06-27-2021, 10:09 PM
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#1
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What PSI For 275/55R20 Tires?
Got new tires put on yesterday and realized I don’t know what pressure to run them at. Went up from the factory size to 275/55R20, which is common. I believe factory spec is 32 PSI but what should these be? Still 32 or something else? I checked all 4 and they’re at 42 right now from the tire shop.
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06-27-2021, 11:04 PM
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#2
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42 is way to high. Keep them at 32. With slightly larger tires, you can run a bit lower.
Just be sure you use a good/accurate tire gauge. The stick kind is junk.
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06-28-2021, 02:30 AM
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#3
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If your new tires are also P-metric SL loads, they should also be 32 psi.
Tire Pressure Calculator
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2019 TRD Off Road w/KDSS in silver. Dobinsons IMS59-50700 & C59-314 front (coil seats lowered 1/2"), IMS59-50705 & C59-505 rear; Dobinsons diff drop; Ironman UCAs; Eimkeith PCK, Ironman adjustable panhard rod, and Treaty Oak KDSS spacers; Toyo Open Country A/T III 255/80R17; C4 Fab skids & Shrockworks sliders; Durobumps front & rear.
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06-28-2021, 07:41 AM
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#4
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Quote:
Originally Posted by Tuco S.
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That calculates out to 27 PSI. Is that really correct?!
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06-28-2021, 08:32 AM
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#5
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10% rise in psi from cold to warmed up.
(random starting number) Cold tire 30psi. Warm ideally would be 33psi. If warm is too high (35 or morel, increase cold psi. Under inflated warms more.
If warm psi is less than 10% then cold psi too high. Tire doesn't warm up enough to develop traction.
This is all dependant upon ambient temperature, load, type of driving, etc. Monitor daily for a week or so and find your average.
I learned to do this road racing motorcycles (track, not public streets).
So for MY tires where I live, I run 30psi in winter (temps down to the 20°`s) and 37psi in summer (up to 120°+).
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06-28-2021, 09:23 AM
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#6
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06-28-2021, 11:06 AM
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#7
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What PSI For 275/55R20 Tires?
Quote:
Originally Posted by Tuco S.
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Based on this, I reduced the PSI to 30 before I drove to work this morning. On the drive in, the truck was pulling to the left and I had a small bit of wobble/shake in the steering wheel. Prior to letting the air out, when at 42 PSI as from the tire shop, no pulling or wobble, just a smooth ride.
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Last edited by Frasher4Runner; 06-28-2021 at 11:49 AM.
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06-28-2021, 12:25 PM
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#8
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Did you change from "P" to "LT"? What was your factory tire?
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2012 Trail Edition |KDSS |BLACK| 265/70R17 C KO2's @ 44psi | 250,000+ miles |>Link To Inside Fishing Rod Holder Mod
2017 LAND CRUISER URJ200 | MGM | 285/60R18 | 62,000 miles
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06-28-2021, 01:17 PM
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#9
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Quote:
Originally Posted by Jivewalker
Did you change from "P" to "LT"? What was your factory tire?
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I’m not sure what it said on the old tire itself but I believe they were still factory tires. The door jamb sticker says P245/60R20. What I have now is 275/55R20, no P or LT.
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06-28-2021, 01:30 PM
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#10
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Quote:
Originally Posted by Frasher4Runner
I’m not sure what it said on the old tire itself but I believe they were still factory tires. The door jamb sticker says P245/60R20. What I have now is 275/55R20, no P or LT.
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I think what he’s getting at is your psi should be based on the load index of the tire, not the size. A P rated tire and an E rated tire of the same size would have different recommended pressures.
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06-28-2021, 01:38 PM
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#11
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Quote:
Originally Posted by meltdown
I think what he’s getting at is your psi should be based on the load index of the tire, not the size. A P rated tire and an E rated tire of the same size would have different recommended pressures.
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That’s fine and dandy but I need to figure out what that pressure is! LOL
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06-28-2021, 01:50 PM
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#12
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Post the manufacturer link to your new tire. The specs will show the load rating. Enter the load rating in the tire pressure calculator, and it will kick out a psi.
__________________
2019 TRD Off Road w/KDSS in silver. Dobinsons IMS59-50700 & C59-314 front (coil seats lowered 1/2"), IMS59-50705 & C59-505 rear; Dobinsons diff drop; Ironman UCAs; Eimkeith PCK, Ironman adjustable panhard rod, and Treaty Oak KDSS spacers; Toyo Open Country A/T III 255/80R17; C4 Fab skids & Shrockworks sliders; Durobumps front & rear.
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06-28-2021, 02:02 PM
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#13
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What everyone is saying is correct. You need to find out if your new tire is "P" or "LT", then you can figure out what pressure you should run based on the weight of your vehicle, or, in this case, the weight rating of your stock "P" tires. You will cross reference that to a similar or greater weight rating to your new tire and that will tell you the pressure. The calculator posted above makes it easy if you know the correct tire info.
For instance, my stock P tires were at 32 psi. I went to an LT in the same exact size and I run them at 44psi.
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2012 Trail Edition |KDSS |BLACK| 265/70R17 C KO2's @ 44psi | 250,000+ miles |>Link To Inside Fishing Rod Holder Mod
2017 LAND CRUISER URJ200 | MGM | 285/60R18 | 62,000 miles
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But like a bomb.
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06-28-2021, 02:03 PM
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#14
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The tire pressure calculator shows 3 different options for that tire size:
Metric 27 psi (SL or XL load)
P Metric 26 psi (SL load)
LT Metric 37 psi (D or E load)
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2019 TRD Off Road w/KDSS in silver. Dobinsons IMS59-50700 & C59-314 front (coil seats lowered 1/2"), IMS59-50705 & C59-505 rear; Dobinsons diff drop; Ironman UCAs; Eimkeith PCK, Ironman adjustable panhard rod, and Treaty Oak KDSS spacers; Toyo Open Country A/T III 255/80R17; C4 Fab skids & Shrockworks sliders; Durobumps front & rear.
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06-28-2021, 02:08 PM
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#15
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Quote:
Originally Posted by Tuco S.
Post the manufacturer link to your new tire. The specs will show the load rating. Enter the load rating in the tire pressure calculator, and it will kick out a psi.
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