gkmccready

Who wants to take a stab at the effect track width has on handling in Corvettes?

C5 non-Z06: 61.9 / 62.0 = -0.1
C5 Z06: 62.4 / 62.6 = 0.2
C6 non-Z06: 62.1 / 60.7 = 1.4
C6 Z06: 63.5 / 62.5 = 1.0

Add to this that we use camber plates and non-standard wheel sizes and backspacing and you can change track width pretty substantially. Seems to me with the adjusters on the LCAs or with camber plates we all mess with track width, often unintentionally, just in doing an alignment.

How much track width difference front:rear is too much? too little? Why did GM put such a large difference in the C6?

With my car, with aggressive camber plates and CCWs, I'm something close to 1.7in wider track in the front than the rear...

geerookie

It was suggested to me to shoot for at least 1in greater track width in the front than the rear for a track car.
Looks like you got it.
Wider in the front helps turn in.
Wider overall effectively helps lower CG.

spazegun2213

I was under the impression that there was no difference in the c5's widths... So now i ask, 1) where did you get the data, and 2) whats different about the suspensions?

geerookie

Assuming the frame pick up points are the exact same and the UCA and LCA are the exact same, which we know they are. Then if you take into account the 1" width difference and the different offset of the C5 Coupe wheels 63mm and the Z06 wheels 58mm and you have the approx. 1/2" track width increase.

Only difference is wheel offset and width.
Checkout this link:

http://www.corvetteactioncenter.com/...2001specs.html

froggy47

I was having a similar discussion with a solo (2x nat champ - not corvette) driver.

In scca solo (stock) we can add 1/2 inch total track to either end (or both) per rulz.

I thought adding track ADDED grip to the end that you do it to, if you don't do both.

He insisted (and he knows more than me) that it LESSENS grip.

Talking mid corner grip, not turn in or other aspects of handling.

We are talking small amount if 1/2 inch, but I think it could be significant with larger measurements.

waktasz

^^ I don't believe him.

geerookie

Steady-state load transfer is a function of lateral acceleration, track width, CG height, and coefficient of Friction.
We all know that increasing lateral acceleration is Good

trackboss

You really need to use overall width (outside sidewall) for this.

gkmccready

I got that data from good old Google looking at whatever car specs I could find.

meldog21

I just checked my car that has my winter street tires on it (PS2's). Using outside sidewall as the measured distance I got completely different numbers than the 60" range listed in the original post.

C5 Z06 with 18x10.5 rims all around, no spacers, 285 fronts, 295 rears -

75" front
74.5" rear

Is my car completely wacked out or what?

Dog

geerookie

Track Width is measured Hub to Hub.

gkmccready

It's actually wheel centre-line to wheel centre-line. Isn't it?

Gray Ghost GS

That's my understanding. Track width is measured from the center of the tires and can only equal an "hub-to-hub" measurement if the wheels have a 0 offset, which is not the case with our wheels.

geerookie

Now that you mention it, that is correct. I measure from the inside of one wheel to the outside of the other.

Kubs

Thats how I measure. NASA only allows an increase of 3" in track before adding points. I wanted to make sure the spacers and aftermarket wheels I had met the requirements.

gkmccready

Can you elaborate on why?

I'm a bit surprised that people haven't experimented with various track width configurations by way of wheel backspacing and/or spacers.

trackboss

simply because of wheel backspacing and sizing. Install a wider tire/wheel and the overall width will get wider unless the additional width is added to the backspacing. The amount of rubber on the ground and where it is at is what will matter in this case. Also, overall track width is what is measured when there are restrictions in race classes.
I think why mfg specs use track width is because it cannot change by changing wheels/tires. It is a measurement that is used on paper when drawing out the geometry

dmiz0420

Different spring rates can affect ride height by changing the geometry of the upper and lower suspension arms. This in turn could contribute to the change in track width depending on the suspension arm angle.

The c5 and c6 base to z51 to Z06 definately have different spring rates, so stationary they might be different, but when loaded the geometry should flatten out and "grow".

0Randy@DRM

We have always measured wheel track from the outside of the wheel to the inside of the other. This gives us the center of the wheel as a measuring point. We have been aiming for about 1 inch wider on the front for as long as I remember.

Randy