What is the correct recommended 21” cold tire pressure?

[jebinc]

I had 2os, and swapped those out for 21s. Given this, I don’t trust the door placard information. Googled and search here and all I can find is “airing down” numbers. Even Tirerack only lists max PSI of 50. Anyone know for fact, what Rivian wants in these to achieve EPA rating under optimal conditions?

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[SANZC02]

I had 2os, and swapped those out for 21s. Given this, I don’t trust the door placard information. Googled and search here and all I can find is “airing down” numbers. Even Tirerack only lists max PSI of 50. Anyone know for fact, what Rivian wants in these to achieve EPA rating under optimal conditions?

A lot of people have pictures of the door stickers on Cars&Bids, here is one for the 21s.

 

[jebinc]

A lot of people have pictures of the door stickers on Cars&Bids, here is one for the 21s.

Many thanks! I’m low at 43, then!

 

[911.1 Guy]

Generally the "max" psi listed on the tire is correct for a truck this heavy.

 

[jebinc]

Generally the "max" psi listed on the tire is correct for a truck this heavy.

So, you fill yours to 50, cold? Once they warm up, you would be exceeding the max rating, no?

 

[goldburger]

Isn’t tire pressure also listed in the owners manual? I’m too lazy to look myself…

 

[goldburger]

So, you fill yours to 50, cold? Once they warm up, you would be exceeding the max rating, no?

I fill to 48 cold.

 

[madgrey]

Generally the "max" psi listed on the tire is correct for a truck this heavy.

That may be true in some cases (coincidentally) but you want to follow the door jamb sticker or the owners manual, which give recommendations for the vehicle using a specific tire size and sometimes even a load scenario. The tire sidewall doesn't know the application.

 

[jakef801]

I leep at 45 psi cold on mine.

 

[R1T Preds Fan]

So, you fill yours to 50, cold? Once they warm up, you would be exceeding the max rating, no?

No the max pressure is also measured at cold not expansion temps/pressure at warm. My door placard states 48psi but I have always run a couple pounds over in all my vehicles for better efficiencies and tire life. I run 50lbs and see anywhere from 51-53lbs at warm temp… The manufacturers leave 8-12% threshold (depending on brand) under the actual limits of all tires… before you could actually reach any full limitations of the tire…
Now that being said if you live in pot hole city or constantly run a vehicle at max GVWR then you want to give yourself more breathing room…

 

[LL75]

Summer is coming up in Texas. Will be low 75 to high 100 plus soon. What is the recommended pressure for this that would give best ride and efficiency? cold 48 psi still for 21"?

 

[922110]

Summer is coming up in Texas. Will be low 75 to high 100 plus soon. What is the recommended pressure for this that would give best ride and efficiency? cold 48 psi still for 21"?

Yes, 48 PSI cold. I'd definitely check them when the temperatures heat up.

Generally higher PSI is better for efficiency while lower PSI is better for comfort. Just set it to 48 PSI and don't worry about it.

 

[beyondgravity]

I had my tires replaced to 21s by Rivian in Mar’24 when it was cold. So when I noticed on a warm day yesterday, it was 54 or 55. Should I drop it down a notch or assume the mobile tech knows what he was doing and just roll with these PSI.

 

[LL75]

I had my tires replaced to 21s by Rivian in Mar’24 when it was cold. So when I noticed on a warm day yesterday, it was 54 or 55. Should I drop it down a notch or assume the mobile tech knows what he was doing and just roll with these PSI.

check in the morning and set it to 48 psi. It should be around 50 to 51 psi warm.

 

[beyondgravity]

ok team! What is the max PSI the 21s can handle when warm. As I said, mine goes to 54 and I get super efficiency. Why shouldn’t I trust the Rivian technician who set the prsssure knew what he was doing? What could be the worst outcome, when summer really heats up in NJ/PA area

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