Geometry set Up

[mark030358]

Hi all,
I just read a thread (minutes ago) where someone asked for copies of pages from the +2 pages manual, these being for the rear suspension.

This got me to thinking about weight, which I will come to in a moment. When I had my geometry set up on my two seater Elan. I sat in the car with some fuel (can't remember how much) and no passenger. The ride height was set to give a certain camber for the front and rear suspensions and the ride height just ended up where ever it ended up after adjustment. I did have adjustable perches to facilitate this. Also the front and rear tracks were also set and the car was super stable afterards.

Now what got me thinking is that the Elan manual says load the car up along the centre line until the heights at various parts of the chassis are at a certain height, but this is for non adjustable perches and gives no weight.

So, what weights should actually be used to ballast the car and placed where, for adjustable and non adjustable suspension as I can find no reference?

cheers
Mark

[Andy8421]

Mark,

I think there are a few things going on in your question.

1. Setting the suspension geometry to the original factory settings. Some of the parameters are ride-height dependent, so the manual specifies the ride height required for setting. This can be done with the body off (the easiest) with the springs removed and the chassis (frame) resting on correctly sized blocks to achieve the correct height. Alternatively, a fully built car can be loaded so that the chassis sits down on to correctly sized blocks to achieve the correct ride height. The amount of weight required to do this, and where it is placed is irrelevant as long as the chassis is down on the blocks.

2. Setting up a car with adjustable height springs. After step 1 above is done, adjustable springs are usually set to achieve a combination of target ride height and appropriate corner loading. For a competition car, the car would be loaded with oil, water, battery, half a tank of fuel and a weight to represent the driver in the driver's seat. The target ride height after adjustment may be very different to the height used in 1.

[mark030358]

Thanks Andy…