Mike Andrews

Rick,

I wanted to add a little to Chris' post.

When you corner balance a car you are adjusting the preload on each of the tires. You can not move weight from side to side or front to back (or back to front) by corner balancing your car. Using the example above (in a perfect world) if the car weighs 3,000 pounds then 1,800 pounds are on the rear and 1,200 pounds are on the front with 1500 on each side. Or 600 per front and 900 per rear. In reality you'll have slightly more weight on one side so those numbers won't be obtainable. What you will look for is a 50 - 50 diagonal weight distribution. In other words the left front and right rear will carry the same amount of weight as the right front and left rear.

Remember back to one of the principles of not being able to change the weight of the side, front or back of the car. So, if you change the preload on one of the tires (by changing the preload on the spring) you will change the weight on all four wheels. Taking weight out of the left rear will remove weight from the right front and ad weight to the other two corners. Think about a four legged bar stool. If you take those little beer coasters and put them under one of the legs you will start a process that increases the weight on the one with the coaster and the one diagonal to it. If you continue to place coasters under that leg you will get to the point where only those two legs touch the ground and as you move around the stool will rock from one side to the other. That's an extreme but the same thing applies to your car. If those cross weights are equal the car will be more stable.

And yes, you should be seated in your car. Don't forget the gas. If you are looking to optimize the track performance then you should set up your car the way it hits the track.

And to your question, you should not need to redo the corner balance after the alignment.


Regards,
Michael

911XTC

Love the bar stool/beer coaster analogy. Too true

rickw51

Again, thanks for all of the input. This has cleared things up for me. Now onto the slippery slope ....

CP

Great thread and excellent info. A few more points I did not see covered. Don't corner-balance with an empty tank. At least half-full (assuming you track with 1/2 tank). I did mine with full tank.

The object of a corner balance is to spread the weights equally on all 4 wheels with the car in a loaded condition (driver, or with passenger, and fuel). As 911 has a built-in rear weight bias, one rarely gets equal weights on all four wheels (my M5 achieved almost equal weight all-around). The next objective is that the sum of the wheel weights, across, or diagonal, be as balanced as possible. This gives best cornering performance. Thus corner balancing is done with the car sitting on 4 scales, one per tire.

I believe you can only corner-balance when the shocks can go up-down. Shim is one way (a painful way), but the coil-over system is the ticket, as it is designed to be height-adjustible.

I'm no expert in this area, just seen two of my cars done after coil-over systems were installed. Hope this helps.

CP