shimanio 3hub filp flop

[Proboscis]

1 2 3 i gots a 44 tooth and a 3 gear hub (shimano) i want to make a three speed on the left side

 

[gone_fishin]

i've pondered that modification, wonder if anyone'll come up with something...

how about the speed, tho? how do you propose to shift without blowing the thing to shards?

 

[Steve]

I would think it would be much easier to install a jackshaft than to turn the hub over.

 

[Edward]

The process would be just like driving a (pre steering column lock) car with the clutch system out. Start in first accelerate to 10mph. push out of gear, shut off engine until rpms reach 0. Shift into second, restart engine, accelerate to 30mph. push out of gear, shut off engine until rpms reach 0, shift into third, restart engine, etc.
I did this with a 76 Datsun B210 to avoid a ruinous tow bill. If you do this in a modern car, the possibility of the steering wheel locking during the shut off makes this a dangerous practice.
Back to the bike, shifting gears during a coasting in neutral step, rather than shifting under power, would avoid catastrophe. -Edward

 

[psuggmog]

I have been thinking about using a two or three speed hub as a transmission. My idea is to use it as a gearbox mounted directly behind the motor. I will machine a flange and braze it to the hub shell on the left side of the hub. Add a removeable sprocket to the flange. My fabricated mounting brackets, similar to rear droupouts will be added to my frame to hold the hub. The hub will act as a multi-speed jackshaft. The primary chain is from the engine to the left hub sprocket. The secondary chain is from the pre-existing hub sprocket, on the right side of the hub, to the factory cog on the rear hub. This gets rid of the leftside add on hub sprocket. Because of the ratchet in the three speed hubs, you can't just flip the hub and use the existing gear on the left side. The freewheeling aspect of the hub also means no bump starting the engine as most of the chinese engines require. There were some fixed gear threespeed hubs made at one time, but they are rare and in the world of ebay, now very expensive. There are ways to defeat the freewheeling of regular hubs, but this requires modifing the hub internally.

 

[psuggmog]

The process would be just like driving a (pre steering column lock) car with the clutch system out. Start in first accelerate to 10mph. push out of gear, shut off engine until rpms reach 0. Shift into second, restart engine, accelerate to 30mph. push out of gear, shut off engine until rpms reach 0, shift into third, restart engine, etc.
I did this with a 76 Datsun B210 to avoid a ruinous tow bill. If you do this in a modern car, the possibility of the steering wheel locking during the shut off makes this a dangerous practice. "
It is possible to shift gears in a truck or car without using the clutch with the engine running, you just have to have the two gears turning at the same speed when engaging them. Truckers do it frequently.

 

[Edward]

My first wife's father demonstrated this technique to me using the B210,needless to say, shortly afterwards the transmission suffered a catastrophic failure from the gear grinding. Its more of an art than science best left to those driving a company vehicle.

 

[Guest]

Too bad you can't shift the engine output to the opposite side so you can use the 3 speed hub. I'm not knowledgeable enough about these hubs to crack one open and see if it can abe modified to work on opposite side.

How about using a derailer, bicycle chain, and stacking a 36 tooth, 44 tooth and a 48 tooth together, separated by washer spacers? You'd have to cut the throttle to do the shifts. I may just try it this summer when I have some time. At best it would work and at worst, it wouldn't.

 

[srdavo]

How about using a derailer, bicycle chain, and stacking a 36 tooth, 44 tooth and a 48 tooth together, separated by washer spacers? You'd have to cut the throttle to do the shifts. I may just try it this summer when I have some time. At best it would work and at worst, it wouldn't.

hmmmm? is there such a thing as a left side derailer? I know there are left side drive (LSD) components for freestyle bikes. come on you bicycle mechanics out there.....gives us some input.

Dave

 

[ringal]

gears

Interesting comments....... Derailer will not work as they are designed to have the chain drive in one direction only, and that is when you pedel..the slack chain is taken up by the sprung loaded tensioner..... Try and pedel to start the engine and this unit will wrap around and jam the chain as it is not designed for bi directional operation....

Regards Al