Front suspension design has been complicated by the 4×4 running gear.
It quickly became obvious that it would be impossible to use the ubiquitous Ford Mk2 Escort steering rack as it would try to pass straight through the Sierra Front diff.
The push rod for the coil-over shock also tried to occupy the same air as the outer c.v. joint.
The rear suspension is complicated by the fact the drive-shafts are different lengths and the c.v. joints have much less ‘play’ in them. Basically, they can only grow a few mm in length as the wheel travels up and down. From a handling point of view, both sides need the A-arms to be symmetrical, but this means each sides drive-shafts will grow and shrink unequally with wheel travel.
Despite the obstacles, after going back and forth between Kangaloosh and AutoCad several hundred times, I think I am there!
Well, almost! There are still a whole load of brackets to draw up, but that’s the easy bit and I will feel happier if I can plot the rising spring rate. I need to work out the pre-load / shock compression – I might need to tweak the push rod bell cranks on the cantilever shock arrangement. etc etc etc
What I have done with the A-arms, is to use a bunch of 5/8″ Clevis joints. These enable loads of adjustment of practically all suspension parameters.
For parts, check out this site :
For the suspension parameters I used, see this page:
If you haven’t seen Kangaloosh or SuspEdit – check them out now! They aren’t just toys used by the gaming community to model cars, they are highly sophisticated pieces of software. Real race teams use this software to model their cars. They can see how certain suspension set-ups perform on various race tracks.
When you download Kangaloosh, you get a set of sample cars. They are all various Caterhams! I’ve used these as a base point for my modelling. This set-up is obviously different, but the figures are ‘in theory’ quite similar and in places marginally better.
Half Track Variation (Scrub)
Roll Centre Migration
Multi-link Steer Caster
Multi-link Steer Scrub Radius
Multi-link Steer Contact Patch Trail
Multi-link Steer KPI / SAI