Cupped Tires

[dp88]

My sterring wheel was shimmying a while back thought I fixed it by getting all the mud out behind wheel and rotating tires to back. well the old fronts that are now on the back are cupped in the center I noticed. I can feel a vibration from the rear of the truck but no more shimmy after I rotated them. My shocks seem fine and the tires were within 4 psi of recomended pressure. This kills me bc those tires were almost $800 and if to are already cupped I'm screwed....
I dont know what to do...

 

[JohnnyO]

Have the suspension, alignment, and wheel balance checked out. Otherwise just rotate the tires every 3000 miles and the cupping will go away. If it's only the two tires that you now have on the rear that are cupped, just leave them there for 5000 miles.

 

[straycat]

Get thoose shocks checked out as well. They can give you some cupped tire wear as well......

 

[dp88]

They are the bilsteins and they really feel good. The truck feels great on the road other than the vibration coming from the cupped tires in the rear I believe.... I did air down real low driving home one day bc roads were covered in ice... could that have caused some of it?

 

[martin]

wear in the centre is caused by overinflation. wear on the edges is caused by underinflation.

 

[straycat]

They are the bilsteins and they really feel good. The truck feels great on the road other than the vibration coming from the cupped tires in the rear I believe.... I did air down real love driving homw one day bc roads were covered in ice... could that have caused some of it?

How old are the shocks, Bro?? I replaced my 5100 'steins after 5 years.
Most shocks that see any offroad use don't last but 5-6 years. Most of the offroad mags I read say the same thing...if you do see any leakage on a shock replace it of course...but you can do the compresion test on the shocks and see if they are releasing like they are supposed to.

My 5100 series are for lifted suspensions (6 inch front and 4-5 inch rear). This is my second set of shocks and my second set of 33 inch KO tires. The 5100 series are really great but they don't last forever!!!! I do know some people who run their shocks for years and years....and I can tell when ever I go someplace with them.......bounce, shimmy, jerk, pull, pull....lol

 

[dp88]

oh they are 8 years old......

 

[Original_Ranger84]

Yeah you should replace the shocks... I had the factory shocks on my new truck, or they looked like the factory shocks and were wearing out the inner blocks on my tires cause they can't keep the tire on the ground while cornering, and it will wear out every other block.... Rotated the tires and replaced the shocks and it wears just fine. The old shocks didn't feel like they were worn out at all but there is a big difference.

And rotate your tires. Tires automatically round out on the front because when you corner the stress goes to the outside edges, while on the back even if they are at recommended pressure or like 35 will wear out in the center because you have less weight in the back (Aka empty bed in back vs full engine in the front.) the engine will push the whole tire on the road and give full contact while the back is not weighed down so the center makes contact. This is why if you look on your door sticker it calls for like 32 psi in the front while they only call for 30 in the back.

 

[dp88]

I just turned 40,000 mile on my truck... and I just rotated my tires they were getting cupped in the front so I had to move them.

 

[LearjetMinako]

Cupped tires are an indication that either the tires are over inflated and/or the shocks are going or have worn out. Mostly, its the shocks that will cause that problem. Also to note, bigger tires do put a larger load on the shocks. One reason why they wear out faster too.

 

[dp88]

you really think after 40,000 miles they would be worn? I dont bounce around and the truck is still stiff... That sucks bc Im broke putting all my money to pay for college.

 

[Original_Ranger84]

you really think after 40,000 miles they would be worn? I dont bounce around and the truck is still stiff... That sucks bc Im broke putting all my money to pay for college.

Yes... Its recommended you check or replace them every 20,000 miles or so they say but I figure you can get 40 or 50,000 miles off a pair of shock. Mine felt fine and tight but the tire told differently... They were wearing on the inside every other block... I rotated the backs to the front and replaced the front shocks and there is no sign of odd wear on them, the shocks felt fine but they were bad.

 

[Toms01PSD]

My last 99 had the original shocks on it for 180k miles. When I put Bilsteins on there, it was a world of difference.

 

[JohnnyO]

Yes... Its recommended you check or replace them every 20,000 miles or so they say but I figure you can get 40 or 50,000 miles off a pair of shock.

The older hydraulic shocks were good for 20,000 miles tops. Gas shocks are good for 40 to 50,000 miles.