BigBlue
Active Member
I decided to start my own thread as I was posting to another members thread and wanted the information in one place. This is a proof of concept idea. I'd like the ability of using my motorized bicycle off-road.
I have been thinking of building a 2 wheeled drive (2wd) motorized bicycle for some time. I am currently finishing building a custom longtail motorized touring bicycle. It will be powered by a 51cc (3.2hp) Zenoah Goped GZ51N that I purchased several years ago. The engine will be connected to a Staton 18:1 dual output gearbox. I plan to a 72cc (4.6hp) Zenoah leaf blower engine that will have to have a custom mount and flywheel made, but that's another post.
My idea is to connect a flexible shaft to the outside shaft and connect it to spiral gears that power the front wheel. Several companies have sold bikes in the past with this concept - BWA, Jeep and Ovation. Christini currently makes a similar bike, as well as a 2wd motorcycle. Some of the other companies used plastic straight bevel gears. Here's some sample pictures of other companies products, showing the front drive. This is how Jeep, BWA, Christini and Ovation, attach(ed) the bevel gears on the front wheel:
The first picture is the Jeep version; the 2nd is the BWA version; the 3rd is the Christini version; and the 4th is the Ovation version. it looks like the Jeep and Christini are the same or similar products.
I recently purchased a set of spiral bevel gears from Ebay. The were $15.39 with free shipping. If this idea pans out, then I'll purchase some better quality gears.
Here are the specs and pictures of the spiral bevel gears. The depth of the crown (large gear) is 0.325 in the flat area. The flat area on the face of the large gear between the bevels is 50mm.
The last picture shows a comparison of the drive side freewheel (15t) to the large spiral bevel gear.
My idea with the spiral bevel gears is to mount the small gear like the Jeep and Christini. I plan on using a BMX flip flop hub on the front wheel and make a custom mount that screws onto the small side of the flip flop hub. I have some 2" (50.8mm) aluminum rod and need to purchase a 30m X 1 tap for $36.88 on Ebay to make the adapter. Some of the BMX flip flop hubs are 110mm wide and have a small 30mm freewheel and a large freewheel. It is also possible to remove a nut or spacer on some hubs to reduce the width to 100mm.
I would have liked to use a 135mm front fork and a freewheel hub, purchase a ready made 55mm disc brake adapter, but it would have left 1mm between a 5mm bolt head and the bevels. The spacing for the bolts on a 55mm disc adapter is 44mm, the bolt heads add another 9mm and the area between the bevels is 50mm.
My plan cut the shaft off the rear of the large gear with a fiber wheel attached to a die grinder which will be mounted onto a tool post holder on my mini lathe. I then will have to purchase some M42 Cobalt drills and end mills to work on the large spiral bevel gear, so I can mount it to the adapter with some 5mm bolts.
For the small gear I'll make a shaft that steps from 11mm to 5/8".
I have to purchase some additional tools for my lathe before I can work on this idea and also have to finish my current build and work on getting the 72cc engine mounted.
Other uses for the bevel gear drive that could be connected to a PM motor to generate electricity. The motor could be bolted to the front fork. Or after all the expense and time, use the flex shaft to power a blender
Chris
AKA: BigBlue
I have been thinking of building a 2 wheeled drive (2wd) motorized bicycle for some time. I am currently finishing building a custom longtail motorized touring bicycle. It will be powered by a 51cc (3.2hp) Zenoah Goped GZ51N that I purchased several years ago. The engine will be connected to a Staton 18:1 dual output gearbox. I plan to a 72cc (4.6hp) Zenoah leaf blower engine that will have to have a custom mount and flywheel made, but that's another post.
My idea is to connect a flexible shaft to the outside shaft and connect it to spiral gears that power the front wheel. Several companies have sold bikes in the past with this concept - BWA, Jeep and Ovation. Christini currently makes a similar bike, as well as a 2wd motorcycle. Some of the other companies used plastic straight bevel gears. Here's some sample pictures of other companies products, showing the front drive. This is how Jeep, BWA, Christini and Ovation, attach(ed) the bevel gears on the front wheel:
The first picture is the Jeep version; the 2nd is the BWA version; the 3rd is the Christini version; and the 4th is the Ovation version. it looks like the Jeep and Christini are the same or similar products.
I recently purchased a set of spiral bevel gears from Ebay. The were $15.39 with free shipping. If this idea pans out, then I'll purchase some better quality gears.
Here are the specs and pictures of the spiral bevel gears. The depth of the crown (large gear) is 0.325 in the flat area. The flat area on the face of the large gear between the bevels is 50mm.
The last picture shows a comparison of the drive side freewheel (15t) to the large spiral bevel gear.
My idea with the spiral bevel gears is to mount the small gear like the Jeep and Christini. I plan on using a BMX flip flop hub on the front wheel and make a custom mount that screws onto the small side of the flip flop hub. I have some 2" (50.8mm) aluminum rod and need to purchase a 30m X 1 tap for $36.88 on Ebay to make the adapter. Some of the BMX flip flop hubs are 110mm wide and have a small 30mm freewheel and a large freewheel. It is also possible to remove a nut or spacer on some hubs to reduce the width to 100mm.
I would have liked to use a 135mm front fork and a freewheel hub, purchase a ready made 55mm disc brake adapter, but it would have left 1mm between a 5mm bolt head and the bevels. The spacing for the bolts on a 55mm disc adapter is 44mm, the bolt heads add another 9mm and the area between the bevels is 50mm.
My plan cut the shaft off the rear of the large gear with a fiber wheel attached to a die grinder which will be mounted onto a tool post holder on my mini lathe. I then will have to purchase some M42 Cobalt drills and end mills to work on the large spiral bevel gear, so I can mount it to the adapter with some 5mm bolts.
For the small gear I'll make a shaft that steps from 11mm to 5/8".
I have to purchase some additional tools for my lathe before I can work on this idea and also have to finish my current build and work on getting the 72cc engine mounted.
Other uses for the bevel gear drive that could be connected to a PM motor to generate electricity. The motor could be bolted to the front fork. Or after all the expense and time, use the flex shaft to power a blender
Chris
AKA: BigBlue
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