Ebikeor
1 µW
- Joined
- Feb 4, 2010
- Messages
- 4
0 back lash freewheel approach. When you use a freehub driver such as a Sram Dual Drive or a single speed freehub driver, the larger the hub sprocket you use the more backlash of the the paws from the freehub will be effecting the amount of backlash and sprocket run out. The bicycle type of freewheels added to the freehub driver have more backlash than the freehub drivers plus a lot more run out that is multiplied by the OD of the large sprockets. The engagement from just the paws in the freehub can cause damage to them when speed shifting under loads from high torque motors above 2000 watts of power. The extra larger bang from a bicycle freewheel will usually take out the freewheel before the freehub paws but both can be damaged when over looking the clunk effects.
In going to a higher quality and and stronger parts than bicycle parts have to offer there is a cost effective way to mitigate the problems you will incur at some point.
It's not if but when! With a large chain sprocket the hub run out or a sprocket that does NOT wobble at all is very important to get the best efficiency of your drive train and have it last many years with minimal maintenance.
What may be helpful are parts to achieve this at a cost effective price. Depending if some parts can be modified or completely made to order from existing suppliers of these parts would need to be researched for cost.
The base parts would be a industrial 35mm CSK freewheel and shim to be press fit onto a freehub driver. The cost would be $25. for the freewheel plus the cost for a custom shim to be made and pressing it together. The next most important part is a $40. 50mm ID gokart type sprocket hub that can be bored to 70mm to fit the OD of the CSK freewheel/bearing OD for a clamp on fit. Research will need to be done to determine if the sprocket hub clamping bolts will be missed when boring from 50mm to the 70mm ID size required of the sprocket hub. The next thing to take into consideration is if you can take the hub width down to at least .75" by a mill or a lathe. Once a prototype is made a gokart sprocket hub manufacture would give a excellent price for making them in lots of 100 or so. About $40. each or less!
With a standard 6 hole gokart sprocket bolt pattern there many gokart sprocket companies that will make you any type of sprockets with many sprocket blanks to choose from. There is already a great slection of many #35 and #219 sprockets that work well for Ebikes. Rocket Sprockets could even make some large dia skip tooth 219 or #35 sprockets for your needs.
In going to a higher quality and and stronger parts than bicycle parts have to offer there is a cost effective way to mitigate the problems you will incur at some point.
It's not if but when! With a large chain sprocket the hub run out or a sprocket that does NOT wobble at all is very important to get the best efficiency of your drive train and have it last many years with minimal maintenance.
What may be helpful are parts to achieve this at a cost effective price. Depending if some parts can be modified or completely made to order from existing suppliers of these parts would need to be researched for cost.
The base parts would be a industrial 35mm CSK freewheel and shim to be press fit onto a freehub driver. The cost would be $25. for the freewheel plus the cost for a custom shim to be made and pressing it together. The next most important part is a $40. 50mm ID gokart type sprocket hub that can be bored to 70mm to fit the OD of the CSK freewheel/bearing OD for a clamp on fit. Research will need to be done to determine if the sprocket hub clamping bolts will be missed when boring from 50mm to the 70mm ID size required of the sprocket hub. The next thing to take into consideration is if you can take the hub width down to at least .75" by a mill or a lathe. Once a prototype is made a gokart sprocket hub manufacture would give a excellent price for making them in lots of 100 or so. About $40. each or less!
With a standard 6 hole gokart sprocket bolt pattern there many gokart sprocket companies that will make you any type of sprockets with many sprocket blanks to choose from. There is already a great slection of many #35 and #219 sprockets that work well for Ebikes. Rocket Sprockets could even make some large dia skip tooth 219 or #35 sprockets for your needs.
