Re: Suspension Analysis

[steveb@falcon.kla.com (Steven Buchholz)]

> Jeffrey wrote:
> 
>  "but I soon figured out that big bars on the back of FWD cars are kind 
> of pointless if the inside rear wheel is already lifting off the ground 
> under hard cornering ... and if you drive these cars the way they're 
> meant to be driven, this happens all the time!
> 
> The "purpose" of the rear bar is in the area of "oversteer" and 
> "understeer" Audi's Coupe GT(non turbo non quattro) are notorious for 
> the "PUSH" under hard cornering. Due to the weigth of front end, and 
> "saftey minded" suspension engineering.   
> 
> The rear anti-sway bar actually helps out the front suspension, by 
> keeping the "outside nose" from diving too hard in a corner, and 
> therefore, reducing the inherant oversteer, or "push".  SO, if you leave 
> the bar off, it makes matters worse. Especially for a street driven car, 
> and an "average" driver. 
> 
<SNIP>
> 
> Now, VW GTI's, there at home with the inside rear airborne. A friend of 
> mine would try to stop this wheel from turning, while in corners, just 
> to amaze the audiance!  
> 

... I think Jeff's point is that if the wheel is in the air it probably 
isn't going to be providing a lot of supporting force for ANY other cor-
ner, so the bar isn't of much use.  Notice also that he did specify that 
the car was FWD.  

VW GTIs are not the only cars that are really happy with their inside 
rear wheel airborne ... I used to do the same thing with my '78 Audi 
Fox GTI.  AAMOF, the only time I ever got that car to oversteer was a 
time when I made a quick left-right transition over a set of railroad
tracks that got one of the rear tires off the ground.  I wish I had a 
picture of the look on my passenger's face after that maneuver ... and
he drives enthusiastically as well!  It is always good to have these 
things happen in non-hazardous situations ... even though it was the 
first time the car oversteered I still naturally corrected, and as I 
recall I even set the wheel back down fairly smoothly.  

I used to wonder why the bodies of the cars were so flexible ... Audi
certainly did stiffen things up with the urQ ... I guess raising ANY 
wheel in a turn on a car with open differentials is a bad thing.  

Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)