What air pressure for new tires
- Thread starter nickaluch
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What's on the sticker that's on the driver's side door pillar, or door? There should be a tire pressure reading there.
The door sticker calls for 30 pounds but a different size tire is now installed
^^^^This.^^^^
My truck calls for a 235/70/17 or a 265/65/17. I have 245/70/17 on it. The door decal reads 38 psi. I run 35 psi. With 38 psi I can run over a penny and tell you if it's heads or tails.
the same
Load index is key to answering the question.
Not sure if this chart is up-to-date, but this may be a good starting point:
The obvious question is why not install the original tire size? Have you compared the circumference of the 2 sizes?
When I've installed a different size I've gone wider, not narrower.
When I've installed a different size I've gone wider, not narrower.
The door sticker ONLY applies to the exact OEM tires. If you change brand or size of tires, the door sticker is a guideline and no longer applies.
Read that again if confused.
I’d run 33 PSI for a week or two and see how they handle. Check for unusual wear patterns after a few months.
Read that again if confused.
I’d run 33 PSI for a week or two and see how they handle. Check for unusual wear patterns after a few months.
Nick1994
$100 site donor 2024
I like 2-3 over sticker to give room between tire fill ups. Unless the tires wear in the center, I had that on my Genesis' rear tires.
I think the proper way to do this is to use the load tables to first look up how much load is supported on your OEM tires at the door jam pressure, and then look up what pressure will support the same load on the new tires.
In practice it won't change much because you're likely not changing the tire size that much. For example, my door jam says 32 PSI on stock 225/55R17 97H tires, and when I did the load table calculations on my 215/65R16 102T XL winter tires the equivalent pressure ended up being 31 PSI...so no significant change.
The moral of the story is you don't have to worry about it and can just continue using the door jam pressure as your guide...that's what everyone just does.
In practice it won't change much because you're likely not changing the tire size that much. For example, my door jam says 32 PSI on stock 225/55R17 97H tires, and when I did the load table calculations on my 215/65R16 102T XL winter tires the equivalent pressure ended up being 31 PSI...so no significant change.
The moral of the story is you don't have to worry about it and can just continue using the door jam pressure as your guide...that's what everyone just does.
What does it say on the sidewall of the new tire itself? All tires are marked as to inflation pressure. I like to run about 5 PSI under max. I like a firm ride, and don't have to worry about rain and snow. If you do run a bit less.
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This guy gets it. Spot on.
So what if there are 3 different brands of tires installed from the factory?
If anything, you would deviate from the placard based on the tire's load rating, not the size, and especially not the brand.
He doesn't and it's not.
Under normal operation you should be nowhere near the max inflation pressure on the sidewall.
Ah ....... Mmmmmm ...... Not exactly.
Ya' see, tires are standardized. So it doesn't matter WHO makes the tire, if the size is the same, the load carrying capacity is the same at the specified pressure.
I go into more detail here: Barry's Tire Tech: Load Tables
Yes, different make/models of tires may FEEL different, but that's because of the way the tire manufacturer wanted it to feel. The load carrying capacity (and this is a safety issue) is not.
Been running that way for over 50 years, on both bias ply and radial tires. In weather from -20F to over 120F, and never had a blowout or a problem. And have gotten good tire and fuel mileage from doing so.
Far more tires suffer from under inflation than over inflation. And it's one of the main causes for premature tire wear and blowouts.
A P225/50R17 has a load carrying capacity of 1433# @ 35 psi. A 215/55R17 has a load carrying capacity of 1433# @ 35 psi.
Use the same pressure.
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