Re: Aftermarket wheel shaking

[Kevin Ford <chery_ford@bc.sympatico.ca>]

Christopher Hlubb wrote:
> 
> Hi guys,
> I have a 98 A4 2.8 Q and just put a set of 17" TSW Evo on. I was
> initially having a
> problem with one of the wheels and found that it was balanced
> incorrectly, that was fixed.
> Now, at about 65 mph I feel a tight shaking coming from the front end of
> the car. I can't
> figure out what's causing it. I have had some Audi enthusiasts check it
> out this weekend at
> a meeting in Washington, D.C. The car is smooth until this speed and is
> at its worse
> between 65-80 mph. I have only taken beyond that once and it seemed to
> die off a little.
> I'm afraid to take it any higher with this shaking. I am hoping that it
> is caused by alignment.
> The car is slightly out of alignment because of the new wheels and that
> is noticed through
> the strong pull to the side when stopping or letting go of the wheel.
> The wheels do have
> the hubcentric rings on them so I'm out of idea's. Please help!

I had a similar problem with aftermarket wheels and tires that used 
the hubcentric rings on my 5ktq (225/50R16), shaking like you 
describe.  It seems the adapted rims are VERY senstive to balance.

To resolve the problem, first I ensured the tires were fully broken-in 
on the rims (about 1000 km of driving), then I balanced them (myself, 
it helps if your tire shop is co-operative!  I also verified the 
balance on another balance machine in the shop).

Then I removed all paint and corrosion on the hub where the concentric 
ring mounts ( I also cleaned the flat mounting flange similarly).  I 
made sure I did not remove any steel.  I carefully mounted the wheel 
on the hub, and hand tightened the wheel bolts.  I then torqued the 
bolts in a star pattern in two steps, first to 40 ft-lbs, then to 80 
ft-lbs.  This procedure finally eliminated the shake the car had.

The concentric rings that came with the rims on my car are plastic.  I 
was actually going to machine aluminum rings and press them into the 
wheels permenantly, but now that the shake has gone, I haven't 
bothered.

The performance type wheels will tend to cause an alignment problem to 
be more apparent, but the pull you describe sounds like something is 
majorly wrong.  A car this new shouldn't be having problems like this 
without some cause (impact).  Time to see if the alignment is in spec.

Note some alignment computers have different specs for Audis compared 
to what Bentley states.  I like to follow Bentley.

Kevin Ford