My stock Goodyear tires on my 2000 Lariat 4x4 have developed cups. So they "thump thump thump" down the road. i've rotated them twice same problem. do i need to replace them..is this hard on the linkage?

 

Balance them (again); and each time you rotate, move them front-to-rear (as opposed to Xing) so you reverse the torque wear on the tires.

 

I have the same problem with a set of new Goodyear AT/S tires I put in my truck last summer. I rotated fron to rear and now the front tires are cupping again. I have been told by a mechanic friend that the tires were probably out of balance when they were mounted originally and I should have the tires warrantied out and replaced. He also mentioned that on 4x4 trucks there are shims that can be used on the front to correct the problem. I'll be having Kaufman tire replace the tires and fix whatever the cause as they are the ones that replaced the shocks and brakes in addition to selling and mounting/balancing the tires from the beginning.