The BSA Workshop > Pre War

OHV Sloper Gearing


Hi folks,
Since recently purchasing an S29 3 speed 500 cc ohv Sloper, I have felt that it was working pretty hard at speed. 

The 1930 BSA Instruction book quotes the following gearing for a 4.93 H.P. model: engine shaft 19 tooth; clutch chainwheel 48 tooth; gearbox driving sprocket 19 tooth; rear wheel 42 tooth.

Mine are as specified except that the rear is 46 tooth, so that suggests an obvious way to drop the revs I guess.

I would be interested to know what gearing owners of similar bikes have.


I dont have a Sloper, but below is from the 1929 parts book showing sprocket sizes.

Looks like your gearing is lower than normal sidecar ratios.

Engine sprockets came with 18 - 25 teeth but no alternatives shown for the pther sprockets.

for solo work you want
Engine 21
Gearbox 19
Rear wheel 42

Changing the engine sprocket may be the eaiest/cheapest option. M20 and A10 4 lobe engine sprockets fit the Sloper and are easily available.

Its ironioc that you need to gear up just as I am trying to gear down!

Thanks for the prompt replies Julian and Dean.

Changing both sprockets should make a hell of a difference.  I wonder what on earth the bike had been used for in a past life to have such low gearing - maybe something like what was being done to the poor Panther in this picture.



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