Tire wear front only

[DA BIG ONE]

I'm running 285/75/16 MTR's, my frontend is tight as it's ever been and I'm getting a cupping type wear on my front tires only, wear seems to be about the same and uniform on both tires and evenly spaced. The leading edge of each lug is now taller than it's trailing edge. Back tires do not show this wear pattern.

At this stage I'm thinking shocks (bilstein w/ 20k on em) can't handle these big tires, so dual shocks come to mind unless I can get some changes in shock valving that may help, but I don't know enough about shock valving to decide. I have a triple shock hoop setup that I 've not installed yet which allows running 2, or 3 shocks depending upon need.

[rjschoolcraft]

How many miles?

When was the last alignment?

Every 4X4 that I've ever owned will cup the front tires if rotations are not performed at regular 5,000 mile intervals. If alignment is off, the cupping is accelerated.

[DA BIG ONE]

Originally posted by ronniejoe:
How many miles?

When was the last alignment?

Every 4X4 that I've ever owned will cup the front tires if rotations are not performed at regular 5,000 mile intervals. If alignment is off, the cupping is accelerated. Hello RJ, Just aligned last month, about 4k on tires, not rotated yet.

I will get that alignment checked out again. I'm running 60psi frt/back as the alighment shop suggests.

Thanks.

[Dvldog 8793]

Howdy
I would have them look at the idler arm as these trucks seem to eat idler arms for lunch. Also of the three chev trucks all have had the alingment changed to run a more "flatter camber"??? I'm not sure about the terminology, but it really seems to help on tire wear.
L8r
Conley

[G. Gearloose]

I personally run just nuetral to 1/8" toe-in, and aligned at a shop I trust. If the holes havn't been punched out, its never ben truely aligned. My 285's appear to wear clean.
RS9000 shocks help too, I can set the damping where the truck wants it;
I suspect the toe-in is most responsible.

[DA BIG ONE]

Originally posted by Dvldog 8793:
Howdy
I would have them look at the idler arm as these trucks seem to eat idler arms for lunch. Also of the three chev trucks all have had the alingment changed to run a more "flatter camber"??? I'm not sure about the terminology, but it really seems to help on tire wear.
L8r
Conley Has brand new factory 2 piece idler arm.

[DA BIG ONE]

Originally posted by G. Gearloose:
I personally run just nuetral to 1/8" toe-in, and aligned at a shop I trust. If the holes havn't been punched out, its never ben truely aligned. My 285's appear to wear clean.
RS9000 shocks help too, I can set the damping where the truck wants it;
I suspect the toe-in is most responsible. They are punched, I'm having them recheck the alignment.

I do have an aftermarket front bumper, and 12,000 lb rated hydro winch up front so I'm thinking the shocks can't deal with the extra weight.

[rlvelin]

Its probably the shocks, when I worked at a tire shop we found that cupping was usually due to bad shocks when all the rest of the front end checked out. Even sometimes when there were other problems in the front end the cupping was caused by shocks. In your case, your shocks may be good but their damping may not be enough for all the extra weight on the front.

[DmaxMaverick]

Bad or underrated shocks can cause cupping. Are you sure you do in fact have cupping?

If the "cupping" is even all the way around the tire, and on every lug, it is not cupping. It is very unlikely you can tell with only 4K on it. Cupping, when caused by shocks, is when there are uneven [flat] wear spots at random, or spaced locations on the tire. Poor balancing can cause a similar effect.

If every lug is worn more on one side than the other, it may be normal for that tire design, and can be exaggerated by heavy braking, by your description. This is why rotation is so important, and will compensate for the nature of lugged tread tires.

285/75/16 D rated tires have a capacity of 3305# at a max pressure of 65 PSI. Your front end isn't going to get heavy enough (you hope) to use all that capacity. A more realistic pressure, even when fully loaded, is 45 - 50 PSI. The overpressure may have something to do with excessive uneven wear. For the rears, adjust pressure as needed for the load at the time. Many folks here, and other places, preach max pressure for max economy. Whatever economy you gain won't offset the shorter life of tires.

What wheels are these tires mounted on? Wheels that are too narrow, or too wide will cause poor tire wear characteristics.

I've used up several sets of 285/75/16's of all flavors on different trucks (my '01 2500HD is on the 2nd set, and ready for the 3rd), and MT's wear exactly like you described. A/T's do also, but at a much less noticeable rate. Deep lugs will do that. Just make sure you rotate them at around 5K and that will be the most you can do. Goodyear MTR's I've used seem to wear much faster than other brands of MT's. Good tire, but too much $$ for the wear.

Click on the "truck stuff pic's" link in my sig to get a look at what I've run. Currently, I have a set of A/T's on, and it looks like I'll get 55-60K on them. The MT's went about 36K.

[DA BIG ONE]

Originally posted by DmaxMaverick:
Bad or underrated shocks can cause cupping. Are you sure you do in fact have cupping?

If the "cupping" is even all the way around the tire, and on every lug, it is not cupping. It is very unlikely you can tell with only 4K on it. Cupping, when caused by shocks, is when there are uneven [flat] wear spots at random, or spaced locations on the tire. Poor balancing can cause a similar effect.

If every lug is worn more on one side than the other, it may be normal for that tire design, and can be exaggerated by heavy braking, by your description. This is why rotation is so important, and will compensate for the nature of lugged tread tires.

