Tire psi

[Mr Now]

Bought my 2024 mustang ecoboost last week and all four tires were at 42 psi. I lowered them today to 35 psi. Do you have any recommendations?

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[Sofa King]

Go by the placard in the door jamb... probably 32 psi.

 

[JAM486HP]

My GT with NP wheel/tires came over inflated to 42, I run them at 32 psi cold.

 

[ShaZadam698]

My GT with NPP/PP came at 40, i have lowered to 32

 

[Zig]

the app shows the recommended pressure.

service -> vehicle health

 

[Crew4991]

32psi all around for the most comfortable ride as recommended by the manufacturer.


Don't be like this person:

 

[Mr Now]

100 it is!!! I’ll drop to 32

 

[DontHitMeSafetyYellow]

Also, keep in mind that time of day and sun exposure can drastically change the PSI during the summer in particular.

For example, this morning I got in my car (parked outside but shaded) and all showed 32psi. When I go out to my car at lunch time, sitting with the left side tires in direct sunshine on an 80F day, the lefts will be at like 36 and the rights at 34.

Consider the “cold” conditions when setting your pressures.

 

[RLE55]

Also, keep in mind that time of day and sun exposure can drastically change the PSI during the summer in particular.

For example, this morning I got in my car (parked outside but shaded) and all showed 32psi. When I go out to my car at lunch time, sitting with the left side tires in direct sunshine on an 80F day, the lefts will be at like 36 and the rights at 34.

Consider the “cold” conditions when setting your pressures.

Correctamundo. As mentioned in another thread, for every 10* change in ambient temp, psi will go up or down 1 psi. Also keep in mind as you drive the car, tire friction will increase psi, but that's expected and nothing to fret over.

 

[Mr Now]

Truth! I’m in Phoenix and when I lowered the pressure to 35 psi, it was 102° F at that time. . In the morning, it was 70° F and the tires read 32

 

[RLE55]

Truth! I’m in Phoenix and when I lowered the pressure to 35 psi, it was 102° F at that time. . In the morning, it was 70° F and the tires read 32

AZ is the unicorn for tire psi.

 

[Skye]

Starting at 42 psi / 2.89 bar, it would seem the dealer did not lower them to the recommended level from when the car was shipped. Good of you to check, and something for everyone to check, especially if traveling after signing.

The placard in the door jam would be your starting reference. Mine is 33 psi / 2.27 bar. I'm using aftermarket rims and tires which are within 3% of factory. Setting the pressure to 33 psi cold continues to be the sweet spot, in both appearance of contact patch (see dirt) and physical wear.

By "cold" I measure in the AM, when coolest, in a covered garage. I always check the same way in the same place.

The Ford TPMS sensors as nice for a quick read in the display, but they round up. They are not very discreet. For example, 32.5 will register at 33. One-half psi, .03 bar might not seem like much, but, given the volume of the tire, it can make a difference.

Previously, I'd used a common, pen-style gauge. With the car, I upscaled to something better: the Autometer 2160.

https://www.autometer.com/performance-analog-tire-pressure-gauge.html

Using the Autometer, I confirmed how the TPMS system rounds. I also confirmed the pen-style gauge was inaccurate by as much as 2 psi / .13 bar.

Pressures are checked once a week. That seems a bit much, but if you're going to be doing any spirited driving, it gives you confidence things are set as expected.

About three times a year, I confirm and record tread wear with a tread depth gauge, a Milton, metal unit:

https://miltonindustries.com/products/tire-tread-depth-gauge

Especially early on, I wanted to know the factory alignment was OK. It was. And with the tires, I wanted to confirm they were not under or over-inflated. Another advantage: you get down and physically inspect the tires. If something is off, you should notice before things get too bad.

At the moment, I have a bit more wear on the edges than the core, something I expect with an independent suspension.

Finally, with a square setup, I also rotate the tires once a year.

 

[24BlueStang]

The sticker on the door jam is 32 psi COLD. They will gain psi as you drive but don’t worry about that. As long as they’re at 32 when cold you’re good.

 

[GoofyNoober]

Would you recommend I put air at a gas station or at a tire shop?

 

[RLE55]

Would you recommend I put air at a gas station or at a tire shop?

Air is air, unless you want nitrogen mix, which isn't really beneficial except for race tires. Most gas stations have the air stations that cost, whereas tire shops are mostly free.

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