Cal Club Autocross Forums

... does the Left Front typically ends up being a bit higher then the Right Front ... with the Right Rear being a bit low ... compared to the Left Rear?

... or, since >>>"Lowering" a corner in isolation actually reduces the weight on it<<< ... should the Left Front be lower since one is going to be adding the drivers weight on top of it?

lowering one corner will transfer weight to the corresponding corner. So lower LF will result in higher RR weight. *I think * its been a while and i actually need to do this again soon as ive changed the car quite a bit over the winter.

Your driver (or equivalent ballast) should be sitting in the car when the weight is set.

... of course ... but typically, how does the LF ride height end up as compared to the RF ... lower or higher?

A car that is properly corner balanced should be flat with the drivers weight in the car. Before setting the corner weights the car should be leveled and set at the ride height you want. Then raise one diagonal and lower the other to change the cross weights. Of course taking the drivers weight out of the car will effect the ride height somewhat.

Unless you can balast, there's no way you can get the same weight @ each corner; cross-weights? Absolutely - to the pound.
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Mako - are you asking about your Miata or 'Vette? If Miata, then yes, left front will be heavy and right rear will be light. No idea about 'Vettes.

Adam has it right. Adjust the car ballasted for driver. When the driver steps out, the left side may raise a tad in height. But matching diagonals works best with cars that are symmetrical, like formula cars, or which require enough ballast to make minimum weight such that both sides weigh the same. For most of you this isn't the case.

After you take your four weights, sum the front two, and divide that by total weight to get an overall front percentage. Then sum the two left side weights to get total left side, and multiply that by the overall front percentage. IE, if the front of the car is 55% of the total weight, set the springs so that the left front is 55% of the total left-side weight. Theoretically once you get one corner perfect, all the others will be as well. But life's a compromise, and you do have to mess around a little to get an overall good result. I generally get within 5-lbs of target at each corner and call it good.

I'm not cornering balancing! I was asking a general question

Mako, the answer will be different for every car. You might also be surprised in how a driver's weight is distributed amongst the four corners.

Thanks ... I found what I was looking for in various internet threads/DIY's.

So many experts out there! "To lower the front, turn clockwise" ... others say counter clockwise!!!

Mako Koiwai wrote:Thanks ... I found what I was looking for in various internet threads/DIY's.

So many experts out there! "To lower the front, turn clockwise" ... others say counter clockwise!!!

While you are in the process of undoing all of Brian's work... If you take all the load off the springs with a jack you will be able to turn the bolts by hand. If you don't do this you can ruin the bolts.

Just on a random tangent if any of you have iPhones or iPod Touches there is a Crossweight app that will tally up all the various dimensions for you. It can also store multiple profiles.

http://itunes.apple.com/us/app/cross-we ... 18962?mt=8" onclick="window.open(this.href);return false;

Seems they also make a gear ratio app.

WHOA! Found a PAX App!! You can use it to determine the appropriate time based on index for your class. Sweet!



http://itunes.apple.com/us/app/ipax/id308843678?mt=8" onclick="window.open(this.href);return false;

Thanks ... yes I always jack up the springs so I can hand turn them ... lots of experience on Henry's Vette. The ride heights were really all over the place. Not sure where that came from. I had resisted measuring ride heights from the rails or suspension points in the past ... but today I learned of an easy way to take those measurements ... using part of a turn buckle ... and then measuring it with a micrometer! Duh!

I'm not all that good of a driver, so understand that a lot of my enjoyment comes from tinkering with our cars.

Mako Koiwai wrote: The ride heights were really all over the place. Not sure where that came from.

Did you unhook the swaybars? If not, your numbers would be way off.

My understanding is that if left and right ride heights are the same the bar shouldn't be pre-loaded. Again ... I'm not corner balancing ... yet.

Mako Koiwai wrote:My understanding is that if left and right ride heights are the same the bar shouldn't be pre-loaded. Again ... I'm not corner balancing ... yet.

The weights are typically no good if the bar is hooked up. Unless you are at stock ride height I doubt the bars have zero load on them.

Jason Isley BS RX8 wrote: The weights are typically no good if the bar is hooked up. Unless you are at stock ride height I doubt the bars have zero load on them.

well if you have adjustable end links then you are correct. but you sure as hell want the car corner balanced in the condition it will race in.

Front bar does have adjustable endlinks.

I might have found the problem ... the front spring is offset. Need to re-check it. If it's a 1/4 inch off I'm going to fix it, if it's "only" 1/8th in I might leave it.

If you don't own a setup plate, and if your garage floor is decent (no potholes) is it ok to take the ride height measurements frame to floor? Just the ride height, not all the other setup adjustments.

I usually use a tape measure, case on the floor & extend the tape up to the frame. Good to about 1/32 with a decent tape.

Mako Koiwai wrote:Thanks ... yes I always jack up the springs so I can hand turn them ... lots of experience on Henry's Vette. The ride heights were really all over the place. Not sure where that came from. I had resisted measuring ride heights from the rails or suspension points in the past ... but today I learned of an easy way to take those measurements ... using part of a turn buckle ... and then measuring it with a micrometer! Duh!

I'm not all that good of a driver, so understand that a lot of my enjoyment comes from tinkering with our cars.

If you're measuring that with a micrometer, wouldn't you also want to make sure it's plumb?

Dead plumb would be great, but it's not deal breaker. Even if the turnbuckle is off by 5 degrees the error would be relatively small. You'd just be measuring the long side of the triangle instead of the side adjacent. I'd guess that by eyeball the off angle wouldn't be more than 2-3 degrees. If you wish to be accurate within thousandths, then yes, accurate right angles are necessary. Even then the subjective feel of the turn buckle, combined the the subjective feel of what you use to measure with, can be inaccurate when thousandths are involved. Shouldn't be an issue if your ok with +/- 1/32 inch (.031).

tiny digital "plumb"

http://ecx.images-amazon.com/images/I/5 ... AA280_.jpg

I like to take measurements from things that don't move or have dips. Like bottom or top wheel lip to the fender.

If you measure to a fender you're taking measurement of the body not the chassis. Vette bodies are notorious for being off. Especially noticeable on Henry's Z06 with his ASP wheels/tires sticking past the body work. On one side they stick a 1/4 inch further out from the fenders then the other side. Our C5 body is also off set somewhat, just not as noticeable since the wheels/tires don't stick out past the fenders.