Suspension Geometry for Wet Western Cape Rally Stages

Wet gravel does not forgive a lazy alignment sheet. The car that felt planted on a dry recce will start hunting for grip the moment the surface turns to mud, and the first place that shows up is the front end pushing wide on entry. The build in these notes is a rear-wheel-drive rally car that ran two events in the Western Cape before the crew stopped chasing power and started chasing geometry.

The original setup ran a fairly aggressive static camber at the front, which worked on tarmac but chewed the inside shoulder of the tyre once the stages got soft. Caster was left close to stock, and that turned out to be the bigger problem. On the long transit sections between stages the car wandered under braking, so the driver was making constant corrections just to hold a line. The fix was to pull camber back a degree and add caster, which settled the steering and gave back some straight-line stability without killing turn-in.

Ride height was raised after the first event. The car had been sitting low enough that the sump guard was ploughing through corrugations, and the bump stops were doing the work the springs should have been doing. Reworking the stops and lifting the car a little stopped it from skipping across the rough stuff, even if it cost a small amount of body control on the smoother sections.

Tyre pressures were logged across two compounds through the weekend. The softer compound came up to temperature faster but changed the balance the driver had just dialled in, so the crew adjusted pressures between stages rather than chasing the setup again. Those notes are the part worth keeping.