Tire pressure and tire wear?

[nevinst]

I did a search to see if there was anything on this topic but didn't find anything.



What's the general concensus about tire pressures and what are your experiences with tire wear? When I got my truck (used) it had relatively new tires. I put some fast miles on the truck when I first got it and before I knew it, I had put 35K miles without rotating tires. The rears were already running thin and the fronts were hardly worn.



Is this typical with the heavy front end and light rear end? (Don't tow anything to speak of) Does the short-bed make a difference? Would reducing the rear tire pressure help? (The rears seemed to have worn evenly across the entire width but the difference between them and the fronts was amazing)



I have long since replaced the rear tires and decided to leave the front ones where they were 'till they needed replaced. I have put another 15K on them and they should be good for another 10K at least! It's too early to see any noticeable wear on the current rear tires. I'm running about 40psi and they they seem to be holding up a little better than the first pair.



Any recommendations? Thanks.



P. S. I love this site. Looking forward to BOMBing soon. Ordered a set of guages this morning and hope to have them installed in a couple weeks. Went with AM Ultra-Lite series, Pyro, Boost, and Fuel pressure. Also ordered the three pod A pillar. Any advice on installation would be appreciated.



Oo.

 

[chuck3]

Only rotated mine once in 31000 miles, seem to be wearing about the same on front and rear, I run 65 psi in front and 55 to 60 rear. Looks like I might get another 15 to 20k on them.

 

[nevinst]

Chuck3,



I started off running 50-55 psi on front and 45-50 on rear. Since I replaced the rear tires I have maintained 60psi in front and 40psi in rear. The only difference in handling that I have noticed is that the rear end seems to have a slight "pulling" effect if I steer sharply with any speed (Like jumping out to pass or to swerve)



I guess if I were to haul or tow anything heavy, I should put more pressure in the rears at least. Do you think it is hurting anything to run them this way otherwise?

 

[Dave MacArthur]

If you call the tire manufacturer they will tell you/fax you the recommended tire pressures for different axle weights. I got the spec's from Michelin for my stock 245/75's. They were 55 front and 42 rear empty. That's for a 2500 short bed. About 4500lbs on the front axle and 2000 on the rear. I rotated those about every 7500 miles using the pattern recommended in the manual. Left front to right rear, right front to left rear, and the two on the back straight up front. I had 40K+ on them when I swapped them out for a more aggressive tread pattern. They were in next to new condition all the way around at that time. My experience with pickups is that the rear's will wear out much faster if you run unloaded most of the time and keep the tires at the upper end of their pressure range. It's kind of a pain to have to change the pressure everytime you put something fairly heavy in though. By the way, I see you are running 60 front and 40 rear. If I recall correctly, Michelin told my not to have a pressure difference of greater than some number. I think that number was 15 psi. That may be why you have that slight "pulling" sensation.



Dave.

 

[Michael Hughes]

I run 65 in the front and 55 in the back when empty. When I haul a load of fire wood with the side board on the bed, I run 80 in the back. I tried different PSI's in the front and didn't like the way the truck handled. I wouldn't go below 60.

 

[Gray Ghost]

I run 70# in the front and 50# in the rear. One interesting note,

I got a nail in the right rear one day. Happened to notice the nail

as I was going into the house. Tire looked fine. 0# when I checked it. Ten ply Mich seem to hold up the back with very

little pressure. Another thing, never use a cinder block under

the front A arm. All you get is crushed cement. Did that on

my first rotation many miles ago. That's when I realized how heavy that front is.

 

[WyoJim]

"I have long since replaced the rear tires and decided to leave the front ones where they were 'till they needed replaced. I have put another 15K on them and they should be good for another 10K at least!"



nevinst... Thats about the pressures I run and I don't rotate my tires either, and I am happier than a pig in s**t with my mileage. Not rotating means I only have to buy two tires at a time and 60,000 out of the fronts ain't bad.



Some day when you are on a dirt road start out the same as you do on the pavement and look in the rear view mirror. You will see two tracks your rears are making. Thats where the rear tire mileage dissappears to. My wife won't let me run high pressure in the back tires, it jolts her to much when I make her ride back there.



I bought a tread depth guage and check my tread depth across the tire every oil change and adjust the air accordingly.

 

[nevinst]

"My wife won't let me run high pressure in the back tires, it jolts her to much when I make her ride back there. "



I bet she even complains about the cold Wyoming air while she's back there too!! I spend a few miles out on the dirt roads (mostly blow-sand around here) and know what you mean about the tracks from the rear tires. That back end gets pretty loose when you goose it.



I think I might add a little to the rears (45 maybe) and watch the wear real close. See if that gets rid of the pulling and smooths it out a little. Thanks for the inputs

 

[FDziurda]

Calculating Tire Pressures

Here's a simple way to calculate what your base line tire pressures should be. This was posted on this site many times in the past and I have been using it on my vehicles for a long time. I have >50K miles on my stock Michelins and they still look great.



Weigh your truck to find out what the front and rear axle weights are. I have a long wheel base 4x4, with a 600# steel camper shell on mine: Front axle = 4,300#, and rear = 3,300# Total truck 7,600#, less people.



Look at the side walls on your tires for the load rating @ a certain pressure. My Stock Michelins are rated at 3042# @ 80 psi.



To Calculate the correct tire pressures: divide the axle weight by the load capacity of the tires and then multiply it by the max tire pressure. My Front Axle calculates as: 4300#/6084# x 80 psi = 56. 5 psi.



The rears calculate as; 3300#/6084# x 80 psi = 43. 4 psi. If you have a dually, make sure you use the "dually" max pressure rating and the tire load rating for 4 tires.



I rounded mine up to 60 psi in the fronts and 50 psi in the rears. Use a good quality pressure guage and set the pressures when the tires are cold.



According to the tire websites; you will see about 1 psi pressure change for every 10 degrees in temp change.



Good Luck,



Frank Dz

 

[Pit Bull]

Re: Calculating Tire Pressures

Originally posted by FDziurda

Here's a simple way to calculate what your base line tire pressures should be. This was posted on this site many times in the past and I have been using it on my vehicles for a long time. I have >50K miles on my stock Michelins and they still look great.



Weigh your truck to find out what the front and rear axle weights are. I have a long wheel base 4x4, with a 600# steel camper shell on mine: Front axle = 4,300#, and rear = 3,300# Total truck 7,600#, less people.



Look at the side walls on your tires for the load rating @ a certain pressure. My Stock Michelins are rated at 3042# @ 80 psi.



To Calculate the correct tire pressures: divide the axle weight by the load capacity of the tires and then multiply it by the max tire pressure. My Front Axle calculates as: 4300#/6084# x 80 psi = 56. 5 psi.



The rears calculate as; 3300#/6084# x 80 psi = 43. 4 psi. If you have a dually, make sure you use the "dually" max pressure rating and the tire load rating for 4 tires.



I rounded mine up to 60 psi in the fronts and 50 psi in the rears. Use a good quality pressure guage and set the pressures when the tires are cold.



According to the tire websites; you will see about 1 psi pressure change for every 10 degrees in temp change.



Good Luck,



Frank Dz

Good info Frank, Im going to try that.

 

[RKohn]

I've noticed a definite Weight to Tire Wear correlation...

The heavier my right foot is, the more the tires wear. Oo. Oo. Oo.