Take off GT500 wheels on my gt what tire pressure?

[srt2stang725]

I know GT500 coupes are supposed to run 35 psi, and my gt is supposed to be 32, with the difference in weight between the two cars what should i be running as far as psi? Any suggestions? Anyone with the same setup? Any help would be greatly appreciated. Thanks!

 

[tmcolegr]

are you running GT 500 wheels or wheels & tires

 

[srt2stang725]

GT500 Wheels and tires

 

[tmcolegr]

I am running 35 psi in my GT 500 wheels & tires

 

[Charlie Sheen]

...the difference in weight between the two cars...

Insignificant - you don't change the pressure when you're hauling 3 passengers. I would put them at whatever it states on the sidewalls.

 

[5.0Shocker]

Yeah, the TP on the door Jam.

 

[lito]

Insignificant - you don't change the pressure when you're hauling 3 passengers. I would put them at whatever it states on the sidewalls.

That is one of the dumbest statements I've read here.

Tire pressure is determined by tire construction, size, use but specially by WEIGHT.

Manufacturers recommend a tire pressure that they estimate will cover all the uses and capacities of a car so you don't have to change your tire pressure when you carry more weight.

Other manufacturers specify tire pressures depending on estimated weight.

The GT500 weights about 100-150lbs more on the front, the rear is quite similar.

The sidewall of the tire usually express the highest pressure it will hold, if you want to go around bouncing at 40+ psi, be my guest.

I would use the same tire pressure that the stock GT does and if you are like me that I'm usually the only passenger and no baggage in the car you could lower your rear tires pressure a bit and make your ride more comfortable.

If you want to go the extra mile and have an infrared temp sensor reader at hand check external center and internal tire temps after a typical ride and if they are somehow close, you are good. If the center is hotter lower your pressure, if it is colder up it. Take into consideration that tires always loose some pressure with time and that sometimes we offer friends a ride. So if you find you optimal pressure, add a couple of psi to cover.

 

[MrClean]

Insignificant - you don't change the pressure when you're hauling 3 passengers. I would put them at whatever it states on the sidewalls.

Yeah, the TP on the door Jam.

Y'all are stating the opposite. I have the same setup, and what I've found over 13000 miles is that the 35 psi leads to the center section of the tire wearing faster than the outside sections; a clear indication of overinflation, so I've backed it off to 33 psi.

This set is almost done (bought them as used take-offs with the rims), but when I buy new ones (my Ford stealership will sell/install them with Nitrogen fill for $187 each), I'm going with the 285/40/18s all around so I can rotate them. The front and rear wheels are the same width.

 

[Charlie Sheen]

That is one of the dumbest statements I've read here...

I stand behind that statement. Perhaps it is your inability to comprehend what I said that annoys you. The manufactures do not recommend xx amount of tire pressure for a sole occupant and then xx amount for a fully loaded car.

Don't believe me? Check your tire pressure with the car empty. Then check it with 4 adults sitting inside. The difference (if you can even measure it) will be insignificant.

 

[W1ldcat]

I put in 32 in mine when the tires are cold and nobody inside. Usualy just me anyhoo.

 

[19COBRA93]

I was getting center wear on mine as well with the 35. I backed down to 32 and it should be fine now. However, right after that I switched to the 20" Shelby Razors so really all I can say from experience is the 35 psi is too much for a GT with GT500 wheels/tires.

 

[lito]

I stand behind that statement. Perhaps it is your inability to comprehend what I said that annoys you. The manufactures do not recommend xx amount of tire pressure for a sole occupant and then xx amount for a fully loaded car.

Don't believe me? Check your tire pressure with the car empty. Then check it with 4 adults sitting inside. The difference (if you can even measure it) will be insignificant.

Now that is even dumber than the first one, psi almost won't vary by weight but contact patch and temperature does. You can check a tire out of the car and check it back mounted and loaded and the pressure change is minimal because of the construction of the tire, but the contact patch and its operating temp will proportionally. Go back to your physics class.

By your theory it will be same to inflate a tire to 25psi or 45psi.

Because Ford does not do it, it does not mean it doesn't happen, BMW does it for example. They even go the stretch to add a sticker where they graphically express the rear tire pressure recommended depending how many people and/or bags are on the car.

