Steering
Geometry
Camber
A moderate amount of negative camber will give your racer better tyre contact when the tyre is being distorted during agressive cornering. Around 2-5 degrees is probably a sensible starting point.
Caster/Trail
A moderate amount of caster angle / trail will help your steering naturally return to the centre, and assist with understeer (push). When combined with Kingpin Inclination and scrub radius, caster will also allow racers with a rigid frame to lift their inside rear tyre while cornering, which is beneficial with a live axle to avoid understeer. It should be noted this does make steering heavier, as you are partly lifting your own weight with each turn. (Image Credit - super7thheaven.co.uk) Around 2-5 degrees of (forward pointing) caster and 10-30mm of trail (steering axis ahead of wheel centre) is probably a sensible starting point.
Toe In/Out
Toe is likely not too important to Hacky Racers. Some toe in generally makes steering more stable, and toe out generally makes steering more agressive. Excessive amounts of toe in either direction will lead to tyre wear.
Kingpin Inclination / Scrub Radius
When combined with caster, KPI can help in lifting the rear wheel to improve cornering on live axle racers. See Caster/Trail section In a simple steering setup, Kingpin inclination may also be how you achieve camber, so around 2-5 degrees again is a sensible starting point.
Ackermann Geometry
When cornering, your inside wheel needs to follow a tighter radius than your outside wheel. This can be achieved through Ackerman geometry, which through a simple mechanism, turns your inside wheel more aggressively than your outside wheel. Image credit - Vehicle Steering Systems - glue-it.co.uk The typical general rule is that your steering arms should be attached at a slight angle, so if extended from the king pin, they would cross at the centre of the rear axle. (Image Credit - TomIII- Photobucket)
This is simple to achieve on rear facing steering arms, which can simply be angled inwards slightly. However, if your steering arms are forward facing, they should be angled outwards. If this would interfere with your tyres, the same effect can be achieved by crossing the tie rods on the pitman arm by the same distance that an angled steering arm would produce.
Resources
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