Cupping causing vibration?

[jiimi]

I just had a lot of work done trying to solve my 60-60mph vibration problem. Its a 92 XLT with 175,000 on it, had the RA bushings replaced, front wheel bearings, and both U-joints. They said i needed new tires, because they were cupped. I figured that it was because i had them underinflated, it smoothed out the shakes a bit. On the way home, i noticed that my truch shook just as much if not more after having all this work done. When i called them up they said that it was because my tires were cupped, and the only way to fix it was to get new tires. I try to rotate ever 3k or so, i need new shocks, front and back. When i got home inflated my tires back up to 35psi, and it helped a bit, but its i definatly don't feel like i got my 600$ worth. Can cupping cause the vibration, it is still only at 60-65 or should i bring it back to them and have them look at it again?

 

[2001ExpSport]

Getting all that stuff replaced tightened up your suspension so know you'll REALLY feel the imperfections in the tires. Yes, if they are cupped get some new ones. They could also be balanced incorrectly. If inflating your tires helped then it's a good chance you need some new rubber.

 

[Dolphan]

cupping

I have read several posts her on this subject, you might wanna do a search. I also had the famous vibration and believe my front ball joints might need to be replaced. But after I replaced my well worn, cupped, bald - bad tires with new Michelins my vibration went away - FWIW

 

[Sschultz]

Jiimi,
If you got your R/A bushings done ( this is the #1 thing most people on this sight have done, to fight the 60-70mph vibration) some u-joints and wheel bearings done, you got your moneys worth. Go to a good shop to have your new tires mounted and ballanced.

 

[Ryan1]

What are R/A Bushings??

 

[Sschultz]

Originally posted by Ryan1
What are R/A Bushings??

Radious Arm Bushings