Hubcentric newb question on thin spacers

[Vincent Brick]

I've never messed with hubcentric stuff before, not aware of ever needing it, hopefully this isn't too dumb of a question.....

I have E21 Alpina wheels on my E30 which require a 3mm spacer in the front to clear the caliper. This spacer has no sort of sized hubcentric ring, and I have realized that my front wheels are only centering themselves from the conical lugs, unlike the rear which very positively locks onto the hub before installing the lugs. I am looking at other 3mm thick 57.1mm hub spacers and they all look the same as what I have. Is the front not supposed to lock onto the hub like the rear does? Do you just have to go without when using such a small spacer? It actually doesn't appear like the wheel would fit on the hub any tighter if the spacer were not there.

I mainly ask because I still have a front end shake at ~75mph even after wheel balancing and all new ball joints/bushings/stc..

Thanks for your input.

[LJ851]

There is a machined portion of the hub that ideally the wheel locates on thus making it hubcentric. Usually the center of the hub area is taller than the actual machined hubcentric area .

For a spacer to be hubcentric, it must be at least a few millimeters taller than the height of the center of the hub so it can neck down to an ID dimension smaller than the center of the hub and create a new hubcentric area.

This usually is around 10-12mm at a minimum. If you run a spacer thinner than that, your wheel can no longer be hubcentric. Certain wheels with a very small center chamfer will still retain hubcentricness with a very small spacer like 3mm.

[Vincent Brick]

That totally makes sense, sounds like "just one of those things." Thank you.