I just made an electrically assisted bike conversion......
Posted: Mon Jan 24, 2011 11:35 pm
Basically just using up RC gear I had lying around from other projects.
I'll post a couple of pictures on the off-chance that someone might find some useful ideas among the insanity....
I've only run it with a small battery pack, but it actually behaved perfectly, straight out of the box - ran for a couple of miles at 12.5mph & was able to climb a 1 in 7 hill without pedal assist.
Things that might be useful: 1] how to attach a small sprocket to the shaft of a brushless outrunner:
the cap screws pull a tapered thing into a tapered hole in the sprocket to grip the shaft taperlock style.
Taper reamers are about £3.50 from axminster tools (rather than ~£200 from dormer.......). 3.55degree angle on toolpost.
yeah I've got a lathe....... that is 6mm chain.
2] how to make any size or fitting of chain sprocket. Draw it in autocad (or something like) and send the dxf file to your local laser cutters. make in mild steel, stainless or ally, usually about 3mm thick - check chain specs. I got these back in 2 days for about a tenner each. Some minor fettling is advised - chamfer the sides on a grinder & clean the notches where the chain roller sit by pressing each one against the side of the right size twist drill (only takes a couple of minutes for a 90 tooth sprocket like this)
that one is an 8mm chain sprocket mounted on a southpaw freewheel on a turned down disc brake mounting.
Here's the whole bike (yes it's a skip rescue case.... ;^)
Hope there's something useful there.
The motor is actually a monster but running on a 40A ESC so not ridiculously powerful.....
I'll post a couple of pictures on the off-chance that someone might find some useful ideas among the insanity....
I've only run it with a small battery pack, but it actually behaved perfectly, straight out of the box - ran for a couple of miles at 12.5mph & was able to climb a 1 in 7 hill without pedal assist.
Things that might be useful: 1] how to attach a small sprocket to the shaft of a brushless outrunner:
the cap screws pull a tapered thing into a tapered hole in the sprocket to grip the shaft taperlock style.
Taper reamers are about £3.50 from axminster tools (rather than ~£200 from dormer.......). 3.55degree angle on toolpost.
yeah I've got a lathe....... that is 6mm chain.
2] how to make any size or fitting of chain sprocket. Draw it in autocad (or something like) and send the dxf file to your local laser cutters. make in mild steel, stainless or ally, usually about 3mm thick - check chain specs. I got these back in 2 days for about a tenner each. Some minor fettling is advised - chamfer the sides on a grinder & clean the notches where the chain roller sit by pressing each one against the side of the right size twist drill (only takes a couple of minutes for a 90 tooth sprocket like this)
that one is an 8mm chain sprocket mounted on a southpaw freewheel on a turned down disc brake mounting.
Here's the whole bike (yes it's a skip rescue case.... ;^)
Hope there's something useful there.
The motor is actually a monster but running on a 40A ESC so not ridiculously powerful.....