Question How many PSI on my FJ rims & tires?? - Toyota Tundra Forums : Tundra Solutions Forum

stevebaum · #1 (**permalink**) 10-21-2009, 09:33 PM

I have a new to me 03 Tundra AC SR5 2WD, V8 (no TRD). The previous owner needed new tires on the truck before he sold it and bought an almost new set from a Toyota FJ Cruiser. He told me to run the air anywhere from 38 to 40 PSI, but I'm wondering if that is too high. I'm feeling a lot of minor road imperfections and shake. The rims are 17" and the tires are Dunlop AT20, markings on the tire are P265/70 R17 1135 M+S ( max load 51PSI).
Should I keep it at 38 to 40 PSI or lower it? How will that effect the life of the tire?
BTW, the rims and tires look very good, and I've checked for rubbing on the front suspen. and don't see any.
Thanks in advance, stevebaum

Mr. Creosote · #2 (**permalink**) 10-22-2009, 12:30 AM

If the tire sidewall calls for 51 psi, I would keep it around 40-45 psi.

mytundrarocks · #3 (**permalink**) 10-22-2009, 08:24 AM

if you really want to know do the chalk test. draw a line across the tire tread from side wall to side wall. Roll the truck foward enough to get the line down 2 or 3 times and look at the chalk. If you only see chalk on the outside, they are to soft. if only chalk in the middle they are to hard. you want to see chalk all the way across. I run my load c tires at 50 pounds. Softer tires give better traction but at the cost of wear on the tire and fuel milage.

csawyer · #4 (**permalink**) 10-23-2009, 02:15 PM

Good tip with the chalk line. I never understood how Toyota determines the best air pressures for the tires, because if you look at the sticker inside the driver's door jamb of my truck it says 29psi in front and 32psi in rear?!?!? I had those Dunlop AT-20s as the stock tires and I ran them at 38psi front and 36psi rear and got just over 44,000 miles of even wear out of them. I found that any higher than that and once they heated up and expanded they rode rough and the rear end liked to bounce around. Any lower than that, and the gas mileage and tire responsiveness went down. My opinion is if you do regular offroad driving, you'll probably want them a little on the low side for traction, but if you do mostly onroad, keep them as reasonably high as is comfortable to you so you get less rolling resistance and better mileage.