infulleffect

Greetings All,

I've been searching to night for recommended tire pressuresm for over sized tires. I just can not seem to find any concrete threads on what folks have found to work in each application for best wear.

I recently upgraded my wheels and tires to 18 x 9 KMC wheels with Toyo Open Country M/T tires (33 x 12.5 x 18). On initial install I had them at 60 psi since I was doing a lot of towing, I dropped them to 50 psi once we got hit with some snow and ice and wouldn't be towing...

What psi will get me the best wear with these tires...any insight? My brother-n-law who is running 35 x 12.5 x 17's on his 2500 (same tire) thinks I should be at the 40 psi range...that just seems a little low for my liking.

Your thoughts and suggestions are appreciated.

Thanks,
Jim

busta

at the tire shop we run 10 psi under what is called for when they are in stalled

matego

Weigh each axle of your truck and call the tire mfg and get their recommendations. I did that with my 12.5x35's and what they told me was right on. I have had very even tire wear with about 30k on the clicker.

dozer12216

Very good advice as they know what psi will support.

.boB

The tire needs to have enough pressure to maintain a flat contact patch. That's really all there is. But the pressure needed will vary according to things like load, temp, speed, altitude, etc.

There's two fairly accurate ways to find it. First, get the tire to operating temp, and park on a flat surface. Use black board chalk, and mark a patch of the tread, from one side to the other. Drive forward about a truck length. Look at the chalk marks. If it's evenly worn across the tread, pressure is perfect. Light in the middle, and pressure is high. Light on the edges, and pressure is low.

The other method is to use a tire pyrometer. Look for an even temp across the tread width.

infulleffect

Thanks for the advice...I like the chalk idea...maybe when all the snow and ice mixes are done I can give that a shot...the weighing option has cuaght my attention, how the heck did you weigh each axle?
Until I can try these other methods I will air up to about 55psi (which is 10 under the recommended psi) and roll from there and plan on rotating them every 5000 miles.

Thanks

matego

Usually the CAT scales at truck stops have split scales. I think it costs 3 or 5 bucks, IIRC.

SCCSURF

I run the same tires but with 37" height. I deal with snow and ice everyday and keep mine at 50 psi all around. It all depends on your load, temp and road conditions. Best advice is the chalk test, it works. Remember the lower the pressure the more grip and less MPG's, and the higher the psi less grip and more MPG's.

DODGER BOMBER

i was runnin 35 in my 39.5" iroks ad 45 in my 37" Procomps and my BFG A/Ts