| furball |
| (Post Master Sr) |
| 12/18/23 08:33 PM |
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Tire PSI when down-sizing/plus-sizing? Winter vs summer?
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In short, wife's XC90 has summer 275/40R21, door jamb says 21" @ 38psi.
For winter running 235/55R19 @ 40 PSI winter tires ... same PSI or?
Is there a general formula/standard on what to set the PSI to? Or stick with the jamb? ???
For myself on the TLX, I run 17" summer and winters, but I typically go +2PSI for winter to account for air temp shrinkage :shrug: Makes for quite a shitty, clunky suspension ride... (Though for some reason, the mushy winters make for a better ride even tho PSI is higher.)
| Screamin Type ARGH! |
| (Post Master Supreme) |
| 12/19/23 08:52 AM |
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Re: Tire PSI when down-sizing/plus-sizing? Winter vs summer?
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overthinking man, just run whatever's in the door jamb regardless of up/down sizing.
in winter i usually add in 1-2psi more all around as you'll lose some in the cold weather, and most ppl have short drive cycles in the GTA so not like you're warming up the tires tons in cold+city driving.
| LNXGUY |
| (Post Master Supreme) |
| 12/19/23 09:08 AM |
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Re: Tire PSI when down-sizing/plus-sizing? Winter vs summer?
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I run my winters at like 31-32 lol.
| 4Three |
| (Post Master Sr) |
| 12/19/23 09:26 AM |
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Re: Tire PSI when down-sizing/plus-sizing? Winter vs summer?
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In my opinion, a couple PSI either way isn't going to make a lot of difference. You'd also have to assume that your pressure gauge is calibrated to that level of accuracy before you could even argue that those couple PSI have a notable (most likely subjective) affect. But that's me, and I'm using peasant equipment.
| furball |
| (Post Master Sr) |
| 12/19/23 09:37 AM |
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Re: Tire PSI when down-sizing/plus-sizing? Winter vs summer?
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My peasant equipment shows in kPa, so it's even more 'accurate' ... sure makes for an eye-twitch when all 4 are different values
Originally Posted By: 4Three
...I'm using peasant equipment.