Tire Cupping

[cajung]

I brought my 2X4 2000 Tahoe in to have the tires rotated and get a lube job today. The Tahoe still has the original tires (Firestone Wilderness LE) that have 8/32 tread and are all in good shape. I always make sure the tires are properly inflated (35 lbs) and have front end alignments regularly. My last tire rotation was 8,000 miles ago. The tech looked at my tires and said that they were cupping on the inside of all 4 tires. I could see it for myself also....not just the front tires, but the rear tires also. What could cause this? I'm the original owner of the Tahoe, which has 43,000 miles and I have always kept up with maintanance. The Tahoe has never been in any accidents either. Does anybody have any ideas what would be causing this? Thanks

 

[667theneighbour]

Take a look here:

http://www.partsamerica.com/Maintenance/MaintenanceTireProblem.aspx

 

[boostaholic]

Rotate the tires every 5000, the rears cannot cup unless you bent your axle. Check the pitman/idler arms for any play since these trucks commonly have issues with them. Could also be a unit bearing (hub assembly that the wheel bolts onto). I rotate my tires every 5k and have some play in the pitman/idler arms, tires are wearing evenly with no issues.

 

[cajung]

Rotate the tires every 5000, the rears cannot cup unless you bent your axle. Check the pitman/idler arms for any play since these trucks commonly have issues with them. Could also be a unit bearing (hub assembly that the wheel bolts onto). I rotate my tires every 5k and have some play in the pitman/idler arms, tires are wearing evenly with no issues.

I'm wondering if the shocks could be causing the cupping problem. That is the only thing I can think of that would be common to all 4 wheels that would cause cupping. I never bent the axle...the Tahoe has never been in an accident to cause that. The car is 9 years old and has 43k on the odometer. Could all four shocks wear out in that amount of time with only 43k miles? Thanks

 

[667theneighbour]

I had to change shocks, front hubs and rear brake discs before reaching 37k miles so I guess anything can happen.

 

[cajung]

Forgot to mention that I have the ZW7 Premium Ride option. Thanks

 

[boostaholic]

Shocks could cause the issue, it will be a small, choppy pattern on the outside of the tire. You could try pulling one of the shocks to make sure it isn't leaking/play in bushings.

 

[Big Tap]

My tires did something similar because of the idler and pitman arms being shot. I rotated them frequently, but it still did it to them, just in an even manner. As Boost said, it's a common problem that doesn't cost a lot to fix, but can cost a lot in tires if you don't take care of it.

 

[cajung]

Shocks could cause the issue, it will be a small, choppy pattern on the outside of the tire. You could try pulling one of the shocks to make sure it isn't leaking/play in bushings.

It does seem like a small choppy pattern on the outside 1"-2" edge of the insides of all 4 tires.

 

[cajung]

Brought the Tahoe in and the tech said that the front end looks great. He also said that with the ZW7 Premium Ride option that he has never seen the rear shocks go bad at 43,000 miles and added that they go well past 100,000 miles....easy. Although he didn't see any signs of the front shocks being bad (fluid leakage from the shocks), he thought to be on the safe side that it would be a good idea to replace them. Any comments?

 

[Virginia Donkey]

I am having a similar problem on my '02 Tahoe. I have feathered wear on both inner and outer edges on the tires. My pressure was set to 35psi. my mechanic said that is too low on this size vehicle, to run them at 45psi. So I had them check the alignment (it was good) and pump up the tires to 45.

My tires are Firestone destination LE's. maybe its just a Firestone thing

 

[cajung]

I am having a similar problem on my '02 Tahoe. I have feathered wear on both inner and outer edges on the tires. My pressure was set to 35psi. my mechanic said that is too low on this size vehicle, to run them at 45psi. So I had them check the alignment (it was good) and pump up the tires to 45.

My tires are Firestone destination LE's. maybe its just a Firestone thing

I have the same tires on mine and they're holding up really well. In fact, when it comes time to replacing them, I plan on buying them again. Maybe I'll replace the front shocks and raise my tire pressure to 40psi.

 

[boostaholic]

I'd replace the shocks with some nice bilstein HDs if you're gonna buy new ones. I ran my tires at 34 psi for 6 months and never had an issue, rides a bit stiffer at 40psi but the fuel economy went up and they should wear better.

 

[cajung]

OK....I just replaced the front shocks. Is it at all possible that an alignment problem may be causing the cupping off the tires. I don't think so but I'd like some other opinions. Like I said before, The front end components were checked and everything looks good.

 

[cajung]

bump.....

 

[slmmdgmc]

the problem is the tires..... all gm suv's 00 and newer have had the same problem. usually cupping on the outside or inside edge will be due to toe being out. i work on these daily. i would recommend shocks and get ride of the tires. shocks i would recommend are kyb mono tube... they will eliminate body roll....

hth

 

[cajung]

the problem is the tires..... all gm suv's 00 and newer have had the same problem. usually cupping on the outside or inside edge will be due to toe being out. i work on these daily. i would recommend shocks and get ride of the tires. shocks i would recommend are kyb mono tube... they will eliminate body roll....

hth

Thanks for your reply. All the front end components look great. I had the front end checked for alignment and it was perfect.....dead on. I just put on new shocks so I guess that is all that I can do. I've only got 43,000 miles on the tires (original) now. I would like to put on at least another 7,000 miles before getting new tires as there is still a lot of tread left on theses. Would there be a safety issue with that?

 

[slmmdgmc]

u wont have any problem, just tire noise.... i recommend to my customers to rotate tires every other oil change.

 

[cajung]

I've only replaced the front shocks. I have the ZW7 Premium ride option and the mechanic told me that he wouldn't bother changing the rear shocks because they will easilly last well over 100k miles. I hope he's right.