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Geometry
Lightning - 24/11/04 at 12:13 PM

I have just had the geometry checked. As detailed below.
The main suprise was that the castor angle was very different one side to the other. Yes I have checked they are the right way around.

They suggested that there should be a toe in on the rear of about 40mins. Any thoughts?

Also input would be of help on the other angles so that I can adjust accordingly.

Road and track possible settings would be also helpful. I appreciate weights and conditions will influence but a starting point would be of help. Rescued attachment Geometry.jpg
Rescued attachment Geometry.jpg


Mark Allanson - 24/11/04 at 07:04 PM

All done on a Hunter system.

I have a similar system at work. The rear end setup does not ever want to have toe out, it would oversteer like a bad one if it did. It all depends what tyres you have and the maximum slip angle you are ever going to generate, low profiles would need less toe in. The harder you drive the car, the more toe in you need.

I used to run my X19 with 10mm of toe in, I used to drive them hard and have 165 70 13 tyres.

It is most important to get your thrust line sorted out so it pull straight.

At the front, always have a little more camber on the left wheel than the right, this will counteract the road camber and give a nicer ride and no pulling to the left.

I think if you set up with a little toe in at the front, and the rear as I have said and RECORD the reults, you can alter it as you want to suit your driving and the car


Lightning - 24/11/04 at 08:12 PM

Mark, you say a little more camber on the nearside front. Do you mean -ve camber?

What about the cambers generally?

I have 195-50-15 Yokos BTW

Also how is the thrust angle calculated



[Edited on 24/11/04 by Lightning]


Mark Allanson - 24/11/04 at 08:25 PM

-ive camber on the nearside, on a dead flat surface, this would give a slight drift to the right. All roads are hump shaped to let the rain run off so cars tend to drift left if you let go of the steering, the slight added camber compensates for it.

The thrust line is easy to calculate, it is 90° to the axle lines (assuming they are parallel - you would be amazed how many are not).

The slip angles cannot be calculated, but 50's will not generate much of an angle so I would start with 5mm and work from there - you do not need to do another geo to set it - just get the Hunter operator to count the turns per mm and you can set from the initial setup.


My car is not quite on the road yet (but it has been) and I have a live axle so all my adjustments will be at the front. I am going to set -20' LH and -10' RH and run 2mm toe in and see how it goes.

[Edited on 24/11/04 by Mark Allanson]


Lightning - 24/11/04 at 09:29 PM

Cheers Mark, I'll let you know how I get on.