My homemade reduction drive

[veloman]

I finally completed my longtime plan for a reduction drive. It's uber-ghetto, made from SBP shift kit parts, scooter chainring/freewheel. But i finally got that 1000w currie mounted and reduced to ~600rpms. The hard part will be mounting it on the frame, to drive the cranks.

Here are the ratios:
motor to shaft 15:80 or 5.33
shaft output is a 10 tooth bike chain sprocket, which will go to a 56 bike chainring, bolted to my freewheeling cranks.

I'm proud, yet not thrilled with this. It's HEAVY, must be 11lbs with the motor, and no mounts.


I'd really like to do a more proper design with this motor. Maybe with a belt drive of around 7:1 would be great. Any ideas?

I have no machining capabilities here, just been working with a vice, drill and hand tools. I'm sure I'd be better off just buying Recumpence's drive and mounts....

 

[AussieJester]

I'm sure I'd be better off just buying Recumpence's drive and mounts....

I was thinking the exact hing when i read you used sick bike shift kit those things are junk and ridiculously priced....good luck with it anywayz...

KiM

 

[jdcburg]

I can see it working. I suspect most of the weight is in the motor. The shaft and bearings look heavier than they need to be but I don't think the savings would be a lot. I can't tell if the 2x4 is part of it or just a temporary spacer but you could probably replace it with aluminum or pvc tubing spacers and long bolts. The unused space between the apexes could be used for mounting on the down tube or seat tube - jd

 

[recumpence]

So, off topic, I notice your Kenmore washer is missing the timer knob. I have those in stock. They are made out of metal now, so they do not break.

I can send you one if you would like.

Back on topic!

Matt

 

[veloman]

LOL, oh yeah? Yeah it's no big deal, we can still turn it okay...

The 2x3 is bolted in there, for support. It's extremely light and works well (CHEAP, easy).

The shaft and metal plates are definitely overkill (it literally took me 10-20 minutes to drill through those plates, maybe by drill bits were dull? They are my brother's high quality brass colored drill bits. I had to start with a small bit, then the 1/4") , but again, this project is all about making do with what I have. No machine shop here. The chainring is really heavy too, as is the freewheel....everything is just cheap heavy parts. The motor weighs 6lbs.

But using this motor would be good because it's very quiet, has just the right amount of power (1000w), fits well with the other #25 chain parts, doesn't need shaft support, should be reliable for a long time (since I will always have it at optimal rpm), and it's brushed, which means super easy/cheap controller.

I should have it mounted on the bike tonight, I'll get another pic. It is actually mounting VERY well, I got lucky, since I have those front derailleur clamps to work with.

 

[amberwolf]

Those scooter chainrings *are* really heavy, but the good news is that you can probably drill a bunch of lightening holes in it to cut it's weight maybe in half, and still have it hold up.

The motor I can't think of a way to lighten. The mounts can also probably have lightening holes drilled in them.

So, off topic, I notice your Kenmore washer is missing the timer knob. I have those in stock. They are made out of metal now, so they do not break.

To continue the OT Do they make the motor-to-tub coupler out of metal, too? I've already gone thru a couple of the plastic ones, and no longer dare to use more than a 1/3 of a load at a time for fear of breaking the last one I have.
http://www.endless-sphere.com/forums/download/file.php?id=40845
I've been pondering using a sliced-up pulley and some bolts to build a metal one out of, but I'm not sure it will work.
last breakage:
http://www.endless-sphere.com/forums/viewtopic.php?p=281517#p281517
and first breakage:
http://www.endless-sphere.com/forums/viewtopic.php?p=268579#p268579