 

[tmcolegr]

I have the same setup, and what I've found over 13000 miles is that the 35 psi leads to the center section of the tire wearing faster than the outside sections; a clear indication of overinflation, so I've backed it off to 33 psi.

I was getting center wear on mine as well with the 35. I backed down to 32 and it should be fine now.

Interesting......
Are both of you running the OEM Goodyear tires? I should qualify my original post by stating that I'm running BFG KDWs in the same size as the OEM GT 500 tires - not Goodyears. Nonetheless I'm running 35 psi with no abnormal wear issues.

 

[MrClean]

Interesting......
Are both of you running the OEM Goodyear tires? I should qualify my original post by stating that I'm running BFG KDWs in the same size as the OEM GT 500 tires - not Goodyears. Nonetheless I'm running 35 psi with no abnormal wear issues.

Yes, I'm running the OEM Goodyear Eagle F1 Supercar 285/40/18s in back, and 255/45/18s in front.

 

[Charlie Sheen]

Now that is even dumber than the first one, psi almost won't vary by weight but contact patch and temperature does. You can check a tire out of the car and check it back mounted and loaded and the pressure change is minimal because of the construction of the tire, but the contact patch and its operating temp will proportionally. Go back to your physics class.

By your theory it will be same to inflate a tire to 25psi or 45psi.

Because Ford does not do it, it does not mean it doesn't happen, BMW does it for example. They even go the stretch to add a sticker where they graphically express the rear tire pressure recommended depending how many people and/or bags are on the car.

Read the original post moron.

 

[lito]

Read the original post moron.

No arguments, just calling names out...that speak volumes of you...great.

 

[Charlie Sheen]

No arguments, just calling names out...that speak volumes of you...great.

That is one of the dumbest statements I've read here. S197 GT verts and coupes have a weight difference. Why do they come with the same rims and tires? Please enlighten us.

 

[lito]

That is one of the dumbest statements I've read here. S197 GT verts and coupes have a weight difference. Why do they come with the same rims and tires? Please enlighten us.

You are digging a bigger hole for yourself but be my guest.

Why would them had to change if the same tire can hold the load of a vert???? What does this has to do with tire sizes????? What may change (or not) is the recommended tire pressure from a coupe to a vert (I have no access to verts because there is none down here) given the weight difference NOT THE TIRE.

You said:

Insignificant - you don't change the pressure when you're hauling 3 passengers. I would put them at whatever it states on the sidewalls.

The weight differences of these two cars is not insignificant. (3920 for the GT500, 3483 for the GT, both coupes), you are talking about more than 400lbs more, that is not insignificant, both cars can hold the same amount of passengers and baggage so its final load is more and it is obvious that the GT500 came with a higher pressure recommendation.

Weight is the most important thing to take into account at the time of considering a tire pressure. When we raced we had a group of caterham super 7s, this is a 1000lb car, it uses standard 15" or 16" rims with typical street tyres that you would see inflated about 26-28 on a normal street car, well, in this tiny thing they only use 14-18psi.

You also said that "I would put them at whatever it states on the sidewall" that is another common mistake, the pressure expressed in the tirewall is usually the MAX pressure at the MAX load specified on the load rating. In some cases they also specify a minimal pressure too. They cannot show the recommended pressure because they don't know how it will be loaded so inflating a tire for what the sidewall say is a huge and common mistake too.

Ford, as many other manufacturers just stamp a single recommended tire pressure for simplicity, as I said you before other manufacturers go the extra length and make a more detailed info with their cars. Do you want proof? here you have a picture after a single search on the web:

There you go, proof me wrong.

BTW, you can make my boxes red all you want but that won't make you right.

 

[19COBRA93]

Interesting......
Are both of you running the OEM Goodyear tires? I should qualify my original post by stating that I'm running BFG KDWs in the same size as the OEM GT 500 tires - not Goodyears. Nonetheless I'm running 35 psi with no abnormal wear issues.

I was running the Goodyears and wheels that come on the GT500.

 

[srt2stang725]

very interesting everyone! Thanks for the input!