A few months ago, my son decided that he would like to have an ebike, and decided that his 1992 Mongoose 325 700c hybrid (at that time in my possession) would be an ideal platform for mounting the selected mid-drive Bafang kit.  (The reasons for his decision are part of his story to tell if he so chooses.)

He decided that an Alfine 11-speed hub, with anoverall range of 409% in its gearing, with nearly uniform steps, would be the way to go, instead of the 7-speed (11-28) rear and 48-38-28 front triple as fitted to the bike.  He was able to obtain a second-hand Alfine at a reasonable price, and it fell to me to arrange its fitment to a suitable rim (for V-brakes) in lieu of the disk-brake setup in which it was mounted.  I unlaced the hub from the rim, with the old rim returned to its previous owner.  Gary and staff at Elizabeth Star fitted the hub to a suitable (32-hole) rim.

My job was to mount the new wheel in the frame, and deliver the bike to my son's home near Blackwood.  From there it would be sent for its ebike conversion. 

There was no difficulty in fitting the wheel to the frame with the components supplied.  Because of the vertical dropouts, chain tension was provided by a deraiileur-type two-pully tensioner.  As I didn't have a suitable 1/8" chain, I re-used the 3/32" chain previously fitted.  Since I had left the triple chainwheel on as a temporary measure, I decided to also leave on the front changer.  (The rear sprocket is 22t.)

I rode from home (City) to my son's place via my usual route through Colonel Light Gardens Panorama and Pasadena through to Gloucester Ave.   It took me a little while to remember to stop pedalling when changing gears - the last hub-geared bike I had ridden was my own BSA before its 18-speed conversion in 1992.  I didn't need to go down from the 48t front ring to the 38t until part-way up Eliza Pl.  The 28t ring was engaged immediately before entering Hillrise Rd from Beta Cr.  I was able to ride up that top portion of Hillrise (180m at average 18%, max 32%).  (I had only previously ridden it on my own ebike.)  The oddity with the gearing at that point was that my cadence was considerably greater than the RPM of the wheels, and the bike was "pulsing" noticeably with each pedal stroke.  (Still didn't ride up the first 150m of the fire track to Lind Ave - traction issues.)

With the Bafang motor fitted, the sprocket setup is 44t (I think) front, and 22t rear.  (I have ridden it as an ebike, up a fairly steep hiil, without going into the lowest gear.)

Summary of Hub performance: the wide range makes for both good climbing gearing, and high-speed work with a simple sprocket set-up.  Would make a good commuter setup where some climbing is involved.  Works well with the Bafang motor.

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