Road gearing for mds engined scotish

[taxiden]

Hope i'm doing this right,not good with commputers.wont be doing
trials just b road riding,any sugestions on g/b rear sprocket sizes....................taxiden

[John Wakefield]

Hope i'm doing this right,not good with commputers.wont be doing
trials just b road riding,any sugestions on g/b rear sprocket sizes....................taxiden

For road use you need to aim for around 6 to 1 overall top gear ratio.
The engine & clutch sprockets on the 31/32A series Villiers engines are 20 & 43 thus making primary ratio of 2.15 to 1. So you need a final drive ratio around 3.85 to 1, so if you have a 15T gear box sprocket you will need a 58 rear. So what ever your current gearbox sprocket is multiply it by 3.85 & fit the nearest size rear sprocket. If the g/box has trials ratios you should have a low enough 1st & 2nd gears for any off road stuff ie green lanes.

[taxiden]

mds road gearing

Thanks for that John,spot on, primary 20/43 ,current gearing 15/60,I'll try a 58.Gearbox marked WR(M) 151 duse that mean any thing ?
Regards denny.

[John Wakefield]

Thanks for that John,spot on, primary 20/43 ,current gearing 15/60,I'll try a 58.Gearbox marked WR(M) 151 duse that mean any thing ?
Regards denny.

Dont know maybe wide ratio!!

[scott151]

Hi,

WR does mean wide ratio, the 151 bit will probably actually be 15T as that was the standard final drive sprocket size for that gearbox. (15 teeth)

A trials gearbox will be ok for the road but not ideal because of the low 1st and 2nd with a big jump to 3rd.

Good luck with your project.

Scott