20" tire PSI - please help me get it right

[Arsenalslr95]

Trying to figure out where to set the PSI on these new wheels. 20" 255/35/20 up front and 275/35/20 in the rear. When I first received them, the dash showed them at 45-47PSI after the sensors were trained and I was cruising on the hwy. The car rode awesome, but from what I know about tires, that was way too high. The sticker in the door jam calls for 32psi cold with the factory 18" 235/50/18 tires, tried that and the car rode kind of weird. I heard the GT with factory 20" wheels calls for 34psi cold, tried that the last few days when it was slightly cooler and after warming up they reached 37 and the car felt great. Today it was at 34 cold and it was just up to 39psi after warming up a little while ago on this much hotter 100 degree Florida day. The car drove hard and the MPG seemed to tank some. Any suggestions what cold temp I should set them for this tricky FL weather thats humid, rainy, and varies from 80-105 degrees every other day?

Thanks

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[Tcstang]

Use an actual tire gauge. The dash always reads high compared to what my actual gauge says. I have the factory 20's set at 36 PSI but the dash reads 39 to 41 PSI.

 

[Arsenalslr95]

Use an actual tire gauge. The dash always reads high compared to what my actual gauge says. I have the factory 20's set at 36 PSI but the dash reads 39 to 41 PSI.

Yea I have heard many people saying they have variances in dash reading and actual. My dash seems to be on point. Whatever my hand held gauge says is exactly what the dash says, and the same for the newer air pumps at gas stations where you preset the PSI you want and it only pumps to that. Is yours 36 cold or after driving awhile?

 

[r-model]

Check the sidewall of the tires, they will tell you what they should be cold, this is usually given as a maximum pressure.

 

[bigspoondude]

Check the sidewall of the tires, they will tell you what they should be cold, this is usually given as a maximum pressure.

Under no circumstances should you inflate your tires to the maximum sidewall pressure. This will cause extremely excessive wear on the middle of the tire and they will be shot in half the time that they would normally last. I would go with 36, and check how the tires are wearing after a month.

 

[GoBlues38]

I run mine 34 cold > 37 hot.

Seems to be the best wear pattern. too little, you wear out the shoulders. Too much, you wear out the centers.

 

[GoBlues38]

Check the sidewall of the tires, they will tell you what they should be cold, this is usually given as a maximum pressure.

WRONG

tire side wall is just for item specific to the tire, does not take into account manufaturuer suspention settings. the tires can handle a broad range of cars.

The door jam is always the best place to start.

 

[Tcstang]

Yea I have heard many people saying they have variances in dash reading and actual. My dash seems to be on point. Whatever my hand held gauge says is exactly what the dash says, and the same for the newer air pumps at gas stations where you preset the PSI you want and it only pumps to that. Is yours 36 cold or after driving awhile?

Mine is 36 cold.

 

[MELLOWYELLOW06]

35 to 37 before you get to running temp

As you drive and temp climbs, the pressure naturally expands 2 to 3 lbs.

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