An 83 y/o friend of mine rides a scorpion trike with the 3speed hub and 10 gear cassette. Doesnt want to lose the gearing by replacing the rear wheel with a hub motor but needs some electric assist up the hills. Doesnt like the ride kick trailor. He needs a system that will drive the chain not the wheel in order to use all those gears. Any suggestions?

Try Ebikes.ca and their Stokemonkey mid-drive setup.

Also look into a Bafang 8fun BBS02 crank drive...

+1. That is what he wants.

+2

Why do you guys prefer mid driver over rear or front hub motors?

Crank drive has some nice advantages:

- location of mass better for handling
- gearing ratio is changeable to exchange speed for torque and vice versa
- both wheels remain easier to remove for repair

Rob, you make a good point on the advantages of a mid motor. Do you mind sharing the disadvantages?

Sure. In the interest of fairness...

- generally more expensive
- more mechanical complexity
- harder on pedal chain
- totally dependent on the pedal chain (a series rather than a parallel drive)
- not as simple to install and use

With that being said, which type of motor do you prefer? I personally like the rear geared hub motors. I find it has good torque, light weight and looks more stealthy.

I like both and don't have a preference until the usage is defined. For example, a crank drive with a variable speed rear hub is a combo that is nice to use. With a derailleur, shifting - at least shifting in a way that doesn't shorten component life - gets more fussy and results in annoying short periods of no assist. The nature and abilities of the user are also huge when it comes to selecting the best option.

I do recommend something like the eZee geared hub from Grin when people ask. Unfortunately, even geared hubs are heavy and don't work well with suspension. I do a fair bit of riding with no power assist so what I really don't like are direct drive hubs of legal power level - they are too heavy, they are relatively poor hill climbers and they have too much drag when not in use. But that's for me and my usage profile...