Here's the original specification from the "free drive contest" thread:
Firstly thanks a heap Matt for this great idea. The timing couldn't be better for me, as I am seriously considering upgrading to an Astro 3210 motor, and unfortunately with the slightly larger diameter, it won't drop straight in to my existing setup (Grinhill Mk2). Rather than pushing the bleeding edge, (BTW I love the trike proposals here), I'm taking a different tack. So...introducing my contest entry...The Grinhill Supercommuter
- To showcase the MS Drive and RC technology to the e-biking mainstream by developing a prototype which will simplify the installation process.
- To demonstrate that an RC build can be simple to install and reliable, while weighing less than an equivalent power hub motor.
- To bring together a number of recent developments and ideas from other threads.
Suit Hardtail 26" MTB or 700c commuter.
All-in-one Rack including drive and batteries, with chain drive output.
Modular Lipo, stackable flatpacks for easy range increase. Starting with 37V 20Ah.
All aluminium, prototype will be done with hand tools/drill press only.
Chain drive to RHS using multiple freewheels on cassette. At this stage 219 chain is the preference. Note this will be subject to development occurring on the parallel drive system, refer to thread: http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=12449#p185209
Left hand drive also possible if required.
Here are some advantages for my proposal:
Some of the previous builds using Matt's drive have had difficulty mounting the drive to the bike frame. The square tube of the rack should make this simple.
Keeping everything at the back will leave the triangle free, no obstructions to pedalling, the drink bottle mounts are left free.
The wiring loom will be very short and self-contained, the only connections should be throttle cable, cycle analyst, front lamp. Could be combined into a 9-pin D plug or similar.
The rack can be used for carrying normal loads.
Some optional extras which I am presently considering (have been following relevant threads with interest) - Matt's FET-controlled power switch, y-delta switching, side cover plates.