I have a 2 roller chassis dyno. Do I put the RPM sensor on the front roller or rear roller?
There is a good deal of tire slippage and tire deformation which takes place on a twin roller dynamometer. The RPM between the 2 rollers can easily be 10% different or more. You must put the RPM sensor on the same roller as the torque absorption unit. If this is a twin roller inertia dyno, put the RPM sensor on the roller attached to the largest amount of inertia. This is typically the front roller, because the tire will better adhere to it as the torque output increases. The tire will tend to pull away from the rear roller.
