Hi all-
I've been reading up the archive, looks like a good group you've got here.
I've been waiting for over a year for the guys over at cleverchimp.com to start selling their Stokemonkey kit for the Xtracycle/Surly Big Dummy bike. They still refuse to say what year they might, possibly be selling it in so I'm giving up on them and building my own. I think their design is great, I love the motor location, the use of it as a "stoke" similar to a tandem bike, the standard bike parts for the drivetrain and the fact that it's designed around an Xtracycle.
Trouble is that they are probably going to be charging close to $2k for the kit and who knows when that will be.
I'd love to get some help from you folks finding an appropriate motor/controller/batteries. One of the important design considerations is that the motor location is such that the motor needs to be very low profile, like a hub motor in order to not interfere with pedaling.
Any ideas? Thanks.
The stokemonkey kit I saw didn't look all that interesting.. anyway.. the interesting thing about the xtracycle is the extra long chain. It begs to be broken in two, right?
How about this:-
http://electric-bikes.com/bikes/kits.html#E-4
http://electric-bikes.com/betterbikes/e-4.html
It's shown on a recumbent but I think the kit is available separately.
Another possibility is a rear mounted hub motor.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Thanks David, I'm leaning twards the hub motor just for simplicity's sake, but I like the idea of using the motor as a standard "stoke". That allows you to use bike components fort the driveline as well as take advantage of the multiple gears. By mounting the motor with a freewheel and chainring setup,I can fine tune the gearing to be right in the motors most efficient range, from almost stopped to top speed. Just get the right gearing such that optimal motor speed is very similar to optimal cadence, and all the right-side, bike gearing should work perfect. I'd haveto unload the motor to shift,but that deosn't seem like a big deal.
I want both high torque and good top speed, the bike will be used for both hauling and commuting.
What don't you like about the stokemonkey design?
Perhaps look at the Cyclone "double-freewheel" BB kit? If you lengthened the bike frame, you could mount it in-between the pedals and the gear cassette. The 650-Watt motor apparently has a separate controller, opens many options for hacking and upgrades.
Don't be afraid of welding, I got a used welder at a yard sale for $100, talk to welders about technique and practice on junk. I have cut bike frames with a $20 angle grinder that had a thin abrasive wheel attached (wear gloves and a face shield, I have a big scar on my chin from kick-back!)
Don't use a butt-weld (like two fingertips touching). Cut the rear arms in the middle of the length, and slide a tight-fitting pipe over both stubs as far as you can get them. Drill holes on the outer length of the pipes where they cover the stubsand weld the holes and the ends. Add a plate or an X-brace as the longer arms will want to flex.
Get junk bikes from the trash just after Christmas or cheaply from the thrift store to get pieces of frame and components.