So here’s a rather stupid question, but tires are expensive and I want to make sure they’re correct. I just got brand new cooper discoverer at3s put on. I know inside the door jam it says for 275/55/20 tires to set the cold pressure to 35… that just seems kind of low to me looking at them they look kind of low and they’re set to 38lbs currently. The original hankooks I got 50K out of and kept them near or at the 35psi range. Just want to make sure the same is recommended for this different tire as the shop that mounted them had like 44lbs in them.

 

You can do the chalk test and get the best pressure. Basically you take chalk and rub a patch about 12 inches long across the entire width of the tire at 35psi, drive the truck in a straight line (no turning at all) 4 or 5 rotations of the tire. Get out and look at the chalk, did it wear evenly? Now add a1 or 2 psi and repeat the chalk test, when you start noticing the center of the chalk wearing and the sides are staying fully coated you are riding with to much pressure. If you have the opposite (at your lower pressures), outsides wearing and center staying good, then you are running to low of pressure.

 

Please provide the size specifications of your new tires. Are they SL or D/E rated tires? Only foolproof way to determine proper pressure for your new tires is the "chalk test" (google it). I have 275/60/R20 SL and they are happy at 38#.

 

they are 275/55/20

 

Also assuming you have stock wheels?

 

yes they are the stock 20s that came on my 18’ lariat

 

Duplicate.

 

What they are asking you other than size ARE TIRES S/L XL OR THE PLY RATING
Explanation: SL= standard load XL= extra load or the tire ply rating which could be C D or E & tire size will start with LT 275/55R20

First go by the suggested tire pressure on your door plate......that is usually SL (standard load)
2nd XL rating can go as high as 44lbs (it will say 44lbs on the tire) but you can run less !!
3rd Different ply's dictate "maximun" tire pressures C= 50 lbs D = 60lbs & E = 80lbs
PS: your tire pressure @ 38lbs is probably right on for a smooth ride.....however some put in extra (say 40 lbs) this will decrease your ride but will also stiffen up cornering etc.
"Do the chalk test " or try the 40lbs & road-test....1-2 lbs over the 38 will not likely make a noticeable difference in wear but it will be a stiffer ride on cornering etc.

 

 

According to what you initially posted (275/55/20) that is a SL rated tire commonly called a "P" metric....
The tire you posted above is A XL rated tire....that is ok as a replacement tire for your trk......XL rated tires can carry a little more load (read the weights on sidewall of each tire) & also can put up to 44lbs in them to accomodate your loads etc.........
AS I stated in my last post it has a rating "XL" & is suggested max tire pressure is 44lbs maximum...... (this is also on the tire).......... But you put in what is best for your needs !!!....Again 38-40 lbs would probably be a good tire pressure for you ??