Fitted this conversion on my old Evans mountain bike. Pretty straight forward. I had to file out the front fork drop outs to allow the rather large spindle to drop in a bit further and allow the large tabbed washer to locate and prevent the spindle from revolving. although to be honest the flats on the spindle were a tight fit in the drop outs anyway. My forks were exactly at the 100mm required between legs at the spindle position. Filing the fork ends was a bit difficult with a round file having to keep the depth more or less identical on both sides. Fitting the supplied rack was a breeze but I do have a rattle( which might be the battery handle) that i need to cure because it drives me mad. The inclusion of the controller box housing being on the end of the rack is a good move although fitting all the wires and connectors in the space was a bit of a juggle. there is a locking pin to keep the battery in place but there isn`t a key switch for turning on the power( just a flat toggle switch) which means that a thief could ride away with power if they cut off your security chain. I needed to fit my pedelec controller on the left hand side because the bike has a triple chain wheel and the small wheel and lugs would have been in the way of the magnetic disk and I didn`t want to destroy the crank set. Fitting the pedelec (pedal assist) on the left was no problem but would just like to point out that the sensor (small plastic box) needs to face outwards and the magnetic disk needs to be fitted with the arrows facing clockwise (which is opposite to how you would fit it on the chain wheel side.)
A word about the pedal assist! this system assists your pedalling more when the chain wheel speeds up rather than the way my bought Powertrek Dynamo bike does it. On my powertrek, you get more help when you crank is moving slowly thus helping you to get up to a decent pace, whereas on the Alien you get more help the faster your crank is moving so as you get up through the gears to a higher gear the help drops off and leaves you on your own more or less which is when(Im my case)exactly when i need more help to keep up a decent pace. You can feather in the twist throttle at anytime to help but it means that you have to think about what you are doing more. I disconnected my pedal assist wires and just rely on the twist throttle as and when i need it. Let me just say that the Evans being a light bike to start with is a lot easier to pedal along unassisted so might well become my training bike rather than my pleasure bike. I just returned from a brisk ride of around 7 miles and felt like I had had a work out (which can be good) but my right hand had aching joints from working the throttle and when I moved my hand to change gear I tended to loose control of the throttle and there was a lag till I got control again. Some people love the set up but I find it a touch illogical. Having said that my version (36V 250W) has plenty of punch and will spin you along in top gear and full throttle at a fair old pace. If you have a half decent MTB bike laying around and you fancy an electric bike then with a bit of engineering knowledge and the alien kit you can be on the road with a decent hub motor for less than the cost of an equivalent ready to go shop bike.