285/75/16 D rated tires have a capacity of 3305# at a max pressure of 65 PSI. Your front end isn't going to get heavy enough (you hope) to use all that capacity. A more realistic pressure, even when fully loaded, is 45 - 50 PSI. The overpressure may have something to do with excessive uneven wear. For the rears, adjust pressure as needed for the load at the time. Many folks here, and other places, preach max pressure for max economy. Whatever economy you gain won't offset the shorter life of tires.

What wheels are these tires mounted on? Wheels that are too narrow, or too wide will cause poor tire wear characteristics.

I've used up several sets of 285/75/16's of all flavors on different trucks (my '01 2500HD is on the 2nd set, and ready for the 3rd), and MT's wear exactly like you described. A/T's do also, but at a much less noticeable rate. Deep lugs will do that. Just make sure you rotate them at around 5K and that will be the most you can do. Goodyear MTR's I've used seem to wear much faster than other brands of MT's. Good tire, but too much $$ for the wear.

Click on the "truck stuff pic's" link in my sig to get a look at what I've run. Currently, I have a set of A/T's on, and it looks like I'll get 55-60K on them. The MT's went about 36K. I'll drop the pressure to say 45/50 up front.

I understand what cupping looks like and you are right mine are not cupping.

The tires are on Alcoa 16x7, and seem to wear faster than I like.

[ 01-23-2006, 10:48 PM: Message edited by: DA BIG ONE ]

[damork]

G. Gearloose is right on target. I bought my truck with low miles after the first owner had just put a set of Michelins on it. He gave me the alignment results and told me to never follow the factory specs, but to use minimum toe in and as little camber angle as possible. That set of tires went 110k and the second set is on course for a repeat (new alignment with new tires). Shocks are Bilsteins.

I had one heck of a time finding an alignment shop that would work with me, but when I did the guy new exactly what I was talking about and dialed it right in. You have to be willing to walk away if they won't give you what you ask for.

[DmaxMaverick]

The allignment is important. Even if your allignment is perfect for your conditions, MT tires will still wear like that. It's the nature of the beast. That is why it's important to rotate.

On the allignment spec....
Most of my driving is on mountain roads. For the last 15 years, or so, I've always had my camber (on all vehicles) adjusted to 0, and reduced the toe in. The result is better wearing tires, but a trade-off of less desirable control on the highway. I live with it, and my tires wear even.

DBO
If your ONLY wear concern is the uneven lug pattern, DO NOT change your allignment. Doing so will exaggerate an already normal wear pattern. Adjust tire pressure to give the most even pattern (accross the entire contact area) and traction. Reducing camber or toe-in will effect highway control quality. The advice in above posts is good, but is more specific to individual driving needs.

BTW: A 7.5"+ wide wheel is recommended for 285/75/16 tires. Your 7" wheels are probably just fine, but may make any of the other parameters less than optimal. Some folks run them on stock PYO's (16/6.5") with no serious problem.

[rjschoolcraft]

Shortening the rotation interval will help this problem.

[DA BIG ONE]

Originally posted by DmaxMaverick:
The allignment is important. Even if your allignment is perfect for your conditions, MT tires will still wear like that. It's the nature of the beast. That is why it's important to rotate.

On the allignment spec....
Most of my driving is on mountain roads. For the last 15 years, or so, I've always had my camber (on all vehicles) adjusted to 0, and reduced the toe in. The result is better wearing tires, but a trade-off of less desirable control on the highway. I live with it, and my tires wear even.

DBO
If your ONLY wear concern is the uneven lug pattern, DO NOT change your allignment. Doing so will exaggerate an already normal wear pattern. Adjust tire pressure to give the most even pattern (accross the entire contact area) and traction. Reducing camber or toe-in will effect highway control quality. The advice in above posts is good, but is more specific to individual driving needs.

BTW: A 7.5"+ wide wheel is recommended for 285/75/16 tires. Your 7" wheels are probably just fine, but may make any of the other parameters less than optimal. Some folks run them on stock PYO's (16/6.5") with no serious problem. Thanks for the advise.

I've lowered the pressure to 50lbs frt/back steering in now more to my liking ride is better too, will try 45psi @ frt.

I tried the chalk method over a large area of tread at different pressures to see pattern on tires w/o any luck because the chalk wore off at the highest pressure.

[DA BIG ONE]

Just rotated tires front to back and found feathered wear pointing towards the center of my burb on the front tires which I could not see clearly with tires on truck, "tow in problem" for sure, I am pis%@# off at this stage.

[Barry Nave]

I am pis%@# off at this stage.

Like thats going to help tongue.gif :D
Hang in there,your so close to having the best front end out there ;)

[DA BIG ONE]

Originally posted by Bnave95:
I am pis%@# off at this stage.

Like thats going to help tongue.gif :D
Hang in there,your so close to having the best front end out there ;) Your right, why get twisted out of shape? Small issue when compared to other things that have gone, or could go wrong.

[gmenor]

I would also look at adjusting the steering box - maybe loose.

[DA BIG ONE]

Originally posted by gmenor:
I would also look at adjusting the steering box - maybe loose. I've been through steering boxes like there is no tomorrow, everyone says they are not adjustable. GM seems to have the only replacements remanfactured they claim.

I wonder why they go bad so fast?

What is best way to adjust it, wheels off floor, or?

[gmenor]

I had the front end off the floor. Have someone hold the steering wheel with it in the locked positon (key out) to the right or left. Pull the the tire left and right. There should not be any movement, if there is then the steer box needs to be adjusted. I had about two inches of movement either way. This is why my tires are cupping.