|
Post by SOHCman on Sept 18, 2007 13:46:49 GMT -5
A general question for all you experienced rally drivers.
Should tires be "overinflated" for sustained high-speed driving?
Old school tech says "yes" about 10%.
New tires, manual doesn't say anything.
I ask because my last set of BFG tires lasted 42,600 miles.
They were maintained at the recommended 35 PSI and they wore out in the middle!
I would hydroplane on mist...
Now two questions come to mind:
1. Were the tires too soft and the high speed driving caused them to "balloon" out and wear in the center?
2. Were the tires too hard and the high speed driving caused them to wear in the center and not evenly?
Should I go up to 38 or down to 32?
Should there be a f/r differential like with the Chevy Corvair (used to run 20/30 f/r)
The tires are rated for 112MPH.
Been there, done that.
SOHC
|
|
|
Post by skimobile on Sept 18, 2007 14:46:49 GMT -5
Are you measuring cold tire pressure. A normal rule of thumb for track days is ~5psi over stock dealer recommendation to start for better cornering/ tire roll resistance, assuming tires/wheels are still stock and adjust from there. 42k/mi on tires doesn't sound too bad to me
|
|
|
Post by Sean on Sept 18, 2007 14:49:07 GMT -5
I run 10lbs over recommended. Tires heat up after 6 hours of driving lol. That can cause the pressure to lower.
|
|
|
Post by SOHCman on Sept 19, 2007 6:42:04 GMT -5
Well, they are supposed to be good for 60k.
Judging from the outside edges, I'd say mine could have gone at least 50-55k if the centers weren't bald.
I'll bump my normal pressure up to 40.
Thanks for the info
|
|
|
Post by ScrapinSTi on Sept 21, 2007 9:18:05 GMT -5
I run 10lbs over recommended. Tires heat up after 6 hours of driving lol. That can cause the pressure to lower. Other way aroudn... The more driving, the more they heat up and expand.. When I start an autocross, I air up to 40psi or so... Then throughout the day, I drop my pressures back to 40psi because as it warms up & the tires warm up, the pressures go up... And SOHCMAN if you wore in the middle of the tires, you are overinflated.. Go down in your pressures.
|
|
|
Post by Sean on Sept 21, 2007 14:00:14 GMT -5
Interesting. I definitely lose pressure after long rides. Could it be because I run low profile tires? I don't lose pressure any time other than long trips (500+ miles).
|
|
|
Post by ScrapinSTi on Sept 22, 2007 7:27:40 GMT -5
If you leave the tires alone does the pressure come back up?
|
|
|
Post by Laser Star USA on Feb 28, 2008 2:56:41 GMT -5
I run my Kumho SPT's (VR's) at 42psi for normal driving and 45psi on the tracks so 7-10psi is where Im at..depending on driving style.
|
|