This weekend during the 5th 20 min session I developed a vibration at high speed, >~115. I thought maybe I'd thrown a wheel weight but they all looked fine. The vibration got worse as the day progressed.

Then I started to get a grinding sound in left hand turns only.

I'm thinking it's the left rear wheel bearing. The only reason I'm posting is that the wheel has zero free play, sounds normal with an automotive stethoscope, and I can't recreate the issue on the street.

I don't want to replace the wheel bearing only to show up at my next track day and have to abort the weekend after only the first session if the problem recurs. Thoughts?

I'm guessing it's the rear because i replaced the front bearing a month ago.

 

I've had the left front, left rear and right rear bearings go on me (I replaced the right front before it went bad). Only the left front caused any vibration and that was because it was so far gone I had about 1/4 inch of movement at the wheel. The two rear bearings sounded like I was dragging a tree branch under the car. At first the noise only occurred in turns (right turns for bad right left side bearing) but later it became almost constant but even then there was no discernible slop at the wheel.

I would think if you're getting vibration your bearings should be making a lot of noise so you may not have a bearing problem.

If you do replace it here's the how-to: http://robrobinette....2000Bearing.htm

 

Rob

Interesting that bad right sided bearings made noise in right hand turns. I would've thought the bearings would've made noise with increased load i.e. right side bearings symptomatic in left hand turns.

I need to investigate a bit further.

Thanks for the how-to, I used it previously when I replaced my front bearings.

 

Oops, you're right. Right bearing made noise in left turns and vice-versa.

 

It happened to me 2 weeks ago.

Lift the car and try to move the wheel. If it has some play that that's what it is.

I did not have "warning vibrations" though, only the sound as if I ran out of brake pads.

 

But that's the problem, the wheels are tight. I'll look at it again today, but so far everything checks out ok in the garage and on the street.

My suspicion is that the bearing is just beginning to go, so under the higher loads and heat of the track it was noisy, but it functions normally on the street.

These problems that can only be recreated on track are a real PITA.

It may be that I did throw a wheel weight and the vibration is unrelated.

 

It's a good idea to cover your interior wheel weights with aluminum tape to help keep them in place.