Tire tech question

[oh2bnok]

My boss drives a 2007 chebby sierra 4x4 diesel twuck. Auto locking hubs, blah blah Has 47,000 miles on it. His two front tires are wore / cupped on the insides. Took it to the dealer and they checked everything including shocks and they claim everyting is fine. I initially though it may be a bad shocks but shocks feel alright. I have an idea what may have caused the abnormal tire wear, but was looking for some additional input. So I read some 4x4s have tire wear like described which is fairly normal or consistent with the type vehicle. So I ask him if it is 4x4 and he concurs. I explained, then he asks if the wear could be caused from driving it in 4 wheel on the highway for 3 hours at about 70=75 mph ! I'm thinking that it is very possible but not sure

 

[sprdv1]

Very Possible sir... Hmmm..

 

[BobbyA]

If he doesn't rotate them then they will cup also.

 

[needabronco]

I would go ahead and replace the shocks, stock crappy shocks don't last too long.

Also every GM product with that front end I've seen has that problem. My opinion is that they all need the torsion bars turned up so that the control arm is not sitting on the bump stop, and they need fairly regular alignments, I'd say he's due anyway. My theory is that the tire is forced to soak up more of the bumps because the suspension is effectively already 'bottomed' out, thus causing abnormal wear...

 

[67PONY]

Many times cupping on the insides is caused by toe-out. That is, if there are no other signs of wear in the front end components.

 

[Pa PITT]

If this was at our dealership ..I feel like we'd say he should have rotated tires several times ..

 

[oh2bnok]

Dealer says the shocks, ball joints etc are all fine. They don't know. He claims he rotates the tires pretty close to schedule. The torsion bar argument is interesting.

 

[justinoshea]

I noticed similar inside cupping on my powerstroker. I run 315 nitto terra crapplers and rotate every 5000 miles (rear are cupped too).

The tires were all out of balance, and since balancing they seem to be getting less noisy. everything else on the front end checks out good or is new. recently aligned.

 

[hose101]

as far back as 2004 the chevy has a problem with premature tire wear. not every truck is creasted equal and some show worse than others. Currently having a hard time with the dealer covering this on a 2005. He claims all is fine, on the side one of his mechanics says they see alot of this come in. Believes the steering geomotry needs work. No idea what the fix is.

 

[oh2bnok]

Just kinda hard to pin point what it may be. I don't think it is the tires as both front tires have similair wear and both back tires show normal wear. Dealer says they checked everything and only made a slight alignment adjustment. So I am wondering if the 210 miles he drove on the interstate in 4 wheel, caused the wear. I say that because I think the front tires turn at a very slight slower or faster ratio than the back due to gearing and tire size from inflation differences. Just a thought. However I would think the front would be some type of posi trac to get the similiar wear. So back to the suspension geometry, design issue.

 

[deltarat]

Not sure of the reason,since '94 chevs have done this. You need to rotate every 5000 miles and it fixes it. I just rotated every time I changed the oil and did not have the problem

 

[BroncoWyatt]

No, I don't think the driving in 4wd will cause that tire wear. What will cause it is worn tie rod ends, idler arm and pitman arm . We work on a lot of late model GM trucks at my shop, and those are all very common wear parts on GM trucks. I would reccomend he get a second opinion from a reputable alignment shop.

 

[FyreBronc]

If there is nothing worn out (ball joints, tie rods, Idler/pitman arm) the inner tire wear could be due to a camber issue and the cupping could be many things. Make sure that the cupping is not just a saw tooth pattern on the outer edges of the tire. This will happen on a truck's front axle because the front wheels don't always travel straight like the rears. (different arc travel all day long) Cupping will happen all the way across the width of the tire.

Is the truck still on its first set of tires at 47K miles. If not are they the proper load range for a heavy truck? Does your boss carry a heavy load often. Last Air press is the most overlooked part of the equation. I think those trucks are 55psi front 80 psi rear for max load. Just my 2.5 cents. Used to be a Chebby mech. in a dealership for too long........

No, I don't think the driving in 4wd will cause that tire wear. What will cause it is worn tie rod ends, idler arm and pitman arm . We work on a lot of late model GM trucks at my shop, and those are all very common wear parts on GM trucks. I would reccomend he get a second opinion from a reputable alignment shop.

 

[TOOL]

I would check the bearings to.

 

[Nobody]

Rub your hand over the tire in both directions. Does it catch in one direction and slide smooth in the other?

 

[crankman]

I second Bronco Wyatt thoughts, i have seen the tie rods do that very same thing. take it to another shop

 

[cgbexec]

I make it a habit to rotate tires on every vehicle I own every oil change. 3500 to 5000 miles

With the cost of tires, it is cheap insurance.