18, 19 or 20 tooth gearbox sprocket?

[Rookie_V#60]

Hi all,

for further optimize my longstroke I have the question which gear is for what purpose the best (no sidecar operation). Any experience?

Thanks, Rudolf

[muskrat]

G'day Rudolf.
According to my books 18 is standard. With a standard 46 rear the ratio is 2.55 : 1.
19/46 is 2.42 an increase of 5% and 20/46 is 2.1 an increase of 17%.
So speed per revs will increase by those %'s but hill starts will be harder.
Cheers

[Triton Thrasher]

Go for standard solo gearing at first.

Then when you later overgear it in search of mythical "relaxed cruising" and fuel economy, you'll at least remember how good it was to ride with the lower gearing.

[vinver]

I tried that on my A50- used a 21 tooth sprocket. Poor thing didn't have the guts at 60mph in top gear, had to gear down on long hills. I would think same effect on the A7, it will do more harm to lug the engine than to ride it as it was originally geared.

[KiwiGF]

ive recently changed the standard gearing on my a10 (with a 356 cam so slightly more hp than std, hopefully) by fitting a 22 tooth engine sprocket instead of the standard 21 tooth, the reason is that I wanted a more relaxed engine at 100km ph, its actually not made much difference to the cruising and it still seems to me to be revving a bit high, and it has meant more changes up into 3rd up hill it previously would do in top, so I would say gearing up is of marginal benefit for new zealand roads, so bsa got it more or less right. I definitely would not gear up more eg to 23 tooth.

Just my 2 cents worth!