Why Even Tire Pressure Matters More Than You Think

[electruck4x4]

After a rotation, tire pressure balance becomes critical.

What we often see:

• One tire 3-4 PSI off from the others
• Shops setting pressures inconsistently
• Owners not realizing how uneven pressure accelerates wear

On a heavy EV, uneven pressure compounds faster.

It’s one of those details that seems small… until it isn’t.

Are you checking manually, or trusting the shop to get it right?

— Team Electruck

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[KBabione]

I cycle through what the Rivian reports as the tire pressures about once a week. On our R1S the Rivian TPM is about 1 psi above my handheld gauge, but as you suggest, I'm confirming that they're all within 1 psi of each other.

 

[kewlasu]

I just had my tires rotated. The local shop aired them to the same pressure before installing them. Rivian TPMS all reported them the same pressure after I drove off and still showing them evenly the same after a few days.

 

[UnsungZero_OldTimeAdMan]

The "shop" be it independent or Rivian SC, generally are good on pressure—verified by a glance of driver display and what the TPMS is reporting. However, pressures of all 4 aren't always exactly the same due to driving and environmental conditions. Unless they are vastly different, more the a few psi's apart, I don't worry too much about it. When they are different enough, I have a modified Speedflate 4-tire inflation/deflation kit that makes equalizing easy. And I do this maybe once or twice a year.

 

[SANZC02]

I agree, environment can make a big difference. If my R1S sits in the driveway, the sunny side of the vehicle can be as much as 3 PSI higher than the shady side.

I rotate my own tires so I’m to blame if they are not correct. I usually check the pressure first while the vehicle is still in the garage and fill accordingly before I drive out to rotate them.

 

[ndmiller]

I'm still old school checking tire pressures on all four of our vehicles with a compressor in the garage. Use this and a high end inline gauge I can remove and use along during cold to hot tire periods (only letting air out).

Even with my 2-4 week checks pressures go from even to uneven and I then even them out. The reason is tire replacement is $1-2 per vehicle so extra tire life I get from checking and regular 5K intervals are meaningful to the bottom line. If it didn't matter from a $ figure I'd never do it but the first time I was an adult buying tires, I started checking pressures regularly. FWIW I also check the oil every time we fill up our ICE vehicles with gas.

 

[AFineOldWine]

Which Rivian provided tire pressure reading do you trust?

UPDATE: after an unrelated SC visit, they reset tire pressure to match TPMS, so I'm assuming the compressor is reading high.

I have a G2 R1S with compressor. The TPMS values read about 3 PSI higher than the compressor fills to. Given the lag in TPMS update, it's not easy to sort out.

Yeah, I _could_ get a manual tire gauge, but then I'd have 3 different values and something to rattle around somewhere.

 

[SwampNut]

It funny that you create these silly engagement posts without even knowing that Rivians have tire pressure monitors and you can glance at it easily. Rivian SC always sets my pressure too high, so I correct it after every visit.

 

[UnsungZero_OldTimeAdMan]

Which Rivian provided tire pressure reading do you trust?

I have a G2 R1S with compressor. The TPMS values read about 3 PSI higher than the compressor fills to. Given the lag in TPMS update, it's not easy to sort out.

Yeah, I _could_ get a manual tire gauge, but then I'd have 3 different values and something to rattle around somewhere.

None of these things use lab-grade accurate sensors. And unless you are managing a Formula 1 car, your tire pressures don't need to be pin-point accurate.

There are also factors you're ignoring. A warm/hot pressure gauge on the compressor could read high because of it. You can trust them, or distrust them all, just the same. The key is consistency—i.e. use the same gauge and stick to it. Even if it's not pin-point accurate, your deviation is at least consistent. Mixing results from different measuring devices—and drawing conclusions from that mix bag of data—is just scientifically unsound.

Environmental factors is another thing. Parked and cold (not after driving), one side of the car that is in the sun can easily read 3 psi higher than the side that is in the shade. Even with a gauge that is not terribly accurate.

 

[SwampNut]

My compressor and TPMS are always in agreement within less than 1 PSI, mostly dead on. My other gauges disagree by 2. I roll on 45 PSI per the Rivian, and the chalk test shows that's right on.

 

[SwampNut]

And unless you are managing a Formula 1 car, your tire pressures don't need to be pin-point accurate.

It's not an F1 car, but I do live here...

 

[LL75]

does it matters that much within 5 psi? In texas, morning cold reading and mid day is about 5 psi diff. due to 20 to 30 degree temp changed

 

[AFineOldWine]

the chalk test shows that's right on.

TIL! Thanks (how to do a chalk test)

 

[SwampNut]

TIL! Thanks (how to do a chalk test)

Thanks, I realized I should have said more. This tells you a lot, since "recommended" tire pressure accounts for heavy load and worst case.

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