The solution I ultimately used for a hill climber only motor was to run a second chain on the big 34t granny gear on my rear sprocket spool up to a hub motor mounted on a home-made mount that goes where the right side rear pannier bag would normally sit above the rear wheel sprocket spool on that side of the rear wheel with a 16t six bolt mount sprocket on the left side disk brake mount side of that bare hub motor with no spokes or rim on it (an available aftermarket part that people use to make flip-flop fixie/single speed wheels out of rear hubs designed for a six bolt disk brake mount on the left side of the hub). That made it so the hub-motor was geared down with a 2.125-to-1 gearing ratio through the second chain which doubled the hill climbing torque produced by the hub-motor (a small 250watt front geared hub motor) while cutting its optimal power range speed in slightly more then half so it worked out as a perfect assist (still have to pedal a little bit but its like riding a tandom with a very strong cyclist as an unseen, quiet, and obedient stoker to help you up the hill) when climbing a steep hill at about 7-mph or so because of the gearing down which keeps the little hubby spinning along at a higher speed were it puts out the most power and that power is turned into multiplied torque through the gear down.

Yes, it is true that with the second chain on the big #1 position granny gear cog on the rear I can't shift the main chain to that sprocket or the #2 position sprocket either and just have the top 5 gears out of the 7 gear rear spool I have on that bike but with the extra help on the hills that set-up gives me I don't need them anyway.

I cut out the back side of the right side pannier bags for that bike and put in an elastic band so it snaps over the mount that is welded to the frame and (now permanent) over rear wheel pannier rack and acts as a cover over the motor and its controller and small Li-Poly RC type pack battery which gives me a little over 30 minutes of extra hill climbing power provided I only use it in short bursts to give the pack time to cool. Little off-balance with the weight all to that one side until I put stuff in the left side pannier on the other side of the rear wheel to balance things out and then it is all good and just like running with two pannier bags with a few pounds of stuff in each. Also very stealthy with everything tucked under the right side pannier bag which serves as a cover and you have to look really close to notice the second chain on the rear granny gear sprocket going up into the pannier bag to realize its not all human only powered.


I do understand the desire though to not have to mess around with rigging something like that up and having a dedicated internal geared hub-motor on the market that was geared down more then most and designed specifically to be used only for climbing hills and you can pedal faster then the motor can go when on the flat and then power it off of a small battery and controller that all fit in an under the back of the seat bag or such that has just enough battery juice to give a few short burst of assist up the hills.