A tire pressure question...

The tire pressure door sticker shows the value for
305/50/20 tires
30 front 33lbs rear.
I bought it with 90% new Cooper SUV /truck tires can't think of the model ATM.
Here's the pickle....the tires on the truck are 275/75*/20
Does the psi value remain the same* or does it need be changed to accommodate the smaller tires ??
If so where do I find said specs ??

 

I think posted tire pressures are low enough to provide comfort but high enough to assure safety. I run mine 10 psi higher than posted for mileage and with 23,000 on the Michelins that came on the truck there is no abnormal wear. I just did a side to side rotation today and in 5,000 miles I'll do the front vs rear swap.

 

tire pressure can/should change depending on the size and load of tire installed if not stock.

use this tool very handy in getting the tire pressure in the right ballpark when installing a different size or load rating vs what the truck came with stock.

 

Be mindful of the temperature of the tires. Pressure should be set when cool and reset during the year as temps change, bout every 3 months or so for optimal performance.

 

That site has limited size choices and the links in it are malicious.

 

Ive used the tool for years, hit no links from it and never an issue. You input the tire size data, so no limitations there.

If you dont like that one, search, there are other pressure calculators out there, find one you like

 

I entered my truck, it gave me almost every size BUT the 295/70/18 I have, I clicked around looking for a way & it locked up my computer with the MS we detected a problem call 888scamyou & I had to kill Chrome.

Sorry if you are offended by reality.

Also, I got the 42lbs I need for my Cooper ATX3XTs from Cooper.

Also, there is no pressure data there.

 

https://youtu.be/W0qL20nBNRI?si=8C5mKSORQSCj4psE

 

For a slightly more in depth explanation as to what and why, look at Toyo's load inflation table. Essentially, find the stock tire size and reference the load @ PSI given on the door sticker (33psi), then find your new tire size and look for the same load (or slightly higher) and the table with tell you what pressure you need to run.

https://www.toyotires.com/media/pxcjubjs/application_of_load_inflation_tables_20200723.pdf

 

FWIW, I did the chalk test & came up with 42-43lbs & then asked Copoer who said 42