Hyundai Repair: Steering wheel vibration, wheel vibration, wheels and tires

Question
I have a 2.o L, 2001 tiburon and it has a nasty steering wheel vibration. You don't seem to feel it throught out the car, just in the steering wheel. It is an off and of problem at city speeds (50-80km/h) but pretty consistant at highway speede (100-120km/h) anyting over 120 it seems to stop vibrating. Now I though it was a steering allignment but I put it in the air and it still vibrated. I have had the wheels balanced and the front rotors and brakes were just replaced. We thought that it might be an axle going but even when one wheel is stopped from moving in the air it vibrates on both sides. I guess this could mean that both axels are shot but I'm not sure having limited experiance with front wheel drives. Any other ideas on what could be causing this problem. Any help would be great!!

Answer
Hi, Stephen.  This sounds like a classic wheel balance issue, but I see you've already balanced them.  I'll presume that when the car was in the air, you were able to feel the vibration inside the car but noone saw what was actually vibrating.  If there was a vibration seen, I'd like to know where this vibration was.  In fact, even if the wheels and tires are well balanced, it's not uncommon to feel a vibration when the vehicle is run at 100-120km/h in the air, so a vibration after stopping one wheel doesn't necessarily mean the problem is elsewhere.  

It's doubtful that you've got two bad axles causing a vibration.  First, that's a rare problem on Hyundai.  Second, it's even less likely that two would be bad.  Axle vibrations tend to be about twice the wheel speed frequency, whereas wheel vibrations tend to be wheel speed frequency.  Alignment issues won't cause a vibration unless there's significant suspension damage.  And rotors would tend to cause a vibration only when braking.

I'd recommend thoroughly checking the wheels and tires.  Put the car back on the lift and spin the front tires.  Make sure there are no bulges in the tires and that the wheels are not bent.  Recheck the wheel balance on a known good balancer.  It's possible if you've used fix-a-flat or similar product that there's liquid inside the tire making it impossible to balance correctly.  I've seen this a few times.