Over Inflated Tires
 

I'm curious. I recently put 42 pounds of air in my trucks tires. They are rated for 35 psi max. How high could I safely go? P205 75R 15
Also, the truck came with P235 70R 15, would I see better mileage with taller tires?

thats about as high as i would push um. waht kinda truck do you have? it might help for outer peoples awnswers

Alas: Any time you go over the sidewall pressure rating, your a little on your own.

Their are some members who won't run over the sidewall rating because they don't want to take any unnecessary chances. Their are other members who run over, but on the whole I don't think anyone recommends that someone else run over.

That said, I've been running 55psi in 13 inch tires on a Honda Civic, which are rated at 35. I have not encountered any issue in the last 9 month's that has caused me to seriously feel that they have been unduly safe. I know the car coasts a good deal further and I haven't been inclined to reduce the pressure, yet.

I have run 55psi before, in tires rated at 35psi, in the summer, across the desert in 110 degree heat, without having any issues I could discern. In doing so, I never had a blowout or any flat tires I could associate with the elevated tire pressure. I do feel the tires ran substantially cooler than they had previously when I ran them at the rated pressure. I also had several instances of having blowouts, when I did run them at lower pressures, in that high a temperatures.

It's really up to you, what your willing to try or what your comfortable with trying.

On the tires, do you have any idea of what rpm your running at highway speed's. You might see better highway mileage with a taller tire, but I wouldn't change them unless you need to, anyway. Your mileage might be better, but I doubt it will be enough to pay for new tires, before their time.

I'm running 55psi on 225/70/15's rated for 35psi. I drive a 93 Jeep Cherokee 4x4. I like the feel so far.

You could be a rebel like Hunter S. Thompson and run your tires at 80psi (I think they were rated for 40).

Tire blabber :D
 

P205 75 R15 is the tallest and narrowest together you can get together in a 15 inch rim. They are pretty light too. Notice, though, your tire selection, is pretty much only all terrain and only 35 psi rating.

That is the standard tire size for my caprice is 205/75, too. I had the tire size upgrade option on my caprice, 225/70, but I didn't like the tires to select from. Also, both of those tire sizes only come in 35 PSI rated tires.

I found out there is a different tire selection for P215/65 R15 and about half of those have 45 PSI TP ratings. I got "Kumho Solus KH16" because of the good reviews, and low price. They are the same diameter as the 205/75's. Though they are as wide as 225/70's, I can run higher PSI in these :)

Plus the "Kumho Solus KH16" 215/65 tires I have are AA traction rated, they are excellent at sweeping away water, and they stopped the boat-like handling my car used to have.

Sorry for the long post, and the tire review:rolleyes: Tire opinion varies widely with who you ask. You could try the "Sumitomo HTR H4" LRR tire and 51 rated PSI!

I see you have a 4X4... Some truck tires I want to experiment with on my Blazer are "Pirelli Scorpion ATR" they are heavy and aggressive, and twice as expensive. But they have super reviews. I want these because of the weight rating and TP rating.:eek:

I dunno what the equivalent is, but tires with some max cold pressure can handle that on the hottest day with the roughest roads and the highest speeds, and that likely translates to a higher cold pressure assuming you aren't pushing all the other extremes.

It is a good idea to check to see if your car manufacturer has any suggestions for what the car can handle for more "extreme" driving.

Case in point, Mercedes has these suggested inflations (cold psi) for my 190e:


(Front / Rear)
Normal Load: (27 / 29)
Max Load: (29 / 34)

Warm Tires: + 4 psi

100 mph+ Driving: + 7 psi


I am currently running the tires (Michelin MXV's) at 40 psi (cold) and the sidewalls have a max rating of 44 psi. The car does steer more easily, but the tires do squeal more in hard turns.;)

personally i wouldn't even run as high as you are now. if i ever forget to lower my tire pressures after an autocross or something, the car always feels way too squirrly at highway speeds. there might be a middle ground there but at 42+lbls, i'll take the safety over the 1-2 mpg.

not to mention heavily accelerated inner tire wear ;)