns, and I was also fighting the car during the turns (front tires look worst than the rears). After all the laps were over, one member suggested that I lower the tire pressure after the first few laps, because it was probably in the lower 40s. I didn't actually have a guage with me to check it.

I'm going back in 2 weeks, and would like to find out what was causing this problem. Maybe I was going too fast into the turn...I dunno.

Thank you.

Keep the fronts ~2-3psi higher than rear. Get a gauge for sure, $7 at Pepboys :-P

nicknaz · 08-03-2008, 10:49 PM

Yes, I agree the tire pressure could be too high. I'd start off with 32psi cold. Most people increase the tire pressure to try and prevent sidewall roll over, and if you have run flat tires, r compound tires, or a street tire with mega stiff sidewall (RE01R, RT615, etc) you don't need high air pressures. (Also, in all tires, high pressure decreases available grip because the contact patch is decreased.)

Also, you could be trying to go too fast in the slow sections. You should ask an experienced person to ride with you and give you pointers.

Best of luck!

08-03-2008, 07:57 PM	#1
BeAmW335i Private First Class 27 Rep 184 Posts Drives: 2007 BMW 335i Join Date: Dec 2007 Location: USA iTrader: (1)	Went Autocrossing and have questions I went Autocrossing with the local Corvette club in my stock 335i coupe. My tires were set to 38psi cold all around. After the first few laps (yes, we had 10 laps), I noticed that my car started sliding around coming out of the turns, and I was also fighting the car during the turns (front tires look worst than the rears). After all the laps were over, one member suggested that I lower the tire pressure after the first few laps, because it was probably in the lower 40s. I didn't actually have a guage with me to check it. I'm going back in 2 weeks, and would like to find out what was causing this problem. Maybe I was going too fast into the turn...I dunno. Thank you. __________________ 2007 335i Coupe Black Sapphire Metallic \| Coral Red \| Gray Poplar Wood Trim \| Sports Package \| Premium Package
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08-03-2008, 10:49 PM	#3
nicknaz Lieutenant General 3187 Rep 10,509 Posts Drives: C6Z Join Date: May 2008 Location: NorCal iTrader: (0)	Yes, I agree the tire pressure could be too high. I'd start off with 32psi cold. Most people increase the tire pressure to try and prevent sidewall roll over, and if you have run flat tires, r compound tires, or a street tire with mega stiff sidewall (RE01R, RT615, etc) you don't need high air pressures. (Also, in all tires, high pressure decreases available grip because the contact patch is decreased.) Also, you could be trying to go too fast in the slow sections. You should ask an experienced person to ride with you and give you pointers. Best of luck!
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