What is a good tire pressure?

[jpumpkinn]

I drive my stang every day and have always thought that 35 psi is a good tire pressure to drive on. My tire max psi is 44psi. Is running a lower psi bad for my tires? What will make them last longer? Also, they do not hook up at all, I spin them all the time. I have potenza's, I thought these were good street tires? Why do they not grab?

Any opinions?

[Tony Frank]

If you over inflate your tires they will wear in the center of the tire, if you run them underinflated the outsides will wear......

you might be too low on pressure if they arent hooking up.

lower pressure will only make slicks hook better and not street tires. i could not tell you what pressure to run im not sure exactally.

[gtsr515]

Mr. Pumpkin, this is a super question! one that needs to be assured to all our readers and i feel i am more than qualified to answer correctly.

I presently work for SKIP BARBER RACING SCHOOL here in Sebring, Florida as a road racing instructor.

As far as proper pressure for your street tire, the MAXIMUM PSI stated on the sidewall is 95% of the time the correct pressure to run, what is it that makes you think 35psi is generically correct?

In some cases, usually when running your car on a autocross, or true race track, maximum pressure is actually increased a little to help the side walls from rolling over during hard cornering and to improve overall braking performance and most importantly "contact patch", BUT, only if the tires in question are in perfect condition and capable of handling the performance your asking from them in the first place, such as yours. REMEMBER, your tires are the only thing in contact with the road period, so, pressure is key to optimum performance. i feel i have started you on the right path, if you would like to hear "advanced tire tech 101" reply further!

Wouldn't YOU like to have a GTS Viper as an office? I am so lucky, and will share ANYTHING I learn day in and day out. As a matter of fact i heard Helio Castro Neves of Champ car racing today say this about being in a spin today at work (I personnally instructed Al Pacino last week, LOL! God! does he suck at driving, good thing he can act! LOL!), here it is. This relates to a manual transmission car only.

IF IN DOUBT, BOTH FEET OUT, IF IN A SPIN, BOTH FEET IN.

Also he says, when over 90mph, purposely concentrate 1 mile ahead, visually impossible, but, CONCENTRATE a mile ahead, this will help you in braking.

[jpumpkinn]

Wow! Gtsr515 you have a very cool job! If I had the cash I would be a viper fanatic. I hope to buy one some day. Thank God there is a lower price toy that I can play with. I guess my theory for under inflating tires came from my father and from the idea that slicks work well under inflated. I am glad I asked. I will inflate my tires back to max psi.

I have always wanted to go to a driving school, maybe some day. How did you get into this proffession? Does the school have a website?

As for AL good thing he can afford a limo and driver!

[Mach 1]

Thats strange. I never heard the theory that the MAX pressure is the CORRECT pressure 95% of the time.

MAXIMUM and RECOMMENDED dont mean the same thing do they?

I was always under the assumption you should follow the manufactures recommendations that are on the sticker on your door jamb, this is assuming you are running the same size tires and wheels that are on the stickers or came on the car originally.

When I worked at a garage, we always inflated tires to 32 PSI as that is where the tire machine was set as the recommended pressure, and also what seemed to work well on most applications.
Im interested in how "maximum" is the same as "preferred or recommended or proper".

Can you please elaborate?

[OUTPLAYN]

Ok..I just have to put my 2 cents in...When it comes to dragracing...reg radials should go up in psi more in the front for less resistance...I know when I went up in psi in the rear..car hooked up better...and got better ET's..lower psi's has made me spin more off the line.

[gtsr515]

WOOOOOOOOO! I must have misunderstood the question, I didn't realize we were talking SLICKS!, OOPS!

Oh yea, slicks can work great underinflated, but i use that word as a reference, actually slicks work best when PROPERLY inflated, and here's how to do that.

Next time at the track, inflate them to well above a psi you know is high, make a pass, keep lowering your pressure until you blow them away, launching at the same rpm each time, track conditions will play, but that is beyond your control, weather as well as the day heats up.

Check out www.autotrader.com for sub $30K Vipers, little damage, easy repair.

The 488 is an amazing motor, i wish you all could feel it.

[jpumpkinn]

So what is the verdict?

Is the max psi better or is it better to go lower on STREET RADIALS? The manufacturers recommendations don't apply to me because I am not using the stock tire size.

[gtsr515]

The verdict with street radials proven tire after tire with our school tire changers, god bless their souls, is maximum inflation per tire run, or like i said earlier a little more, and i mean a LITTLE more.

Even more so in a drag racing launch situation. Contact patch=traction PERIOD!, sorry i forgot that part, notice above outplayn said his times were better when he INCREASED his pressure, more contact patch my friends!, and overinflating the front will decrease rolling resistance as well, BUT PLEASE ONLY DO THIS IF YOUR TIRES ARE IN TOP CONDITION, SAFETY FIRST!

[Mr 5 0]

I keep my Firestone Firehawk SV50's at 38 - 40 psi. Different types and brands of tires will require slightly different pressures but 35 - 40 is about average.

Maximum psi won't hurt you assuming the tire is in good condition and mounted properly. One of the most common sources of both tire wear as well as tire failure (blowouts) is under-inflation.

You know the rule; always check tire pressure on a cold tire and check them once per week, minimum. Above all, don't run under-inflated tires. Both you - and your tires - will last longer.

[gtsr515]

Here's what I set my Goodyear F1's:

With girlfriend - 35psi
Without - 42psi

LOL