laminated drive rings
I'd like to see those pics as well.
Especially if you have some pics while in the process of building, as well as finished pics.
Sorry for the delay, but the da....ng computer seems to be smarter than I am.
Tried about half a dozen times to upload some pics, but something always went wrong. Oh well, one more time. Hmmm, now it is working.
Anyway, I am running two versions of this idea. One has a 49cc tecumseh with a 1 1/2 pulley going directly to an 18 inch diameter ring with a spring loaded idler (skateboard wheel) It could be geared a bit lower except the ring would interfere with the rim brakes if it was larger. The only way it will reach max revs is down hill. Of course I am travelling over 40 mph by that time too. It gets about 90+ mpg. I have about 1800 miles on that rig. I will say that I purchased the engine from an RC aircraft enthusiast who *adjusted* a few things when he rebuilt it for me.
The other one is another rack mount on my Mongoose *mule*. That bike has been repowered by several of my hair brained ideas over the last few years, but is still going strong. This one says it is a 49cc Honda on the recoil, but it used to say 97cc as in Honda clone. Amazing what a printer and some clear coat can do.
Anyway it is running a 11 tooth clutch into a 22 tooth sprocket on the jackshaft. The other side of the jackshaft uses a 4 inch pulley with the belt driving another 18 inch ring. Both of them use an A67 v belt. The drive rings are flat....no groove cut into them. They track nicely, and it makes it easy to remove the belt if I have to peddle for an extended period of time. The belts last about 1500 plus miles. The bike chain is replaced when it stretches enough to start coming off. I drive the four stroke more because I usually pull a trailer, and the extra torque is handy. The 4 stroke gets about 135-150 mpg depending on wind terrain, and the trailer.
One of the nice things about this setup is that the ring actually strengthens the wheel. I have yet to break a spoke except once when the deralleur got caught in the wheel. I took out 11 spokes and still rode home with the ring holding the wheel straight.
I use about 6 pieces of aluminum to hold the ring in place. I have also used stitching screws to hold them in place. They seem rock solid. Just to try it I only used 6 screws once for a couple hundred miles. It was still tight when I added more to ease my nervousness.
I used a router and home made circle cutter to build these things. First I drilled a half in hole in a work bench. Then I put a 1/2 inch bolt through the hole with a nut on top. Then I drilled a half inch hole in a 24 X24 inch piece of 1/2 plywood and screwed it to the bench. This was routed to the id of a wheel....something like 22 5/8 inches I think. On top of this I screwed and glued a 24 X 24 inch piece of 1/4 inch plywood. This was routed to match the OD of the first disc and a 16 in hole was routed for the ID. On top of this I screwed and glued a 20 X 20 in piece of 3/4 inch plywood, and this was routed to 18 inches OD and the ID to match the 1/4 in plywood. After that I sanded the edges and applied several coats of epoxy resin. That's about all there is to it. I am working on molding these things out of fiberglass using a bike wheel as the outside mold. These should fit even better, and should be lighter, and of course look a bit less crude.
I do have a third ring on my home made tadpole trike using another Honda clone engine. Got to finish it one of these days. I also have another unfinished setup on another bike. This one used a 22 inch ring on the front wheel of a bike with a disc brake on the front. I plan to use my little 25 cc Honda bracketed to the caliper brake mount and have a front wheel drive. This will be my lightweight bike to throw in the trunk or whatever.
Anyway, there you have it. I have some more pics of the ring building process somewhere. I will post a few when I find them. I also have more pics of the bikes themselves if anyone has specific questions about something. Both of them are used as daily drivers, so I can take pics of more specific details if anyone likes. Thanks for the interest
Denny