Another wheel shake thread...with a twist

[E30Gus]

A while back I rotated my tires to find out the now fronts have horrible wheel shake. So i had the fronts rebalanced. One of the rims had flung the weights. All is good.

Last month I go to the track and before leaving i put on my street tires to trek home. Again with horrible wheel shake. I pull over and check tire pressures and everything looks good.
The next day I investigate and could not find anything wrong but this time putting the tires back on there isn't any wheel shake. Now I'm thinking that there is some kind of tire out of round thing going on but can't explain it. But the car isn't complaining so I am not going to mess with it any more.

I ordered new brake pads and put them on a few days ago. Wheel shake is back. WTF?
Yesterday I get home and check tire pressures again and all is good. I take off the fronts one at a time and carefully inspect each tire/brake area and everything looks great.
On the 2nd (Pass) tire I take it off and mark the wheel orientation against the rotor as a ref.
When I put it back on I put the wheel 180 deg off of its original orientation. Wheel shake is gone.

It seems like there is something upsetting the wheels that isn't obvious. And the wheel shake comes in harmonics on the highway. One minute it is smooth, then it starts slowly then vigorously then goes away again. I have 10mm spacers up front but they are hubcentric. I can't think of what else it could be. Any ideas?

[E30Gus]

no ideas huh?

[E30SPDFRK]

The spacers are hubcentric to the wheels and the hubs for sure? It sounds like a wheel centering issue.

[E30Gus]

Yeah that is what it feels like. The spacers are H&R with the correct center bore and both sets of wheel are E30 specific. (TR1s and Team Dynamics)

[bmw325csi]

I had a similar issue. Turned out the shop that balanced my wheels (twice) sucked and did not know what they were doing.

Try getting a balance at a reputable shop.

Also, this might be BS but my cousin has a tire shop and he told me that he likes to silicone the spacers to the wheels when he balance's them.

[E30SPDFRK]

Possibly something inside the tire? Water usually evens itself out over time, but it could be getting stuck in one place and causing a random shake.

How are you torquing down your lug bolts?

[E30Gus]

When I lost my weights I went to a performance chassis place that does road force wheel balancing and everything was smooth leaving there. I torque my bolts with a torque wrench evenly adn I know I am doing it right.
I hadn't thought about water but once the vibration is gone it stays gone so I think SPDFRK is right there has to be a wheel centering issue...probably operator error.
Unfortunately I am not going to remove and replace a wheel a bunch of times to try this out. I could put one on sloppily and see what happens. Maybe try to get it off center a little bit. Thanks for everyones input.
Werd

[Madhatter]

got a dial gauge? pull the wheel off the car and check hub runout against the flange of the rotor with wheel bolts installed and torqued down to make sure it is seated properly. If you have more than a few thou, pull the rotor off and check it directly against the hub. If it is still there, you have bearing problems or the hub is warped.

If the runout is fine at the hub, get out a wire brush and clean all mounting faces and bolts, then assemble and recheck again against the rotor. If you have any runout, mark the rotor at the top, remove the rotor (carefull not to move the hub) and install it 180 degrees opposite. If the measurements are similar top and bottom, the problem is in the rotor, if they are different top and bottom the problem is in the hub.

Replace which ever is the problem.