My first e-build about 6 months ago (July 2014) was a Gary Fisher Joshua XO. I built it as a prototype using an Electric Rider 7240 complete hub motor kit, since I had no experience with EV's, didn't know anyone who had any, and didn't know Endless-sphere.com existed. After 30 years racing everything under the sun (except boats, my worst fear is flailing in the water & getting eaten by some fish, and I KNOW I'd end up in the drink cus I crashed everything else I raced. Some shark would see me and say "Hey, there's the guy that ate my sista, Mergilla, let's killa him!", HA), I figured I was going to F*ck sumting up and this would be my sacrificial virgin to Zeus. Well, I was wrong, I installed the kit with the supplied rear rack system before the batteries were fully charged. Here......
My first e-bike "grin"... It was a fun bike, light, fast and an AWESOME wheelie machine, but riding more technical stuff ya had to sit on the handlebars to steer it. Also, the 72 volt Li-Mn batt was a bit much for a post mounted rear rack, it moved around a lot and a long heavy lever on that y-frame scared me even though I put a 650 lb. spring on the bike long ago! (If I read ES and knew the supplied rack was inadequately defective, I would have hired a team of NYC lawyers to sue the dogshit out of someone.....JK, HA!). But, my intention was to experiment to find the best weight placement/configuration for a well-balanced, powerful, light street/city hucking weapon and take that set-up to a high-quality frame and components. So, a week later, I reconfigured it here....
Hey Now! This was a fantastic bike.... Using my VW Buggy, MX, BMX, MTB-DH/ST/Freeride fabrication experience and after a couple month's of testing & tweaking like pictured 29"F/26"R wheel set-up (no good), designing a juice bag with light metal frame inside that secured the split-pack batt and "hang" it on the bike frame independently so it wouldn't affect frame dynamics unlike metal/aluminum square box solid mounts do, it was dialed in! I really liked the juice bag for its light weight, stealthy appearance (and $15 price tag) since the bike was a city hucker! So I dialed more by mounting the controller, APM display(?), lights/cell power supply in/on it and fabbed a super-easy mount system if I need a brewski and some boogerwoofer won't let me drive inside up to the bar........ 3 wing nuts, 3 straps, 3 velcro's, 3 cables (phase, hall, throttle), 3 minutes and I walk away with everything conveniently stored in a fashionable shoulder bag except motor and throttle!!!
Even better, the Gay Fish danced, it was light & balanced! Up/down Princeton University steps, 3' wall drops, 45mph on the hi-way, single track, small whip-it's..... even took it to our enduro club's, Meteor MC, hare scramble track and was sending it on small GROOMED 15-20 foot doubles! Which ultimately proved to be it's demise, after all it only had like 2.5" suspension travel.......went for a dub with shitty tires, spun the wheel in mud, came up short and cased a steep front-side....... broke the front end, frame, helmet and knee...... but the bike served it's purpose and gentlemen we have rebuilt him using modern technology, we have the capability to make him better, stronger faster then it was before........ wwwwwhhhhhrrrrriiiiiilllll here:
and here's an ES thread: http://endless-sphere.com/forums/viewtopic.php?f=6&t=65448
It's been a fun ride, I learned a lot and still learning. The Electric Rider kit is a good reliable kit with great support, a controller failed once and they replaced it, fast. They answer the phone, are knowledgeable, will spend time to explain their products and ship fast. A good company with a great business model selling a decent reliable product at a fair price, even though their supplier may or may not have the same ethics..... that said, although they sell some performance products, it seems they protect their brands reputation by selling batteries with BMS and not much info around on their controllers so knuckleheads like me (and half of ES community) can't overclock there products and say it's a POS cus it failed, IMHO.......
I say build it! It would be a challenge to mount a mid-drive on though with the bottom bracket on the swing-arm as another poster said, but can be done! I like the juice bag for the batteries, I can show you details of my set-up if you move forward with the project.