The project: to convert my circa 2001 Marin Larkspur hybrid road bike to electric using the 'Alien' 36 volt 700c kit available on ebay. Actually its only available in 26" but the guy who makes them did this as a special for me. He does do 24 volt 700c kits though.
Rationale: The Larkspur is a pretty good bike, weighs 12 kg according to Marin and the Alien kit is claimed to weigh 5 kg, so 17 kg overall - much lighter than any production electric bikes I've seen. I also think it'll have better gears, brakes, headset and other components than most if not all ready assembled electric bikes. The kit cost 440 delivered and the bike was a similar price back in 2001 so I imagine you could pick one up for ~100 quid on ebay or somewhere.
Assembly: Had a couple of hitches. Firstly the new rim did not seem to seat itself at the right angle (i.e. verticall) between the forks. I had to forcibly hold the wheel rim vertical and then tighten the bolts. No big problem but had me wondering why this would be the case? The only other real problem was finding an inner tube suitable for the rim. The inflation valve doesn't reach out far enough because of the funny triangular cross-section of the inner rim (most rims are flatish). Apart from that it was just a case of securing a few components to the handle bars and wires to the frame, putting the rack and battery in place and stuffing all the wires in a small bag along with the controller.
Finished result: Judge yourself from the photos but I think its pretty discreet and looks like a normal bike.
First ride: 10.2 miles journey to work. Didn't go too well, it only seemed to run on the throttle up to 8 mph and maybe assisted a bit if peddling up to about 10 mph. The one good thing I found was being able to leave the bike in a high gear and use the motor to accelerate from a stop and then start peddling. Apart from that it was a very slooooow journey. It was infact so slow that it was hard to balance at times. The 'out of the box' setting for the kit is meant to deliver 15.5 mph on a 26" wheel so I was expecting a little more on a 700c. I was pretty disappointed but didn't give up on it because I thought I might just be the controller settings or something else I could adjust.
Second ride: back from work. Using information from this forum I identified a small variable resistor linking two blue wires coming out of the controller. I cut it off as someone suggested and the performance of the bike was much improved giving around 16/17 mph. Peddling helped add another mph or two but it really wasn't worth the effort peddling more than that. At this point I have to say that it was better than any electric bike I've ever ridden. It had a good cruising speed, was very quiet and went up reasonably steep hills at about 14 mph with minimal peddling.
Battery: At the end of the run into work all lights on the charge indicator were still fully lit. After the ride home only one light out of 6 had gone out. Its hard to say what the batter life would be because the journey into work must have been in some ultra economy mode. I had been peddling lightly most of the way but not really making much effort.
Verdict: It will be a very useful tool for days when I don't feel up to cycling into work under my own steam. Better than any electric bike I've ridden including the Agattu, Lafree, Twist, PowaByke 24 speed commuter However I could wee all over it on the unmodified bike beforehand even on hills and it seemed to limit me to doing about 18 mph where I could generally get up to 25+. I'm wondering if there is any scope for improving the performance more. The seller claims that the derestricted kit will do 20 mph on a 26" wheel so I was expecting similar performance to a Mk 1 Torq on my 700c (i.e. 22 mph on the flat in good conditions). What is the limiting factor? Could I buy another controller that would drive the motor faster or somehow adjust the one I've got some more? Maybe I shouldn't have cut the variable resistor off but just turned it a bit?
Few minor quibbles - thumb throttle makes hand ache after a little while. If you raise your arm to indicate right the throttle will spring back to the off position leaving you peddling in the middle of the road with a heavy bike and no power.
It would be a bit difficult to change the tyre on the front wheel because the wire does not detach from the motor close by. A plug and socket arrangement on the wire close to the hub motor would be a good idea.
Pictures:
Rationale: The Larkspur is a pretty good bike, weighs 12 kg according to Marin and the Alien kit is claimed to weigh 5 kg, so 17 kg overall - much lighter than any production electric bikes I've seen. I also think it'll have better gears, brakes, headset and other components than most if not all ready assembled electric bikes. The kit cost 440 delivered and the bike was a similar price back in 2001 so I imagine you could pick one up for ~100 quid on ebay or somewhere.
Assembly: Had a couple of hitches. Firstly the new rim did not seem to seat itself at the right angle (i.e. verticall) between the forks. I had to forcibly hold the wheel rim vertical and then tighten the bolts. No big problem but had me wondering why this would be the case? The only other real problem was finding an inner tube suitable for the rim. The inflation valve doesn't reach out far enough because of the funny triangular cross-section of the inner rim (most rims are flatish). Apart from that it was just a case of securing a few components to the handle bars and wires to the frame, putting the rack and battery in place and stuffing all the wires in a small bag along with the controller.
Finished result: Judge yourself from the photos but I think its pretty discreet and looks like a normal bike.
First ride: 10.2 miles journey to work. Didn't go too well, it only seemed to run on the throttle up to 8 mph and maybe assisted a bit if peddling up to about 10 mph. The one good thing I found was being able to leave the bike in a high gear and use the motor to accelerate from a stop and then start peddling. Apart from that it was a very slooooow journey. It was infact so slow that it was hard to balance at times. The 'out of the box' setting for the kit is meant to deliver 15.5 mph on a 26" wheel so I was expecting a little more on a 700c. I was pretty disappointed but didn't give up on it because I thought I might just be the controller settings or something else I could adjust.
Second ride: back from work. Using information from this forum I identified a small variable resistor linking two blue wires coming out of the controller. I cut it off as someone suggested and the performance of the bike was much improved giving around 16/17 mph. Peddling helped add another mph or two but it really wasn't worth the effort peddling more than that. At this point I have to say that it was better than any electric bike I've ever ridden. It had a good cruising speed, was very quiet and went up reasonably steep hills at about 14 mph with minimal peddling.
Battery: At the end of the run into work all lights on the charge indicator were still fully lit. After the ride home only one light out of 6 had gone out. Its hard to say what the batter life would be because the journey into work must have been in some ultra economy mode. I had been peddling lightly most of the way but not really making much effort.
Verdict: It will be a very useful tool for days when I don't feel up to cycling into work under my own steam. Better than any electric bike I've ridden including the Agattu, Lafree, Twist, PowaByke 24 speed commuter However I could wee all over it on the unmodified bike beforehand even on hills and it seemed to limit me to doing about 18 mph where I could generally get up to 25+. I'm wondering if there is any scope for improving the performance more. The seller claims that the derestricted kit will do 20 mph on a 26" wheel so I was expecting similar performance to a Mk 1 Torq on my 700c (i.e. 22 mph on the flat in good conditions). What is the limiting factor? Could I buy another controller that would drive the motor faster or somehow adjust the one I've got some more? Maybe I shouldn't have cut the variable resistor off but just turned it a bit?
Few minor quibbles - thumb throttle makes hand ache after a little while. If you raise your arm to indicate right the throttle will spring back to the off position leaving you peddling in the middle of the road with a heavy bike and no power.
It would be a bit difficult to change the tyre on the front wheel because the wire does not detach from the motor close by. A plug and socket arrangement on the wire close to the hub motor would be a good idea.
Pictures: