derbyboy25

ok guys i have a 90 4x4 that is wearing the front left tire weird. it wears it on the inside and 'cups' the tire in about 10k miles. with the naked eye it looks like its not cocked in but the front springs are sagged over time it has who knows how many miles on the truck (odometer hasnt worked for about ten years) i have jacked it up and with a bar under tire checked for play and slop with no excessive play seen. i first thought it was the wheel bearing being loose tore it apart and tightened it but wasnt really loose. i am now guessing the kingpins are getting worn out and letting the tire wear bad. i guess my main question is in you guys opinion do i just put a repair kit in it that consists of a new top bushing and seal or will it need a whole kingpin set? How hard is it to do this? this is my main truck right now so i cant be down for days but at the same time she is old and very tired so i dont wanna put a lot in her. thanks guys

j_martin

If toe-in adjustment is off a small amount toward out, it'll wear like that. Proper diagnostics is the fastest and least expensive path to a repair. Throwing parts at it is usually the slowest and most expensive.

I use a very good tire and alignment shop, and for under $100 it gets put right on the money. If it needs parts, either the shop will put them in (Moog only) or I can make the repair and bring it back. No charge for the assessment. These guys are good. They will have checked everything possible for wear in under 10 minutes, including the time to put the truck on the rack.

It quickly sets all my options before me for evaluation. It ranges all the way from have em fix it and align it, to run used rubber on it, to scrap the machine and start over.

To be fair, I've bought all my tires at that shop for about 30 years.

maybe368

Do you have any wobble? There are a few things that it can be, but a possibility is bad king pins or king pin bushings. The setup is so strong that the old pry bar may not find the problem, See here. Good luck...Mark

maybe368

Another thought, many times bad shocks cause cupping of a tire, from the tire being "dribbled" like a basketball on the road by the suspension...Mark

Rick 12v CTD

Mark, I'll second the inside of the tire cupping as a possible worn king pin/bushing. My truck did the same thing.