Jim and Alex,
For many years I was told and believed that any out of balance on the rear was
not part of the shimmy because of the large mass of the rear axle assembly.
Then about 2 or so years ago I decided to check out the brake drums. At about
this same time the discussion popped up on the list.
I found that out of balance brake drums at the rear can be a major contributor
to shimmy. After balancing the drums on my BJ8 it made a significant
improvement in the problem! And it took 2-3 ounces welded to the perimeter of
each drum to do it!
I suggest you take a look at that possibility.
Keith Pennell
> Hi Jim,
> Here is a check you can make to possibly help eliminate the shimmy if you
> have tried everything else. Many suffer with the problem even after changing
> everything up front but to no avail. Jack up the car and remove the wheel.
> Ideally you should have a run out gauge, but can run the test with a good
> straight edge. If you are using a run out gauge set it so the indicator
> finger is at the edge of the hub. rotate the wheel and see what the run out
> is. If it is beyond .008" to .012" this will increase significantly at the
> tire edge causing the shimmy. If you are checking with a straight edge,
> place it across the hub and see if you get any rocking end to end. If you
> find there is run out or rocking with your hub, a good machine shop can true
> it in a lathe. I have solved "cowl shake", "shimmy" in many LBC's with the
> problem. My TR6 and TR3 had this problem after complete front end rebuilds
> during their restorations. No problems now. My TR3 was out .018", my TR6 was
> much more severe, .042". Both corrected on my lathe and solved a long
> standing shimmy.
> Alex
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