[Blaseleblanc]

Finally put on my new wheels. They are 19" AMR's with Sumitomo HTRZ III 245/45/19 Tires. Can anyone tell me what tire pressures I should probably be running on these? The max PSI is 51. I currently have them at 48, and I'd like some opinions since I can't find a recommendation anywhere... AM balanced them at 44, is that what I should stick to?

Thanks! :bigthumbsup

 

[2013 GT 5.0]

That seems kind of high. My new GT came with the Pirelli P Zero Nero tires in the same size that you have. I go by the sticker on the door jamb. It states that the cold tire pressure for my vehicle is 32 PSI. My wife's Honda Odyssey Minivan has a cold tire pressure of 36 PSI.

 

[white rider]

my 255/40/19 pirellis (the summer performance one from the performance package) are supposed to be 35psi i think. 48 seems really high

 

[diver88]

I agree, the sticker inside the door say's 32psi... I feel every pebble, crack and grain of sand, I couldn't imagine how the car would feel over 40psi. kinda unscientific but after I drive any vehicle I notice the contact with the ground usually makes a visible line around the outside edge of the tire and about a quarter/eighth inch off the shoulder is about consistent with door jamb recommendations in my experience.

:bigthumbsup

 

[Grim2013]

That's weird. My door jamb insert says 35 psi. Why do some Mustangs have a different recommended cold pressure of 32 psi?

 

[2013 GT 5.0]

Also I've always been told that you go by the recommended tire pressure on the door jamb. Not the sidewall of the tire. I also believe the above is stated in the owners manual.

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[Blaseleblanc]

The door sticker says 35 psi for my stock 215/65/17 tires... It seems counter intuitive that the same pressure would apply to non stock size rims and tires, does it not?

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[diver88]

The door sticker says 35 psi for my stock 215/65/17 tires... It seems counter intuitive that the same pressure would apply to non stock size rims and tires, does it not?

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you ask a good question, I don't know. I have always been under the impression that pressure is pressure and the suggestion inside the door jamb is what is appropriate for the suspension and the geometry of the car however with 17" tires, wheels, steering gear, and any other differences 35psi must be right for that set up, and with 18"wheels and maybe a different steering gear and whatever else might be not the same 32lbs is right for my car. sidewall height on the OEM tire is my guess as the pressure difference between your car and mine. so I'd start with 32psi if it were me...but

like I said before, I'd see where the contact patch is riding by looking for that line near the outside of the tire tread and get it within an 1/8th to 1/4" from the edge... that way you shouldn't be over or under inflated. that wheel/tire combo might need more pressure to sit properly on the contact patch.

 

[Strat4477]

I heard somewhere that the manuals (at least v6s) have a higher stated psi rate to try to bring up the mpg.

The door sticker says 35 psi for my stock 215/65/17 tires... It seems counter intuitive that the same pressure would apply to non stock size rims and tires, does it not?

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[Ltngdrvr]

You should always stick to the pressure listed by Ford for the applicable tires size, so if you have changed tire size on your car then you will have to figure it out.

Now, some Mustangs came with the 245/45/19 tires(GT/SC and regular GT's with optional 19 premium wheels) so find out what Ford recommends for those cars and use that.

Also, the 215/65-17's on V6 automatic cars are setup for 35 psi because those are the gas saver tires.

NEVER run the tires at the max psi setting listed on the sidewall. Running the tire pressure that high, or even appreciably higher than the standard setting will cause the mentioned rough ride and will also cause the center ribs of the tread to wear faster than the outer edges.

Running a slightly higher air pressure can help with fuel economy but like I said, it can also make the tires wear incorrectly.

 

[Blaseleblanc]

Found the door sticker, for anyone else who needed the info. I'm surprised the recommended pressure is so low in fact, but hey...

 

[Ltngdrvr]

Found the door sticker, for anyone else who needed the info. I'm surprised the recommended pressure is so low in fact, but hey...

Yep, that's standard deal, 32 isn't that low, they've never recommended anything higher than 35 psi. The slightly lower pressure helps smooth the bumps with the low profile tires.

 

[2013 GT 5.0]

32 psi is not that low. I can't imagine what 48 psi would feel like.

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[RodgerJerney]

My dealership said 35 psi. <They're car guys. 3 of them have a Mustang. Good enough for me.

 

[Tominator]

The short of it is that the tire maximum load rating is for the max PSI on the sidewall. Of course you likely will never even get close to that so it makes no sense to increase the PSI.

As you guys determined, use the door sticker:yup: