I am an original owner of a 2004 SR5 V6 with 230K miles. Stock configuration and suspension.

I have been running Cooper AT3's. Cupping pretty bad with about 40K miles on them. Been rotated regularly at 5K. Trucks handles normal and smooth on the road. Just noise from the cupped tires.

I have been planning on replacing the tires in the Spring. Brought the truck into my local Toyota dealer for a suspension inspection. They have serviced the truck since new and have always been honest with no upsell BS. The technician did a test drive, and everything felt normal to him. He then put it on the alignment machine, and everything checked ok within spec. He then racked it up and inspected the suspension. Shocks and struts were fine and no leaks. Only issues he found were the front LCA bushings have "some play" and the right outer/inner tie rod has a "very small amount of play". The technician said those issues could "possibly" causing or contributing to the tire cupping. Both he and the advisor said they did not see any compelling reason to replace the LCA's or the Tie Rods, at least from a safety standpoint. At over $2K to replace those parts, I sure do not want to do it if there is no safety issue, and it is only conjecture to what extent if any these minor issues are contributing to the tire cupping. On the other hand, I do not want to buy a new set of tires only to burn through them prematurely because of tire cupping. It is my goal is to get my 4Runner to 300K or another 5 years whichever comes first. I guess pragmatically speaking, burning through an extra set of tires, will cost a lot less than the cost of replacing those parts. If I knew for sure replacement of those parts would solve the cupping problem, or if there was a safety issue, then I would probably bite the bullet and replace the LCA's and Tie Rods.

Thoughts?