Worn FCABs at 68K. Steering wheel shake. Related?

[RADRACR]

A few weeks ago I had the shop mount and install new tires. They noted that the FCABs are shot. I didn't want to spend the money on that. When I got the vehicle back, I noticed steering wheel shake at highway speed like the tires weren't balanced. So I brought it back and he said one was slightly unbalanced so he did it again to that one wheel. I noticed no difference. They did regular balancing, not road force balancing. Also note that I'm coming from 18" to 20" wheels.

So what's more likely? Are they incompetent at balancing tires or do worn FCABs result in this symptom?

Also, is it true that the whole control arm needs to be replaced to replace the bushings?

[StatenEye]

I'm thinking worn bushings would mask vibrations not create. So the fact that you're getting vibration feedback would lead me to believe your FCAB are not in terrible shape. I would say this is 90% due to a problem with the wheels. Are you sure you don't have light bends in any of the wheels? Repaired Runflats?

[RADRACR]

Wheels and Tires are brand new. Guess I'll go to a different shop that does road force balancing to start...

[goodmaj]

I had a similar problem on my M5. Bought brand new Toyo Proxes 4 Pluses. Had them installed and the drive was just terrible. Then had them road force balanced, this helped slightly but also revealed that one of the tires could not be balanced at all. Sent back that tire and got a replacement. The replacement balanced....but the drive ended up only being marginally better. Ended up replacing the entire set as they were still under the 500 mile no muss no fuss refund period and went with Michelins. No problems after that.

[PAX5]

Originally Posted by RADRACR

A few weeks ago I had the shop mount and install new tires. They noted that the FCABs are shot. I didn't want to spend the money on that. When I got the vehicle back, I noticed steering wheel shake at highway speed like the tires weren't balanced. So I brought it back and he said one was slightly unbalanced so he did it again to that one wheel. I noticed no difference. They did regular balancing, not road force balancing. Also note that I'm coming from 18" to 20" wheels.

So what's more likely? Are they incompetent at balancing tires or do worn FCABs result in this symptom?

Also, is it true that the whole control arm needs to be replaced to replace the bushings?

Around 50K to 70K is typically time to replace FCAB. I did my '08 at 70K mi.

Bushings or complete arm? The choice is yours: $$$ vs labor. But inspect the ball joint that's attached to the arm! May need replacing also. Go with a reputable brand. There are many far east flavors out there ...

To test the FCAB, drive about 5mph and tap the brakes lightly. If you feel a "thunk" in the wheel, you need to replace. You can also inspect visually with a pry bar.

Are your 20" wheels after market or OE? Many people have reported balancing problems with aftermarket wheels. No amount of balancing will get it right. Next time, spin each wheel before you mount a tire on it. Then decide ...

If it's an OE wheel, I would still spin the wheel without tire before making the decision to mount and balance, especially if it is used. Check for wobble and run-out.