After 8 years, finally no Shimmy :)

[Asamaan]

I have been a long time reader of the forums, but I rarely post, but I figured I needed to finally share this moment.

I bought my E34 M30 back in 01, and had shimmy from the day I bought it. I replaced the thrust arms and rotors back then but had a slight shimmy that never went away. I replaced the rotors with some Brembo rotors a couple of years back and bought some steel wheels to fix it, but no luck. I finally decided to replace lower control arms, center tie rod, idler arm, and thrust arms again. There were no shimmy except for braking. So I order a set of zimmerman cross drilled and as I was mounting them I noticed by just setting the set screw and rotating the rotor I can still see it shift back and forth in reference to the caliper carrier. I decided to mount them with the lug nuts and spin them and it was straight. I installed the set screw while the lug nuts were on, and it stayed true. Finally I test drove it with my steel wheels to eliminate any possibility of the hub-centric rings causing the shimmy, and for the first time in 8 years, the car has no shimmy under any condition.:D

Cheers,
Al
91 535IA

[mikell]

A long journey, but you arrived. I don't think I'd have been so patient.

[h2oyo]

A long journey, but you arrived. I don't think I'd have been so patient.

Great find, I know if you look long enough, and ask enough questions you will find the answers. Happy motoring.
Johan

[BMWCCA1]

So I order a set of zimmerman cross drilled and as I was mounting them I noticed by just setting the set screw and rotating the rotor I can still see it shift back and forth in reference to the caliper carrier. I decided to mount them with the lug nuts and spin them and it was straight. I installed the set screw while the lug nuts were on, and it stayed true.

Did you try installing the set-screw first then tightening the lug bolts and then checking it? I can't believe the set-screw has enough clout to affect run-out. You don't even need it there.

Regardless, glad it worked out for you!

[Kibokojoe]

So torque the lug nuts without the wheels and tighten the set screw. I will give it a go on my sons 7 series. He has a slight wobble at 55 and we have replaced everything else and still have a wobble. Will let you know

[Asamaan]

I didn't torque them down but snugged them a little more than hand tight, and made sure I tightened them little by little in order to ensure they are on straight in a star pattern, just as if you are installing the wheels.


So torque the lug nuts without the wheels and tighten the set screw. I will give it a go on my sons 7 series. He has a slight wobble at 55 and we have replaced everything else and still have a wobble. Will let you know

[Asamaan]

I didn't try that, but I am thinking you might be better not even putting the set screw. If I put the set the screw and it tilts the rotor slightly even with the lug nuts it won't pull it the last couple of mm unless you break the set screw head or stretch to flatten the rotor.

This is just the way I would imagine it work, I didn't actually try it, so take it with a grain of salt.

Al
91 535iA


Did you try installing the set-screw first then tightening the lug bolts and then checking it? I can't believe the set-screw has enough clout to affect run-out. You don't even need it there.

Regardless, glad it worked out for you!

[genphreak]

Sounds like an interesting approach... if this happens tho, something isn't right in the way the rotor sits. I bet it won't happen with an OEM ATE/BMW rotor. When the shimmy went away, was it always happening under brakes, or only under certain conditions like under brakes+going up or downhill and/or at certain speeds?

Great post/tip- thanks. I'll give it a shot too... not sure what my rotors are yet