Steering setup help please

[db]

My tyres are scrubbing like hell and it has way too much neg camber.

When I can I'll get it professionally set up, but for now i just need it somewhere near...

So unless someone offers a better idea...
I'll shorten the lower front arms until i have approx 1 degree neg camber.
I'll then shorten the track rods until the wheels are parallel.
I'll measure the rake first and keep that as it is.

[Dart Vader]

Blimey, I wouldnt know where to start.....

[Dave-R]

Half a degree neg camber would be enough for that car.

[db]

Thanks Dave.
And the wheels dead parallel?
Any thoughts on the rake?

Is there any precedence on any car ever for having different length bottom arms?
Is it some clever old drag racing trick? It looks very wrong to my uninitiated eye, but it does look intentional

[Dave-R]

You mean they are different sizes on one side of the car to the other??? I hope not.

By "rake" do you actually mean caster angle?

[Dave-R]

Oh and you will need a little toe "in" to keep it straight on the road.

But if the suspension dimensions are different on one side of teh car to the other then something is seriously wrong. It is either a shoddy job or it is making up for a chassis that is not straight?

[Steve]

Way beyond my knowledge base but I know that my local independent tyre fitters have a laser machine that they use to check tracking etc etc. Its the dogs so maybe a quick visit to somewhere with one of these machines would at least tell you whats wrong so you would know what to start with. Think they charge about a tenner or so to check

[Dave81]

Are they scrubbing in a straight line (i take it thats what you mean), or on full/partial steering lock?

[Pete]

You need as much positive caster as possible (Like motorcycle forks). Race cars run around 6 degrees.
Dave is right on the toe in.

As that is a race set up I do not know how adjustable (range) it is.....at the least I would expect to be both sides to be very close to eachother.............

[db]

It's very odd... If you can make out the measurements on the drawing, it's not just a couple of mm error, it's up to 66mm off

The chassis is all straight. I took lots of measurements when i did the 4-link & rear axle, and again when i moved the steering rack back a bit- that's when i discovered the odd A-arms.

That said, the castor/ camber/ wheelbase/ etc are all equal! Go figure

A 'little' toe-in.. My method will be to measure between the inner faces of opposite wheel rims (or maybe the discs) are we talking a couple of mm difference between front and rear edges?

Rake/ castor, sorry Dave only ever done this on bikes before! Thanks Pete I'll check that.

[Pete]

Toe in needs only be 2mm or so.....no biggie. Caster is king - you need to ensure it has straight line stability at speed; not acting like a shopping trolley which is what most State-side set ups tend to do. It's all for ease of steering and a squidgy ride - not to mention on t'other side of road where the camber is opposite...............

[db]

Good explanation of castor here:

http://www.240edge.com/performance/tuning-caster.html

I have nice round-profile tyres so I shouldn't have to worry about the heavy steering that high castor can create


Future plans by the way are to replace or rebuild the strut assemblies with longer shocks, bigger brakes, spherical bearing top mounts.. oh and symmetrical A-arms

[db]

Toe in needs only be 2mm or so.....no biggie. Caster is king - you need to ensure it has straight line stability at speed; not acting like a shopping trolley which is what most State-side set ups tend to do. It's all for ease of steering and a squidgy ride - not to mention on t'other side of road where the camber is opposite...............

2mm toe-in total or each wheel?

[Adrian Worman]

Total Paul

[db]

Ta