Speedometer drive

The rotation of the wheel (front, rear or in the gearbox) is translated and redirected via an angle drive or worm gear. The flexible speedometer cable then transmits the rotation to the speedometer itself. Within the speedometer, the rotation of the shaft is then converted into the deflection of the pointer.

What mechanical speedometer drives are there?

Depending on the installation location, they are divided into rear wheel connection, gear connection and front wheel connection. The drives for the good old Corbin accessory tachometers were bolted to the frame. The wheel rotation was taken off via a ring gear and a Bakelite gear. For the connection to the speedometer shaft, there are different threads according to diameter and pitch. The counterpart on the speedometer cable in the form of a connecting nut must be compatible.

It is also important that the gear ratio fits.

Most speedometer cable drives are available in different gear ratios. For those for gear connection, the gears must fit into each other and the number of teeth must be correct. With the speedometer worms for mounting on the wheel axle, the gear ratio is "fixed". We therefore specify them in the store. Since there were originally three different calibrations for the mechanical speedometers for Harley-Davidson, the number of revolutions of the speedometer shaft must of course match. The gear ratio in the speedometer drive ensures that this works.