Hub concentricity
 

Just read something in Excellence when a reader asked if he should upgrade his boxster's brakes to the big red brake system:

"...before you perform any work on the brakes, you should measure the concentricity of the hubs as you rotate them. I have seen some that are not round and transfer vibration into the steering system."

Hmmm.

1. I am wondering if this is the source of my steering wheel vibration.
2. Any idea how I can measure them to insure they are concentric?

Probably a dial gauge set-up.

i think that advise is total bull****************. you WOULD do it with a dial guage, but i think this is an example of a magazine writer trying to look smarter than he is.

it doesn't matter if the hub is out of round, what matters is whether it's out of BALANCE. you won't be able to tell by measuring runout. additionally, even if it WERE a little bit out of balance, its moment of inertia is very small. it's highly unlikely that this is the source of your vibration.

I'm still chasing down a steering vibration, and as far as the hubs go, have replaced both front complete hub carrier assemblies, and this did not cure the problem. Prior to this, checked runout on both and it was almost zero.

At this point in my case, I've replaced everything up front save for the rack itself, which may wind up being the culprit. I do, however, have to really wonder how even if I did have some slop in the steering rack how that would translate to a speed sensitive vibration.

Patrick