Diagnosing a bent Fuchs problem - answer found
 

My steering wheel vibrates and has a side-to-side wobble. These things are more noticeable at speeds of ~70+ mph.

The wheels were re-balanced to 0.00 on the balance machine. No real improvement.

The wheel bearings appear to be nice and snug, with no play evident.

One front wheel has some curb rash. This came with the car, and no other wheel shows any such damage.

Therefore, I set up this sophisticated measuring device :p using a special camera tripod and a piece of chalk taped to it.

http://forums.pelicanparts.com/uploa...1349029770.jpg

Rotating the wheel indicates a gap between the chalk and the wheel at the point where the curb damage exists, but the chalk squeals against wheel the rest of the way around.

Here's the gap. It is about 2mm. I don't have a dial gauge to measure exactly.

http://forums.pelicanparts.com/uploa...1349030062.jpg

So, my question is, is a 2mm sideways bend in the wheel enough to cause a very noticeable wobble in the steering wheel? This wheel is the only one where I found such a flaw. Where else should I look?

How old are your tires ? If they are not too old, I would try to get a road force balance on a Hunter road force balancer before I did anything else. It is possible that your wheel is part of the problem. Start with the simple things first.

Thanks for the idea. I'd have to hunt for a Hunter. The tires are 3 years old and seem to be round.

During a recent CB and alignment, my tech reminded me of the very slight bend in one of the reare FUCHS that will need repair. he states that the repair process will involve heat...

Inanycase,...he stated (in my situation) it wouldn't matter, as to balance (he jokingly stated that he can balance a square, if necc'y).

Best!

Doyle

That's true. It would be easy to balance a square. Are you saying that a bent wheel can be balanced, but still cause a problem, i.e. vibration in the steering wheel? My right front wheel wobbles sideways as a result of curb rash, but is in balance.

There is a shop near here that seems to do a nice job of repairing aluminum wheels. What should I ask about with this?

Sounds like you might have a warped brake rotor? I did with similar sypmtoms.

David

Would I feel a warped brake rotor in the brake pedal? The brakes feel smooth when operated.

out of balance is the most likely scenario. even if they were done before, there's no guarantee they were done right.

I took the wheel and tire to a shop that does first-rate wheel repair and straightening.

Yes, I was right, the wheel is bent - about 1.5mm. This is not enough to bother about.

The tire, however, could be seen wobbling back and forth, side-to-side, about 5mm. This is enough to cause vibration and shake in the steering wheel. The tire, after all, is a bigger diameter and heavier 'flywheel' than the lighter, smaller wheel, so its affect on what is felt in the steering wheel is greater.

I'm going tire shopping. Unless there is a way to straighten a tire.

+1
Every time I have bought new tires in the past 5 years I have had vibration issues. (four sets, three different cars, three different stores)
I fixed it every time with my home made bubble balancer.
I am not sure why those spin balancers all the tire shops use can be so bad.

That being said in your case I would suspect the tire is out of round.

How much weight do you have on the wheel to achieve a "perfect" balance? I have to use almost an ounce, which tells us that I need to have my wheel straightened. Are you using that much weight?

No, a lot more than an ounce. Like 4+.

Yep. You and I will both be sending out our wheels for repair this winter. We have a great place in Bath, Pennsylvania. I am sure you have a decent place as well up in the Quebec area.

Best of luck.

Nice car, by the way.