I bought a couple of the Cute 128 motors from BMSbattery last year with the intention of building a bottom bracket driven set-up (or two); a year later and I finally got a little time to start work on the project. This first build is a test sled of sorts, to work out the kinks and see what needs to be improved as I'd ultimately like to power my Kona Stinky with a small geared hub running either a BB drive or some jack shaft variant. The frame is a 22" Surly 1x1 I picked up on closeout from one of the big online bike stores a while back. I didn"t take any before pics of the bike, but it looked a little something like this.
I stripped the orange paint (well, most of it) and then welded a 1 1/4" square tube to use as a mounting point for the hub motor. Don't look too close at these welds, they're ugly enough to blind ya! I was a little nervous mig'ing the 1/16" thick square tube to the THIN walled cromo frame.
When I started this build a couple weeks ago, I was using simple U-channel I bent out of 1/8" x 1 1/4" bar stock to hold the hub motor as a mock-up. I decided to try running it under power with this design, but It quickly bent and derailed the chain. so back to the drawing board I went and came up with this monstrosity.
Weighing in just shy of 2 lbs.
There's two axis of adjustment built in: fore/aft and right to left.
Here's a couple pics of the motor I'm using. That's a 17 tooth sprocket bolted on. I used the three side bolts and shimmed the sprocket out with some washers.
Weighs in around 6 lbs 6 ounces.
I've used u-bolts and electrical conduit straps to mount controllers and battery boxes to frame tubes on prior builds, but was never really happy with the result. So I decided to try building my own. I picked up several different inside diameter sized pieces of cromo tubing from aircraftspruce. The idea is to chose a tubing size for your clamp that just fits around your frames tube. To illustrate the process, this is how I made my battery mounts.
I cut a 2" piece of tubing and then used a jig I made to mount some 3/8" tubing (for the bolt holes) perpendicular to the main tube.
I then ended up with these (the 1" version I use to mount the controller to the seat tube).
I cut those in half, as well as cut-off a couple M6 x 1.0mm bolts.
I then cut a few slots in the smaller bolt tube so I could get a little better bite on the stud with the welder.
I put the other half of the clamp on to make sure it'll fit after welding and then hit it with the mig.
To make the battery holder part, I used 1/8" x 3" flat bar and drilled some holes in the corners to hold a couple u-bent bars.
I tacked the bottom of the u-bend into the flat stock from the underside to leave a clean surface for the batteries.
With the clamp mounted to the battery holder.