Home THE TRIALS CAR Back End by Grant Campbell

Click on an image for enlargement & further explanation


The Back End on my car was one of the things that took a bit of getting right. Close inspection shows that I've used Kombi reduction gears, called in the trade 'Droppers'. My first car was essentially all Kombi, and the whole concept arose, not because I knew anything about 'torque reaction', but because I owned a 'real' Kombi and I knew how good the traction was on that car. In fact, I used to practice getting stuck in the mud before I knew anything about trials. At least the trials 'legitimised' this foolish practice.

Torque reaction is the key, and the droppers promote quite violent torque reaction which attempts to lift the car, in turn pushing the tyres down hard on the ground and thus increasing traction. This is actually a momentary thing but it lasts until the limit of travel is reached, quite often long enough to get the best of a section. Letting the car squat by applying the fiddle brakes, then using the throttle to make the car jump is a great technique to master.

A side benefit of the droppers is the 4" extra ground clearance.

Inside end of the radius arms. Four tubes welded into the end of a Toyota Corolla lower control arm (front). Bracket on torsion bar housing is RHS, and the mounting point is adjustable vertically. Lateral adjustment is by spacer washers.