Re: 16" Rims on 4kq's

[AUDIDUDI@delphi.com]

> Another example is the Touring Car classes around the world.  If wider
> and taller tires are a bad thing, then why do they run 19" diameter
> wheels with extra wide tires and rubber band side walls.

Two reasons immediately come to my mind: 1) So there is enough room to fit
larger brake rotors and 2) So the tires will last longer.

In order to fit a 380mm rotor inside a wheel, the diameter (obviously) has
to be somewhat larger than that; allow a bit for the drop center necessary
for mounting tires, and you end up with a 19" diameter rim by default.

As for decreasing tire wear, the larger the diameter of the tire, the more
rubber there is and the less often any given point on the tread comes into
contact with the road.  With Supertouring cars being limited to 6 tires at
each event, including practice, making them last is important...

> These cars run essentially the stock suspension design.  If switching to
> a larger and wider tire is a bad thing, then WHY do road racing classes do
> it??

Supertouring cars are permitted to move the suspension pickup points up to
20mm from the OEM location and you'd be surprised how much this can change
things...

Also, in the case of the 4kq, the negative scrub radius is 14mm ... change
your wheel offset by more than this (everything else being equal!) and you
will definitely notice a change in the car's handling, especially on slick
and/or wet surfaces where one wheel or the other is always losing traction
... btdt and it wasn't much fun to drive.  On the track, however...

> I've been around all kinds of racing long enough to know how these
> changes affect the handling of a car, and how changing something as
> relatively simple, such as the tire size or compound, may in some cases
> require retuning the suspension.  Just so it is clear, changing the
> suspension setup on a car, is NOT a bad thing.  You're looking to
> improve the car, and if you have to deviate from the stock settings, the
> world is not going to come to an end, regardless of what Audi originally
> engineered the car to do.

I agree ... I also find it a constant source of amusement to see STOCK cars
-- especially Mustangs and Camaros -- beat modified ones at Solo II events.
If you don't know what you're doing, you can spend LOTS of money and end up
going slower as a result ... btdt, too, I'm afraid.  :^(

     _             _             
    / l       l o l  \       l o   Jeffrey Goggin
   /__l l l / l l l  l l l / l l   AudiDudi@delphi.com
  /   l l_l \_l l l__/ l_l \_l l   http://people.delphi.com/AudiDudi