Tire pressure
Senior User
Joined: Nov 2008
Posts: 200
Likes: 13
From: Sheridan, Wyoming
Thats because there is no set answer. If you want to know what pressure then inflate them to 35PSI, get a piece of chalk and draw a line straight across the tread. Drive it around the block, if all of that chalk line is gone, you are good. If there is still some on the edges, you are underinflated. If there is still some on the center, you are overinflated. Play around with your pressures until you get it right. I ran my 31x10.50x15 tires at about 35-37PSI. That worked best for my truck and tires I had. Your's may be and probably will be different depending on truck wieght and tire.
Chris
Chris
Senior User
Joined: Jul 2010
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Chalk idea is fine but I think he meant the other way round.. chalk on the outside edges is overinflated.. Best way is with a pyrometer but hey... these are big tires so the chalk should be fine. I run 41lbs with 35x12.5
Senior User
Joined: Nov 2008
Posts: 200
Likes: 13
From: Sheridan, Wyoming
How many people have a pyrometer laying around? I am almost 50 and have been working on vehicles, my own and others, for 35+ years. I don't have one and never felt the need to have one.
Chris
Senior User
Joined: Mar 2010
Posts: 459
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From: Fayetteville, NC
uumm yea, if its over inflated the chalk will be missing from the center of tire.....leaving some on the edges.....
under inflated will leave chalk in the center and remove it from the edges first.....
neat idea, ive never heard of it but it makes perfect sense...
under inflated will leave chalk in the center and remove it from the edges first.....
neat idea, ive never heard of it but it makes perfect sense...
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FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
Actually I think you did get it backwords, if there is chalk remaining on a certain area of the tread then that means it's not in contact with the road. No contact on the outer edges is an over inflated condition, while no contact in the center is under inflated.
The chaulk method is a good one and it's purpose is to maximize tire contact which maximizes traction, and on a pickup you may also notice that the rear requires less pressure than the front to achieve the optimum contact patch.. particularly with reg cab truck.
The chaulk method is a good one and it's purpose is to maximize tire contact which maximizes traction, and on a pickup you may also notice that the rear requires less pressure than the front to achieve the optimum contact patch.. particularly with reg cab truck.
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Senior User
Joined: Nov 2008
Posts: 200
Likes: 13
From: Sheridan, Wyoming
My mistake, I did get it backwards. Sorry about that gentlemen. My head is bowed and bloody ;D
I consider my toolbox pretty well equipped with no pyrometer in sight. I can see the uses for one but have never seen the need for it in the work I have had to do. Now that the price on them has come down I may get one though. At least to see if the wife is ready, lol. Most specialty tools can be gotten around in one way or another. Some can't.
Chris
I consider my toolbox pretty well equipped with no pyrometer in sight. I can see the uses for one but have never seen the need for it in the work I have had to do. Now that the price on them has come down I may get one though. At least to see if the wife is ready, lol. Most specialty tools can be gotten around in one way or another. Some can't.
Chris
Senior User
Joined: Jul 2010
Posts: 215
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haha.. I feel ya, we all have those moments... notice I left my age out! LOL. I drive an AMG for fun and find that little tool particularly useful at the track for all kinds of readings. Coolant, ac discharge temp, trans temp, rotor temp.... you get the idea. If you don't have one I highly recommend 1 if not just for the curiosity factor.
Senior User
Joined: Nov 2008
Posts: 200
Likes: 13
From: Sheridan, Wyoming
I ain't giving my age out but its between 46 and 48, lol. I like to blame my age for those momentary lapses in memory, gotta blame it on something anyway 
I might go get one but I doubt it. The only vehicles I work on anymore are my own.
Chris
I might go get one but I doubt it. The only vehicles I work on anymore are my own. Chris
Posting Guru
Joined: Oct 2009
Posts: 1,431
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From: Ohio
haha.. I feel ya, we all have those moments... notice I left my age out! LOL. I drive an AMG for fun and find that little tool particularly useful at the track for all kinds of readings. Coolant, ac discharge temp, trans temp, rotor temp.... you get the idea. If you don't have one I highly recommend 1 if not just for the curiosity factor.
What year and flavor AMG? I'm a Mercedes nut...
Posting Guru
Joined: Oct 2009
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From: Ohio
87 560sl...I do the same thing. I've had domestic sports cars in the past, but nothing near as nimble and fun as this. It's a completely different beast with the hard top off.