Mitsubishi Repair: Vibration, 99 eclipse gsx, balance problem

Question
Hi i have a 99 eclipse GSX i have a vibration in the steering wheel only at 70mph to 80mph, the wheels were balanced but they are really cupped, and wore, i replaced one tie rod, there were dents in the inside of one rim too.  I'm thinking its just the tires and wheels being bad...i bought the car from an auction knowing that i was going to have some fixers but thats what i wanted but ive done just about all i know...being that its all wheel drive could it be driveline?  Thanks for the help

Answer
Hey Lance: I am pulling this out of my repair manual.. it says that cupping is caused from three different things, underinflation and/or mechanical irregularties such as out-of-balance condiition of wheel and/or tire, and bent or damaged wheel. Loose or worn steering tie-rod or steering idler arm. Loose, damaged or worn front suspension parts. If your tires are already cupped, I would think that would cause that vibration in the steering wheel that your feel at higher speeds. I know I drove a car the other day with a balance problem but that was because it needed to be balanced on all four wheels. Once that was done, the car dives much better and of course they did get four new tires too. Does wonders. So I would check the ideas from my repair manual. And see  what if any of them does for your problems, but new tires or different ones would help too. Don't know where you live but sometimes you can pick up some used tires for cost and that would get those cupped ones off your car. I still think the vibration is the tires, I would get different tires first before I started looking at the drive line. You could have a bent wheel or two too. I also, I say try the easy and not so costly things first and then move on to the other things. Hopes this helps and good luck! Linda