MT/R tire pressure

[jeepmaster]

i went wheeling today and when it was time to air up the tires again i got into a bit of a disagreement about the appropriate tire pressure to run when back on the road. the shop that mounted the tires suggested i run 40 PSI. the 2 arses that were with me insisted that it should be run at 30-35 PSI. what would you guys reccomend? i have 235/75/15 MT/R's they say on the side of the tire that the max cold PSI should be 50. what do you think?

 

[Sully]

I run mine at 35.

 

[LGR]

I run mine at like 32ish. but they 33X12.5 not sure if its any differnt for other sizes

 

[Junkpile]

It depends totally on the rig they are mounted on. Weight is the biggest factor. Just play with the pressure until you get an even contact patch. You want the weight distrubuted evenly across the tread. Too much air and the tread will wear in the center, too little and the edges will wear faster...either will cause a loss of performance. Ignore what it says on the sidewall, your light little Jeep requires less pressure than a fullsize truck to make the tires work in a similar fashion.

I know alot of people who have gotten bad impressions of tires just because they didn't take time to find the best running pressures. Probably 95% of the time when a person complains about a tire they just purchased they will at least say "I can live with that" after playing with the pressure a little bit.

 

[jeepmaster]

how do i tell what is the best tire pressure for me?

 

[Sound_Man]

The best way to get your tire preasure correct is pretty simple.

Get some "sidewalk chalk" and take your jeep to a level flat spot like a parking lot. Cover about a 12" - 15" setcion of the tread with the chalk and roll forward until the tire has made about 5 or 6 revolutions. Make sure that you are not turning when you do this. Get out and take a look at how the chalk has worn off the tires. if it is wearing of the edges the tire preasure is to low, off the center it is to high. If it is even accross the tire you are probably pretty close to the correct preasure. If it is on one side or the other you need to get it aligned and do it again.

Hope this helps!
~Curt

 

[jps4jeep]

open your drivers door and look on the sticker! It has very little to do with the tire, but rather the vehicles weight!

 

[Sound_Man]

open your drivers door and look on the sticker! It has very little to do with the tire, but rather the vehicles weight!

If they are the same size and type as the stock tires I agree with this. If not do what I posted above to find the correct preasure to run them.

~Curt

 

[jps4jeep]

Removing Roll Bar... Dang Torx bolts

open your drivers door and look on the sticker! It has very little to do with the tire, but rather the vehicles weight!

If they are the same size and type as the stock tires I agree with this. If not do what I posted above to find the correct preasure to run them.

~Curt

Ya I know, He said he had 235-75-15r which is extremely close to a factory size.

 

[Sully]

235-75-15r, isnt that what is on the stock rubicon? If so go to the dealer with a tire pressure gauge and check the pressure.

 

[jeepmaster]

yea it is but the rubi has a 16" wheel. ill do the chalk thing and see what happens. as a side note, i was in the tomken manufacturer showroom today and i asked the guy behind the counter. he suggested 25PSI on the road... that seems really low

 

[Junkpile]

Use the chalk, or whatever you have around that you can mark the tire with. You can paint a stripe across them and watch that wear.....nevermind, just use the chalk. Then you can adjust a couple of pounds for preference. Less air= softer ride but the tires will get hotter and wear faster and gas mileage will suffer. More air= harsher ride but with a slight improvenment in gas mileage and less rolling resistance.

With those tires 25psi is probably kind of low. I'd start with 30 and plan on adding a couple more than likely.

 

[Sound_Man]

I'd start with 30 and plan on adding a couple more than likely.

I will second that.

 

[LadyJeepFreak]

What size does that translate to inch wise? I know I have 31's and I run at 30. They came with more, I aired down and back up a few times and 30 seemed to work for me. Haven't chalk tested though. I've added some weight in mods too.

Lady

 

[Sound_Man]

What size does that translate to inch wise?

Lady

Okay LadyJeepFreak, I gotta ... you opened the door. really really big LOL j/k

try going here http://www.onlineconversion.com/tire_size_conversion.htm

~Curt

 

[jeepmaster]

Jeep Wrangler Husky Back Seat Floor Liner

28.9" lady

 

[TwistedCU]

35 psi should be good on a Jeep for daily street driving. Running them at 40 or 50 psi probably could result in poor rain/snow traction.

 

[White]

Just look at the pressure on the dash guage. See how it rides. Adjust the pressure with the switch.
If its too soft turn it up.

OH Wait, Thats a Hummer. Sorry Disreguard This Reply.

 

[Sound_Man]

That CTIS on the hummers is nice.

 

[LadyJeepFreak]

:shock: That's funny soundman. lol You gave me a laugh, I didn't even think of it when I wrote it all in a hurry.

Thanks for the link, I got it now!

Lady