trackjunky

Don't forget to set basic ride height first. Determine rake desired and ride height. This will allow you to make small adjustments when on the scales.

Also, measure tire circumfernce. This can lead to an unbalanced stool, to continue an analogy. If your tires are worn, you can adjust to what you think is an accurate corner weight, then, when you get your next set of tires the corners are off. Ask me why I know this.

911pcars

After doing the necessary research on the subject, here's a paper-based worksheet to calculate the target weights for each corner.

http://members.rennlist.org/911pcars/cornerbalance.htm

There are also links on this page for an Excel spreadsheet to automatically perform the calcs.

Most street-based cars aren't symmetrical side-to-side like a purpose built race car. Thus the side-to-side weight proportions will be different. Because of this, the diagonal weights may not match (although they can be close), even though the car is balanced.

Sherwood

DAR951

From watching too much NASCAR??? There it's called "stagger".

Larry Herman

No, stagger is when you beat on the car for 6 hours after work, consume way too much beer and have to get from the garage back to the house.

Veloce Raptor

Consider a laxative.

smlporsche

Bill-
Those are two things we're going to do. I was able to coax the basic ride height settings out of Karl Poetl as he set up his class winning S2 so we'll start from there. I spent last year anywhere between a half an inch and a full inch higher than some of the guys I run with and with the steel control arms I should be able to drop the ride height with minimal consequences.

I also decided to put new shaved tires on as I think I had heat cycled out the previous set.

Thanks.

smlporsche

It must be Friday !!

smlporsche

Chris-
Thanks for the link I forgot about setting the shocks to full soft.

Noel

Yes, you are correct, there are definitely more variables to consider with a car.

DAR951

Yeah.. like I said... NASCAR...

RedlineMan

Hmmm...

Another thing to remember here is that a lot of this stuff matters in the extreme, but not in reality, depending on the car. As the spring rate approaches a higher percentage of the car's weight (open wheelers), details like air pressure and shock settings become much more important. For a relatively stock car with lower rate springs, this stuff only stand to add to your workload, not necessarily the success of your outcome.

In other words, most of the cars we are driving do not change noiticeably when all the minutiae is factored in. No, it doesn't hurt, but it's easy to lose the forest.

APKhaos

+1 on that. You need to fully relax the suspension every time you put the car back on the scale pads. Take soem real care with this to avioid wasting time achieving numbers that look good on the scale but are nothing like reality.

fatbillybob

Tires and wheels are symetrical left to right and within maybe an ounce or so of each other. So since most live in the tintop world is there a way to make corner weighting easier? For example does anyone make a post or jackstand that connects to the hubs so that if you have a lift or are really careful with jacks you can weight and unweight the suspension by lifting the car up and down in one place to quickly adjust coilovers? We need something that not only attaches to the hub but slides perpendicular to the long axis of the car to remove stiction in the suspension like jackstands bolted to hubs riding on slip plates.

Van

This isn't exactly true... You want the diagonal loading to be proportional to the front-rear AND left-right weight bias so the car isn't seesawing across the diagonals.

In a car that already has an EXACT 50% balance either left to right OR front to rear, then the diagonal weights would be the same. But, due to the asymetry of things like where the driver sits, this is rarely the case. If your 911 is heavier in the rear, and heavier on the left side, the corner balancing has to involve a simple mathematical equation to make sure the diagonal loading is proper so the car doesn't "seesaw".