Forum

[Graham43]

I know that I can go up a tooth on the engine sprocket to improve cruising speed on my Electra X but to avoid removing a fair bit of the near side does anyone make a large sprocket for on the back wheel?

[Graham43]

...sorry meant to say 'larger' ...

[Exile]

See the catalogue... page 163. Then give H's a bell..

[Bullet Whisperer]

Hi Graham, a larger sprocket on the rear wheel would lower the gearing. 38t is the smallest for the rear wheel and usually comes as standard, cast as one with the brake drum. Regards, Paul.

[Tim NZ]

If you had been after a LAGER sprocket, I may have been able to help?

[Bullet Whisperer]

Lager - now you're talking my language, Tim ! Regards, Paul.

[PeteF]

Mr H sells a bolt on sprocket system but again, smallest is 38 teeth. I think the problem is that the brake drum won't accept anything smaller.

[jefrs]

A larger rear sprocket would lower the ratio, equivalent to using a smaller cog on the gearbox drive. To improve cruise you would want a smaller rear sprocket but the smallest you can fit is 38T because it fits around the brake drum. Larger rear sprockets are used for trials bikes. The EFI motors will take a 19T drive cog on the gearbox without modifying the casing, at 20T the casing has to be reduced. Fitting the next size up wider rear tyre, the alternate size, would be equivalent to about half a tooth extra on the drive cog, due to slightly more height to the tyre and hence greater outer diameter.

[jefrs]

Changing the gearbox sprocket is probably less expensive the rebuilding the rear wheel to change the rear sprocket. Yes you do have to strip out the side of the gearbox but to alter the rear sprocket you have to change the rear hub. Fairly simple cover off, change cog.



If you want to improve the cruise you need to raise the final drive ratio not lower it. This can reduce ultimate top speed by a couple of mph, as a higher ratio reduces the effort the motor can provide to the wheel (rather the point of having gears).



To me the cheap option to increase the final drive is to use the alternate size larger tyre (varies according to bike model). I intend to do this but will wait until the cover has worn a bit more.

[papasmurf]

What rebuilding of a rear wheel to change a sprocket? (Puzzled.)