Tire Pressures

[Joe Mc]

Just caught EMDDIESEL's "Tire Rotation" thread. Brought to mind a question I had about pressure. I have 265/75/16's and thought of running them @ the door jamb sticker values for the 235's. But, after considering things I thought 80# rear and 65# front was kind of high, so I went with 76# rear and 60# front. Not much lower I know but. . . . ? That's what this site is for . . . what works best for you all, with similarly sized tires?



What are the best across the road values with the size I'm running since we're going to Yellowstone in a few weeks. Let me have it

 

[roadranger]

Hauling around what I do, the pressures on the 265's are;

front 75 psi

rears 80 psi



This gets me to maximum weight handled, and the tires don't look 'soft'.

 

[WyoJim]

Joe, are you towing or hauling anything to camp in or staying in motels?

 

[larryq]

I was told By Ted Janetty to run the front at Max Pressure at all times. .



After all the 6 cylinder DEMON weighs a bit more than the standard V-8!



Rears are a differant story...

But I still run on the high side for improved mileage.



I got 60,000 out of the OEM Michelins so I must be doing something right.

 

[RottnDogue]

285x75

How many lbs? I think I'm @ 50, but can't remeber now I'll have to check in morning.





Darren

 

[Fireman Dave]

I follow the little tire chart that came with my manual. Empty, I run 55 ft, 45 rear - which is 5 over the chart recommendation on each end. I find it steers better on the highway with the lower front pressure when empty. When towing, I go up to 65 front and 75 rear. 80 all the way around might not be a bad idea when towing, so I might try that next time out. My tires look good after 18k (and regular rotation). I have 265s.

 

[Deezal Man]

I'm sorta in line with Fireman Dave,



If the truck is empty, run the front tires higher than the rears. This applies for almost any vehicle. Other than improving ride, it reduces the amount of built in oversteer. Thus making your vehicle feel more agile. Higher rear pressure increases oversteer and makes it feel mushy. Guess it depends what you prefer.



My preference is 65F/55R. The factory Goodyears worked well at 65F/45R



IMO, rear tires at 80 psi empty are borderline dangerous.

Not a great feeling to have the rear jumping around from pavement joints or bumps. Additionally, rear braking is compromised in that the tire has less bite into the pavement. Chances are, your rears will not wear evenly at this pressure.





Loaded is a different story. Rears should be at max pressure to reduce tire heat and provide even wear. In this situation I run 70F/80R.



Putting all the advice in the world to the side, you really need to monitor the tires in how they wear.



This link provides good information about various tire wear conditions.



http://www.tirerack.com/tires/tiretech/sidewall.htm

 

[rono]

I currently have 28k on my factory Michelin's and for some time they have been showing more wear on the outside edges. I run empty 99% of the time and rotate at 6k. I have been increasing my pressure from what it was when I bought it and am now at 65F and 55R, trying to even out the wear. There is plenty of tread on the rest of the tire and all 4 seem to be wearing evenly except on the outside edges. It looks like I should get at least 25k more if the edges don't wear out first. Should I go higher on the pressure?

Ron

 

[SLVRBLT]

I don't have the owner's manual in front of me, but seems like it says for the 265 Michelins that the max. pressure for full load is 55 front, and 70 rear, with 70psi being the max for this tire.



I usually run 50 front and 50 rear when empty. I have about 11,000 miles on them, have rotated them once and they look great. When I made a test run in the new 5er a couple of days ago I ran the rears up to about 65 and they looked fine with the trailer on? Will probably go to 70 when I go for a real trip with all the fuel tanks full.



Dave

 

[FDziurda]

Quite some time ago, someone posted a very logical way to determine the best tire pressures.



Have your truck weighed at a certified scales and note the front and rear axle weights. Look at your tires to determine their load rating. The factory 245 Michelins on my 99 are each rated at 3042 lbs @ 80 psi. My front axle weighs 4,300 lbs and the rear weighs 3,300 lbs.



To determine the correct tire pressures, take the combined load rating of the two (or four if a dually) tires and divide it into the actual axle weight, then multiply it times tire max load rating psi. As an example, my front axle calculates as 4300/3042x2 or (4300/6084) x 80 psi = 56. 5 psi. My rear axle weighs 3300 lbs so (3300/6084) x 80 psi = 43. 4 psi. I run 60 lbs in my fronts and 45 in the rears and have almost 40K miles on the tires and they are wearing perfectly even. This method also works nicely for towing but you need to have your rig weighed with the loaded trailer/5er attached.



Good Luck!

 

[RottnDogue]

Right now they are 51 front, 45 rear... ... 45 in rear and it's a pogo stick, can't imagine 65 or more unless loaded and trailering.



FDziurda

I will check that formula, and see where I should be, If I had to guess I'm pretty close. Might need a few in front. Thanks





Darren

 

[FDziurda]

RottnDogue



My truck is a 2500 and has a 600 lb steel camper shell on it and some tool boxes in the bed to get the rear axle weight up to 3,300 lbs. I'd guess that a completely empty 2500's rear axle weight would be somewhere around 2600-2700 lbs, and would probably only need 35 - 40 lbs in the rear tires.



After setting the tire pressures, look down the side of the truck and compare the amount of sidewall bulge between the front and rear tires (they should look exactly the same).



Good Luck!



Frank