[geeks] Electric bike?

[Sheldon T. Hall]

 Saith Francois Dion ...
> I said ...
> > Alternatively, just hire a local bike racer and have him push you.
> 
> Hehehe... I had a good laugh there! I used to ride with some friends
> in college and when one would get tired, we'd push the person. It
> worked.

Since I was usually the push-ee, especially uphill, I rather liked it,
myself.
 
> Now back to your question: does a single speed setup work?
> 
> Yes. In fact practically every commercial unit is setup single speed.
> Some hub motors are 2 speed with internal gears. Then you have the
> Cyclone, Optibike and Giant Lafree that uses the chain and benefit
> from multi speed. Great to go up hills obviously.
[snip]
> Based on my different tests, I've come to be really interested in the
> power thru the chain type of drive.
> 
> One guy has an interesting solution with an intermediary shaft, but it
> requires some pretty intrusive modifications :)
> 
> http://www.jstraubel.com/ebike/ebike.htm

Bletch.

> I've just been trying to figure a mechanical way to drive through the
> regular chain.

You need a co-axial arrangement through the regular bottom bracket.  The
motor drives a sleeve inside the BB, and the normal BB axle is inside of
that.  Two layers of bearings, of course: BB-sleeve, and sleeve-axle.  The
chainrings are on the sleeve, and a one-way clutch lets the BB axle (and
thus the pedals) drive the sleeve.

> BTW, What kind of road bike you got?

Since I can't really ride any more, I'm down to two.  A very early seventies
Mercian (probably off-the-peg) I bought used, and a Geoffrey Butler I had
built in (I think) late '73.  The Mercian was, in theory, a dual-purpose
racer-tourer, but it's a pretty relaxed frame and I've only used it as a
tourer.  The GB is more of a time-trial bike.  

At one time I thought I was going to be a racer, but every time I see some
Tour de France videos, I can see that I was deluded.  I'm too heavy to be a
climber, and too cognizant of personal safety to be a sprinter.  Big
rouleurs don't win races, but they can do OK in time trials.  Unfortunately,
I sucked at that, too.  

-Shel