Another Drew

I've heard many people complain about the 60/40 weight distribution of the S4, but in a way, isn't it better to have more weight on the front wheels on a quattro to REDUCE corner exit understeer? The front wheels are doing a double duty of turning and accelerating so you want more weight on those tires to increase traction.

I thought I read somewhere where Audi intentionally designed it to have a heavier front end.

LCP

Think about where a tire has the most traction -- it is where it is sliding slightly and when it is under a certain level of weight pressure from above; this is why a light car can be so fast around a track. The excess weight on the front tires negatively impacts the optimum amount of traction available to those tires by overloading them. If the front tires were wider, however, then they wouldn't be overloaded from a weight per area perspective. At the same width as the rears however, the rears have less weight pushing down on the same surface area, allowing them to grip better than the fronts can. I realize this isn't the most poetic explanation, but it's concept is right out of "Going Faster".

Mr Snuggles

Yes and no. Yes, you do want more downward force on the wheels to help increase grip, but you do not want extra weight. Why? Well the extra weight contributes to a greater centripital (I'm sure I've spelled that wrong) force which counteracts the extra lateral grip brought about be the added weight.

This is one reason why aerodynamics matters some much in race cars, and why it is possibile to obtain 1+G's in lateral acceleration ... with proper airflow you get "free" downforce, meaning extra downforce without extra mass.

Anyway, those are my thought on the issue.

Nogaro

But in our case it too much and the weight becames a problem. When the tires are gripping more weight is better, to creat more traction. But once it passes the max traction, more weight means more force is needed to get back into the gripping zone. I think its a matter of taste, some like 50/50, some like heavy front, some want a 911 where all the weight is in the back.

Another Drew

The front gets lighter when you're accelerating while turning, right? For a rwd, the front wheels only have the duty of turning so the rearward weight transfer doesn't hurt the frontend traction as much as a quattro. The point I'm asking/stating is that the S4 will have worse power-on understeer if the weight distribution was 50/50....meaning with the S4 at WOT, the weight distribution may be 40/60 and having 40% of the car's weight over wheels that are pulling and turning is worse.

Of course I know that 50/50 is better for steady-state turning.

Silver S4

If there is more weight is front, then under hard throttle my rears might be receiving more power and there fore being used more. Do I make sense is that hog was?

Warren Wang

Nah, the rears will always wear slower, unless you have an alignment problem.

LCP

...after all, you're really not experiencing much understeer or oversteer at all if your tires are not sliding some, and with a 50/50 setup, the even lighter fronts have more grip (when sliding already) if there's a lighter load on them than they would with the heavier load created by a 60/40 setup. If the tires haven't really started to slide yet, then the heavier load created by a 60/40 setup probably does yield more grip in the same situation, but if the tires aren't sliding yet, what do you need the extra grip for?

KurtW

While the downward force ("anti-lift") is beneficial for traction, if the source of that downforce is strictly the mass-pulled-downward-by-gravity, any benefit is cancelled by the lateral centrifugal forces pulling that mass to the outside of an intended turn, to stay at rest, to maintain its current motion, etc. The ideal would be as little mass impacted by as much downforce as possible, as in an inverted wing - thus we have Aerodynamics.

The lateral loading of the tire, up to its adhesive limits, would likewise be at its most optimal if it were loaded closely to its limit by downforce, and while not having to overcome the force of any mass trying to pull the tire to tangent, i.e. straight.

And this doesn't even take into account the effects contributed by suspension geometry, spring and dampening rates, etc., which act upon our cars in handling performance.

Žob

The engine sits so far forward of the wheels due to the transmission design with quattro. A prime example of what that looks like is here in the below link<ul><li><a href="http://www.tiac.net/users/rdh/http/Urq/">http://www.tiac.net/users/rdh/http/Urq/</a></li></ul>