[s-cars] Problem vibration in the front end?

[colin cohen]

No sign of an alignment problem with no sign of tire scuffing.  I had 
thought about caster but the it would have to be excessive for vibration and 
would be evident throughout the speed range.

Its not an instability or dartiness caused by toe out.  Plain and simple 
wheel oscillation as one would find with a major wheel imbalance.  But its 
not that as the wheels have been swapped and changed.

The Sq is really an Urq that took an incomplete dose of steroids.  Audi had 
to build them this way to meet Piech's budget constraints: the road cars had 
to pay for the rally ones.

Colin
----- Original Message ----- 
From: "Paul Gailus" <gailus at mindspring.com>
To: "colin cohen" <ccohen5 at compuserve.com>
Sent: Tuesday, November 02, 2010 6:58 PM
Subject: Re: [s-cars] Problem vibration in the front end?


> Colin,
>
> Have you had the alignment checked and/or adjusted recently?  If the 
> alignment numbers have  shifted it could provide some clues about what 
> suspension parts are involved.
>
> This is somewhat obvious, but insufficient toe-in or caster could cause 
> instability.
> Usually you don't need much static toe-in if the front wheels are driven 
> (because the wheels are pulled forward).
>
> I'm not very familiar with the SQ (I wish I was!), so I don't know if the 
> caster is adjustable.
>
> Paul
> 93 S4
> 95 S6
>
> -----Original Message-----
>>From: colin cohen <ccohen5 at compuserve.com>
>>Sent: Nov 2, 2010 11:58 AM
>>To: s car <s-car-list at audifans.com>, urq at audifans.com
>>Subject: [s-cars] Problem vibration in the front end?
>>
>>I am experiencing an odd but very pronounced front end vibration with my 
>>SQ and wonder if anyone has experienced the same thing with an Urq?
>>
>>It starts at about 60/65 and gets progressively worse with lots of 
>>wheel-shake up to about 80 and then reduces somewhat but does not 
>>disappear;
>>
>>Almost undetectable when I drop below 55/55.
>>
>>Here is what I have eliminated: swapped wheels and tires - completely 
>>different sets; new shocks and upper strut bearings (same as Urq); checked 
>>for tie rod integrity which seem tight with no play; and checked for 
>>bearing play.  There is a slight oscillation when braking as if the rotors 
>>were warped but no run out when tested on the car.
>>
>>Any input gratefully accepted.
>>
>>Colin
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>