Can I use a Jack shaft as a swingarm axle?

[ironbutt]

I'd like to add a swingarm to my Motovox 212cc Mini.

I'll probably get it made locally rather than buy one.

I know that for the chain tension to be steady and not jump off while using a swingarm, it's best to use a jack shaft close to swingarm and inline with the angle of the rear tire/sprocket.

Is it possible to use a jack shaft as the axle for a swingarm so that the travel arc is identical and also to reduce complexity and fabrication work?

Would I have to use wheel bearings in order to support the RPMs of the jack shaft and the weight of the rear wheel?

Any help, suggestions or wise tales of your experiences is greatly appreciated!

 

[MrC.]

May be run the jackshaft through a tube that is bushing or bearing as the pivot.
I think you are over thinking ot though.
MrC.

 

[itsid]

^^ THAT!

Yes, you can run a jackshaft as your swingarm pivot;
BUT
you'd need a battery of at least six bearings to do so in a reasonable manner, two for the sprocket support and another two to support the swingarm, then another two ON the swingarm to allow the jackshaft to rotate freely.
that also means you'd need a way to mount four -more or less evenly spaced- bearings on the frame itself. which is a pain all on it's own.

MUCH easier to use a swingarm tube with bushings (for the bit of movement the swingarm needs)
maybe two large ID bearings if you prefer,
and a jackshaft inside said tube just as MrC. mentioned.
again with it's own two bearings as a supprt.

'sid

 

[Grimm]

why not use a rod for the swing arm and have the sprockets on a tube with bearings inside? only would need 4 bearings, 2 of which could be bushings for the swing arm movement. a couple of clip grooves or even shaft collars to keep the sprockets in line.
correct me if you see an issue, i had thought of using it on my own...

*edit* see attached picture

 

[chancer]

Shaft Collars. But get the good Split ones not just the cheap set screw ones.

 

[itsid]

why not use a rod for the swing arm and have the sprockets on a tube with bearings inside? only would need 4 bearings, 2 of which could be bushings for the swing arm movement. a couple of clip grooves or even shaft collars to keep the sprockets in line.
correct me if you see an issue, i had thought of using it on my own...

*edit* see attached picture

that could totally work too of course..
if you can get it to align with the wheel and engine at the same time without shifting the engine sideways.
And due to the width your heel might get closer to a rotating sprocket than necessary... so you'll likely need a cover.

The only downside though is that you cannot just swap the sprockets to adjust the gear ratio but that's nothing but an inconvenience really.

'sid

 

[Grimm]

true, the gear ratio would have to be changed by the TAV and rear sprocket like a non suspension bike.