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Hi guys, this has been covered only a hand full of times as far as I can see and none have definitive answers on actual lengths, only the theory behind changing traction arm length. So, today Christian and I from Sideways motorsport in Brisbane tested a number of different traction arm lengths in a r34 gtt and measured toe through from full droop to full compression to measure bump steer (toe changes with changes in bump). Firstly, we removed the rear coilover, and removed the wheel. Christian then made a little jig to fit to the hub of the vehicle out of stainless plate that we bolted on to the hub using the wheel nuts, then setup a string line parallel with the hub and took a measurement of the distance from the string line to the hub from the front and back of the stainless jig / plate. We then jacked the hub up to full compression and measured the change in distance from the front and rear of the plate. We then had the measurement in mm for the toe change through the wheel travel. We tried a number of different traction arm lengths, from fuly extended to as short as possible. The least amount of toe change we found was with the traction arm set to 7mm longer than standard from centre of bolt hole to centre of bolt hole. The ride height is around 330mm and camber -2 in the rear. My question is what lengths have other people tested and found that a certain length minmises bump, im asking because the jig we made is relatively crude and my guess is a little bit of human error would certainly be involved in the measurement process. Any insights on this matter are most welcome !!