A1 ride height vs. geometry

C

ChrisS

New member
In the forum I have heard quite a few opinions on ride heights. Is there a "proper" starting point? I have heard that you should start with the ball joint and control arm pivots level? It looks like things get weird when the control arm goes less than horizontal- Is this a problem? I assume if it didn't mess with the geometry, everyone would be at the 5" min just to get the CG down.
Thanks, Chris

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When we were running the rabbit we followed Dick Shine's advice and kept the Control Arm level. We also followed his advice on Springs and the car handled great!

Jack
 
Casual observation would suggest that some of the best handling IT Rabbits in the country run a kind of goofy looking, nose high attitude on the track. If you wanted to make one LOOK fast, it sure wouldn't end up the way they seem to...

Kirk
 
Level control arms is probably a good starting point. You can angle the control arms upwards maybe 1/2" - 5/8" (inside to outside), but not much more than that. The front roll center is approx. at the intersection of lines drawn through the attachment points of the control arms. If you lower the car too much (and have the control arms inclined), the front roll center goes under ground. Not to mention that you also kick the angles up on the tie rods, which sends bump-steer through the roof.

As Kirk said, the fast A1 VW's run the rear ride height slightly lower than the front (1/2"). It helps w/ weight transfer under braking, but doesn't hurt acceleration as there's already ~60% of the weight at the front.

HTH.



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MARRS #25 ITB Rabbit GTI
 
Bill, so what corner weights do you use?

We ended up with LF of 665, RF of 668, LR of 436, and RR of 409. This was with 130 lbs of ballast, and a total weight of 2180, and about 3 gallons in the cell. GP Rabbit GTI is 2165lbs. This was a 50.6% cross weight ratio.




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Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002
 
Originally posted by racer_tim:
We ended up with LF of 665, RF of 668, LR of 436, and RR of 409. This was with 130 lbs of ballast, and a total weight of 2180, and about 3 gallons in the cell. GP Rabbit GTI is 2165lbs. This was a 50.6% cross weight ratio.
Click to expand...

Can you give us an idea what spring rates you used?

So, it's safe to say that after you're all balanced up, w/ ballast and w/ driver, the LCAs are still level?

To get all of this to happen, do different spring rates need to be used on the Left and Right fronts (or rears) to balance out the weight of the driver? Is it possible to 'play' enough with the coilovers at every corner to make this happen, w/out using different springs rates on the left and right?

I'd like to get my Rabbit corner-balanced *after* the cage is in, and I want to get a grasp on the whole situation before I jump in and do it.

Thanks,
PJ



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83 Rabbit GTI - future ITB
 
Originally posted by machschnell:
Can you give us an idea what spring rates you used?

I think that I'm using 600 lbs up front, and 500 lbs in the rear. I'll have to go out the the shop when I get home and verify.

So, it's safe to say that after you're all balanced up, w/ ballast and w/ driver, the LCAs are still level?

I haven't checked, with me in the car. But the weights were done with me and 130lbs of balast in the Right Rear foot well.

To get all of this to happen, do different spring rates need to be used on the Left and Right fronts (or rears) to balance out the weight of the driver?

I'd use the coil overs for this, not the spring rates. It's VERY easy to adjust the coilovers while your weighing up the car.

Yes, wait until the car is done, with everything that you want on the car, in it's correct location. Heck, even with starting out with the tires @ their cold pressures, as soon as we put them to where they should've been hot, the weights were different, as much as 10 lbs per corner.



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Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002
Click to expand...
 
Tim,

I'll have to check the notebook on what we got the car to the last time we weighed it. Your numbers 'sound' pretty close from what I remember. I got X-weight to between 50.5 and 51 percent as I recall.

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MARRS #25 ITB Rabbit GTI
 
Just checked, and I'm running 500 lbs in the front and 300 lbs in the rear.



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Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002
 
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