Electrifying a bike with an internal geared hub?

[ammodave]

I have a nearly new Jamis Commuter with an 8 speed (internal geared hub) that I would like to turn into an E-Bike. The frame and forks are aluminum which seems to rule out a front hub motor (unless I switch to a steel fork). Is there any way to use a rear hub motor with internal gearing? Any other options I might consider?

 

[deardancer3]

I did a chaindrive on a nexus internal 7 speed. worked out fine.

But special conideration for a moderate power front hub motor with some fork modification might be worthy of analysis.

d
edit, I just checked and the Jammis commuter 1 had a steel front fork, but still quick release.

http://www.jamisbikes.com/usa/thebikes/street/commuter/09_commuter1_spec.html

 

[ammodave]

This is a Jamis 3.0 and the forks are definitely aluminum. Sorry to be such a nimrod but the whole E-Bike thing is uncharted territory for me. With chaindrive, are the pedals in motion anytime the motors is engaged or is there some provision for freewheeling the pedal crank?

 

[Drunkskunk]

Welcome to the forum.
I checked on that fork. Aluminum as you said, but with a nice 1 1/8th" steering tube, meaning a quality steel fork would be easy enough to get and would be suitable for a front motor if you chose that route.

Chain drives can drive through the pedals, and there are freewheels that can be attached to the crank so the pedals stay still while motor runs if you want.

 

[deardancer3]

So other than the un-advised friction drives, the chain drive and the front hub with new steel fork are your options.

How about some info on anticipated load, your terrain, hills, top speed needed, how much you will pedal, budget, if you want to do any of the install and service?

If your demands are fairly moderate, then the Hub motor is the way to go; if San Francisco hills with big loads then chaindrive..

d


edit

woops my manners are slipping.. Welcome on-board.

d

 

[ammodave]

I'm in NW Fl and it's fairly flat. Just looking for a neighborhood fun bike (20mph or less) with a range of 10-15mi. I weigh 150lbs and consider myself fairly fit but I have bum knees that limit my pedaling ability. Chain drive sounds interesting if I could find a kit that gives me a clean custom look. I would consider myself an average shade tree mechanic having maintained my own vehicles for yrs.

 

[Drunkskunk]

I'm in NW Fl and it's fairly flat. Just looking for a neighborhood fun bike (20mph or less) with a range of 10-15mi. I weigh 150lbs and consider myself fairly fit but I have bum knees that limit my pedaling ability.

Then a front hub motor will be the simplist solution.

a Nine Continents motor with a 36 volt battery will do that for you. a capacity of 10Ah will give you that range if riden conservativly. 15Ah would let you have a bit better reserve.


And Its Sacralige to even sugest this, But... You might find it works better to replace the 8 speed with a rear hub motor and run it as a single speed.
I know, Sacralige. But you very likely will never miss it once you have a motor installed. A rear mounted motor would mean no need to replace the fork.

 

[voicecoils]

Welcome to E-S.

Feel free to click my 'red commuter' link in my signature to see my bike with a small internally geared front hubmotor and rear 8 speed Shimano Alfine hub.

If you can get balanced weight distribution, it's not a bad way option.

Check Jensonusa.com for Surly cromo forks, they're inexpensive and very strong. A torque arm or 2 would still be advisable and when bolting up a hubmotor, you have to make sure every washer, bolt, and dropout surface tighten up completely flat and parallel to each other. Split washers & loctite can aid in ensuring the hub does not loosen in the dropouts.

 

[deardancer3]

Consider the following:

chain drives are not usually clean looking installs unless on recumbents

hub motors are the easiest first install.

With your load and terrain, almost any hub motor will work.

d

 

[dnmun]

you could have a steel front fork with aluminum frame. double check with a magnet right on the dropouts. i got an aluminum cannondale frame from duane and it has steel front fork, i was surprised.