AARotary

I have 32psi up front and 35 psi in rear. Is this OK for street. What is the general tires pressures are you guy having on your tires?

DamonB

I run 35 all around on the street; I like the fronts a little stiff. At the track that changes everyday...

turborotarypower

are you running those 19" blitz rims still? anyway any plus sizing in wheel and tire combo must have an adjusted tire pressure figure for load carrying. when i use to sell custom wheels and tires i had all my plus sized customers keep inflation to atleast 44psi(alot of people going with +2,+3 and even +4 rim sizes!) if you don't have the right tire pressure,the tires will wear prematurely on the outsides(under inflation) if you cannot get the correct info from the tire shop who did the wheels for you read your tire sidewall and see what max inflation is for the tire when cold(when car has not been driven for many hours)inflate to about 5 psi under this figure because when the tire gets hot the tire pressure increases a few lbs.

AARotary

So base on what you are saying, the max inflation on my sidewall stated 50psi so 44psi should be good right. Anh should I put 44psi on all 4 tires.

HedgeHog

Tire pressure optimization sometimes depend on the brand/model of tires. I run 34-36 psi on my S-02 Pole Positions (245/40-18 & 275/35-18). When i autox them, they go to 42 psi. My Kumho Victoracer v700 (245/45-16) gets 38psi at all corners - there's been reports that sez Kumhos operate better with lower pressure. Hoosiers A3S03 likes to run higher pressure (38-42psi). Sizing should not have any major effect on pressure...although with a super low profile tire, the sidewall is so stiff that if you were underinflated, it'd be hard to tell visually.

If you already run a staggered tire width setup, i would keep front/rear pressures the same...this makes it easier to balance the car. If you want to really figure out a good pressure setting, get a tire pyrometer and measure the inside, middle, outside tire temps after running around in a g-circle. Or the cheap way is to mark the shoulder w/ chalk/shoe polish/white-out. Drive the g-circle again and see if the mark rubs off the tread on the shoulder. If it does not wear near the shoulder, deflate your tire a bit and run again. If it's wearing too much (tire rolling over), inflate it more.

Good luck.

EDIT: PS. Premature wear of the shoulder could indicate alignment problems (too much toe in, not enough camber, etc).

SleepR1

I hope those are hot temps, not cold temps. If those are cold temps, that's too hot for Hoosiers, at least in my experience with R3S03s.

I start with 30 to 32 psi cold, take a few hot laps to get the tires up to temp, and adjust toward 38 to 40 psi HOT.

The last session I was out at Putnam Park (Dec 15, 2001), I let more air out of the fronts, so cold starting pressures were 28 psi front, and 30 psi rear--I have the staggered setup with 8.5 fr and 9.5 rr x 17 SSR Comps, 245/45-17 fronts and 275/40-17s rear. With a full tank of gas, understeer is mild, and increases as the fuel tank empties. I don't let the tank get below 1/3, so the understeer has been very manageable with driving style changes.

Pyrometer readings showed the camber and toe settings to be spot-on. Tire temps were fairly even across the tire patch on the driver's side, outside tires (Putnam Park has 8 right-handers and 2-left-handers). The right-rear inside patch was little warmer. The right front tire showed the coolest temps, and were event across the contact patch.

HedgeHog

Those would be cold temps...for autox; hence the model A3S03. R3S03 takes longer heat up and thus may not be best for autox. Irrespective of A3's vs R3's, both like 38-42psi as their operating temps while Kumho likes lower temps. (not sure about the newer Ecsta V700)

SleepR1

Hoosier's position on optimum tire grip has more to do with tire temps, than tire pressures. You adjust the air pressures to get you to a temp range of 180 to 200 degrees F. Generally those hot pressures are 38 to 40 for a road racing application using R3S03s. 42 psi would be a bit warm, but if that's what your car takes to get 180 F, then...so be it.

I do know of autocrossers that prefer Hoosier R3S03s for usable life. Although A3S03s are phenomenal dry slalom-racing tires, they don't last an entire slalom-racing season.

FWIW, my Hoosier tire rep, has me use hand-grooved A3S03s as rain tires, BECAUSE of the quick warm-up times of the rubber compound used in A3S03s. A3S03s would overheat in a dry track high-speed application which makes them ideal for low-speed slalom racing (autocrossing).

turborotarypower

AAROTARY was asking about a street setup for tire inflation. all the info i gave him was based on that. since he is running 19" wheels he has the problem of reduced load with the tire which means he has to increase tire pressure to meet load requirements. since his front tires have a lower load rating they will need more pressure to handle the same load as the rear. now the abnormal wear issue was about the wear effects of improper inflation, you are correct about inner or outter tire wear possibly being and alignment problem that's why it's always good to get your alignment ck if your tires show either problem. now when it comes to racing or autox you are going to do the opposite for the best results.

SleepR1

I believe the load capacity indexes are based on manuracturer recommended maximum tire pressures. Adding more air into a tire won't increase its' load carrying capacity index, since the max air pressure was used to determine the number.

turborotarypower

your are correct on the explaination,but AAROTARY'S tires achieve max load at 50psi he originally had all four tires set to 32psi.the load rating is comparable to the factory tires ,but is achieved at higher inflation !

SleepR1

Ahh, that will be a harsh riding FD! I thought AA's car was strictly a show queen. You mean AA actually DRIVES his car to the shows? Dude, get that car on a trailer!