Trek to Truk - Hybrid Commuter Bike Conversion
I work in Montreal (Griffintown) and have about a 4.5 km urban commute one way. The distance is no issue – relatively flat or downhill in the morning and (feels like) all uphill at night including a last 500 meters at 9 – 11% grade. An unpleasant struggle to end a long day at work.
There is also heavy traffic congestion on my route and endless construction detours populated by exasperated motorists and distracted pedestrians staring at their cell phones.
Decided to take my wife’s disused small frame Trek hybrid and convert it to a commuter Truk, complete with 350 watts of PAS to help me get up the hills in the heat of summer. The small frame is actually very maneuverable in a mix of heavy car / bike / pedestrian traffic over city streets which are in an atrocious state of repair.
Carbon fiber front forks ruled out a front wheel motor drive and the small frame meant that there was not enough room in the triangle for a battery mount.
Found what I needed at ebikeBC – 350 watt rear drive motor on a 700c wheel (but no freewheel sprocket) with controller, throttle, PAS etc. and a small 8.5 A-h bare battery – all at a very competitive price – and backed by super service from Ali that knows his products well. Delivery was about 6 working days which is not bad for prep + cross-country parcel post. Looked like the unit had been assembled and tested before shipping.
Took about 2 weeks for a local bike store to find a freewheel sprocket – should have just ordered one off the internet. The Trek had a 9 gear sprocket so I ordered the same, but, in retrospect, a seven gear sprocket (or less) would have done to job. Had to add some extra washers on the axle to compensate for the width of the 9 gear freewheel and adjust the rear derailleur anyway – and with the PAS I now realize that I could get by with only a big ring and 3 gears on the sprocket.
The rest of the assembly was pretty straight forward except that the magnets supplied to activate the brake mounted motor cut-off microswitches were too weak and had to be replaced with stronger ones (a couple of bucks at the local hardware store) and the crank design on the Trek forced me to cut all the little fingers out of the PAS magnetic impulse ring and epoxy it into place. The advice in the manual to use (high pressure, in my case) rim tape and tighten the spokes after a few rides is also not to be ignored.
Very happy with the results. The uphill commute now takes about the same time as the downhill one and I arrive feeling that I have gotten in some exercise but not overheated and in need of an immediate shower before doing anything else. This bike is now my first transportation choice when I want to get anywhere around downtown fast, with a minimum of traffic and parking hassles.
Ronald Denom
Montreal (Griffintown)
June 2016
