when I get new tires
#1
07-25-2009 | 07:41 PM
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Joined: Dec 2008
Posts: 164
From: LA area
when I get new tires
I will be getting a high performance variety w/ a max pressure of 50. In that case, should I inflate them to the recommended 32 or the tire's max 50? Or should I go somewhere in the middle at like 41-45?
#3
07-27-2009 | 10:31 AM
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Joined: May 2006
Posts: 18,398
From: Wisconsin
Your starting point would be the 32psi from the sticker in the doorjamb. Adjust from there based on wear & contact during cornering.
Make a chalk mark from the tread down over the sidewall. Take a couple corners then look how far down the chalk is rubbed off. Adjust so it doesn't rub off beyond the shoulder.
Similar but better method (if you have an optical pyrometer) is to measure the temperature profile from the tread down to the sidewall.
If you adjust pressure based on really hard cornering, be aware that pressure might not give you very good tread life.
Make a chalk mark from the tread down over the sidewall. Take a couple corners then look how far down the chalk is rubbed off. Adjust so it doesn't rub off beyond the shoulder.
Similar but better method (if you have an optical pyrometer) is to measure the temperature profile from the tread down to the sidewall.
If you adjust pressure based on really hard cornering, be aware that pressure might not give you very good tread life.
#5
07-27-2009 | 04:49 PM
Registered User
Joined: Jan 2007
Posts: 4,322
From: Brandon, MS
Personally (no recommendations here), I stick with a little under the max psi rating on the tire. The more tire pressure, the better the gas mileage. But if you overinflate, the tires will wear out faster, just like if you underinflate.
example: my tires say max PSI is 44. I air them up to about 39 or 40 PSI.
example: my tires say max PSI is 44. I air them up to about 39 or 40 PSI.
#6
07-27-2009 | 05:26 PM
Super Moderator
Joined: May 2006
Posts: 18,398
From: Wisconsin
Another method for DD cars, you can go by treadwear. I measure the tread depth (center & shoulders) and as soon as I begin seeing the center wearing different than the shoulders, I adjust the pressure. In most cases that gives me higher pressure than the door-jamb sticker. But you always have to stay within the max pressure on the tire sidewall.
It all depends on your goal.
Best gas mileage?
Best tire lifespan?
Best autocross time?
Smoothest ride?
It all depends on your goal.
Best gas mileage?
Best tire lifespan?
Best autocross time?
Smoothest ride?
#7
07-28-2009 | 12:52 AM
Been Around A Long Time Member
Joined: Jun 2007
Posts: 7,381
From: St. Paul, MN
My tires max out at 50 and I inflate them to 46, since the air pressure increases as the tires heat up. The max I've seen the pressure go from lots of driving on a hot day is 48 though. They wear evenly and don't have a saggy sidewall either.
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