Crazy gearbox idea that just might work...

[bhtooefr]

So, over on 'BentRider Online, someone posted a link to a Hatz diesel-powered Quest velomobile:

http://www.bentrideronline.com/messageb ... tcount=160

That got me thinking about how bicycle components could be used to build a motorized vehicle around a small engine.

Rohloff makes a 14-speed hub that's known for being rather expensive (~$1500), but known for being wide ratio (526% spread), lightweight, efficient, and absolutely bulletproof. They rate it for 100 Nm maximum input torque. Downside would be that some clutch solution would have to be found, although I think a simple centrifugal clutch would work - the Rohloff is a freewheeling hub, so as soon as the engine stops applying torque to the hub, the Rohloff freewheels, a centrifugal clutch would disengage, and the engine would fall to idle. Also, a jackshaft setup would be needed, as bicycle components are right-side drive (but that also works around the sprocket requirements).

But, the torque rating is ideal - the Yanclones that are popular around here (or were last time I was on here) are about 27 Nm, and a 3.7:1 gear reduction (which would give 15 mph in 1st, 79 mph in 14th, at 3600 RPM, on a 44-406 bicycle tire - it gets faster, obviously, with a bigger tire, although something well-streamlined could take advantage of such gearing) would not exceed the torque limits. Alternately, using the Rohloff itself as a mid-drive (which would, admittedly, require some heavy modification to the engine to get it to rotate backwards, or an UUUUUGLY jackshaft setup) would allow for even further gearing down.

Thoughts?

[gilburton]

Anyone remember this??
I only included it as it had a freewheel hub for economy.
http://www.youtube.com/user/combidrive

[Dougy]

Be careful with the letter spacing when your typing in bent rider online or you might be in for one hell of a surprise.