heavy vibration from rear at speed even after wheel balance

kaj2003 · Post by **kaj2003** » 28 May 2009, 19:35

So I'm at a loss now! Just bought this t5-r and after getting the car, it had a bad vibration at speed. I took it to get wheel balanced and rotated. Vibration is less, but still noticeable at around 70mph. Enough to see visible shaking in stuff like the headrests. Guys at the shop didn't mention cupping on the tires. Rims don't look bent (i think).

Mandrake · Post by **Mandrake** » 28 May 2009, 20:47

Sure sounds like a bent wheel. It is not always noticeable when they are bent and even a slight bend will cause a vibration, especially with low profile tires. Also assuming that you have rear disk brakes it possibly could be a badly warped rotor.

Post by **vegasjetskier** » 29 May 2009, 07:57

There was a lady poster on here a while back who had a similar problem. It turned out a bolt had fallen out of a suspension arm. So it might be worth it to take a look at the rear suspension.

waynej · Post by **waynej** » 29 May 2009, 08:16

Of course he has rear disc brakes. The last time Volvo used drum brakes was in the early sixties! I don't think they ever used that insane system where disc and drums get mixed on the same car.
I don't understand how a warped rotor could cause a vibration when he is not applying the brakes. The bent wheel sounds the most likely, but that should have been obvious to the guys in the tire shop when they spun it up on the balance machine, if they had their eyes open.
Jack up the rear of the car and spin the tires by hand and see if there is any side to side movement of the tire. There should be none.
Also try switching front and rear wheels and see if the vibration moves to the front.