BMW Twin Close Ratio Gearbox.
The BMW engine does not have a primary reduction from the crankshaft to gearbox as is typical in most engine configurations. This makes overall gearing a problem, particularly for small wheel sidecar outfits, with this in mind a 6.67% increase between the engine and gearbox has been incorporated. We now offer an alternative ratio more suited to solo’s and larger wheeled outfits.
The standard gearbox ratio’s are unsuitable for serious racing and have been changed, as shown below. All gears have three undercut engagement dogs to allow for rapid and reliable changes and positive retention
Both shafts supplied fully assembled and ready to fit.
We can supply both the older and newer cam forms on the input drive gear, so please specify when ordering. (Photo can be supplied to illustrate the difference).
Superfinished in house as standard.