Time for some thinking here

[Ponycarman]

I have an interesting puzzle, I have my opinion on this but I thought I'd run it past everyone to see what shook out.

I bought new tires yesterday. For reasons not germane to the question I stayed with 15" rims. However, I did upgrade the width.

The question, what should my tire pressure be?

The specs:

Original tires:

205/65-15
35 psi max tire pressure
1400lbs carrying capacity @ 35 psi.

New tires:

225/60-15
44 psi max tire pressure
1592lbs carrying capacity @ 44 psi.

Sticker says:

35 psi for the 205 tires

So the question is what psi should I run? Too much and the center tread wears out fast. Too little and the out edges wear out too fast and the car is wiggly. More pressure usually means less rolling resistance, which equates to better performance and mileage.

Steve

[232stang01]

I would think 35 psi should be fine. The only reason I'd change that is if I was going to the track. then I'd got 40 in the front, 30 in the rear.

maybe go 40 all the way around.

Anyone else got any ideas?

[WhiteStang99]

i think my 44 max PSI tires are right at 38 all the way around.

[Fishers Stang]

35 all the way, heck i dont know... hahaha but in the vic its 35, my stang was 32 with the stock rims, now it reads 35

[SpectorV]

the max number is not what you want to run, not sure on yours but on my 275 17's i run 32psi and they wear great.

[Ponycarman]

Well, I know four ways to find the right answer.

One is to put some rubber down and inspect the marks. If the tread is even across the track then the pressure is good, light in the center, add more air, light at the edges, lets some air out.

Second it to put many miles on them and see how they wear. Not quick and not cheap if you wear out the tires by having them under/over inflated.

Third is to ask around.

Finally, do some math.

1400lbs @ 35 psi works out to 40lbs per psi

1592lbs @ 44 psi works out to 36lbs per psi.

38 psi in my new tires works out to 1400lbs capacity in my new tires. This would be my starting point.

Steve

[SpectorV]

or inspect the tire wear and add air as needed.

[Ponycarman]

Yeah, but that method is long term. With 35 psi in the tires right now they feel too loose. So I'll go with 38 and monitor them.

[SpectorV]

having more area around the rim i would just about bet they need more.[quote]

[ttpancakes]

Quote: Originally Posted by 232stang01 I would think 35 psi should be fine. The only reason I'd change that is if I was going to the track. then I'd got 40 in the front, 30 in the rear. maybe go 40 all the way around. Anyone else got any ideas?

[red herring]

i would just do what you like for traction, if they wear funny rotate them around a bit

[SpectorV]

i rotate my tires every 3k its only like 15 min of work and it really makes em last longer.