In some sense this is a decades old follow up to our initial torque arm experiments from this thread
https://endless-sphere.com/forums/viewtopic.php?p=211356#p211356
The standard for imported ebike hubs back then was M12 or M14 axles that were ground flat to 10mm in order to use the dropout slots for anti-rotation torque. This wasn't always adequate to stop axles from spinning and a whole industry of after-market torque arms sprung up to address this intrinsic design deficiency. The use of an M12 or M14 axles with flats also meant that the motor axle would sit lower in a dropout slot than a standard bicycle hub, enough that in many cases the disk brake caliper pads are only half engaged with the rotor.
It's possible to file the top of the dropout slot square and deeper, but that's a level of frame modification that most people would prefer to avoid.
Meanwhile, all of the non-import hub motors from that era (Wavecrest Tidalforce, Heinzmann, BionX) had an integrated torque arm which either directly clamped to the frame, or in the case of BionX had a serrated mate to the dropout face, ie proper design engineering.
Almost 10 years later and it's like nothing has changed. All the common imported motors are still using axle flats as the primary means of anti torque rotation, and we're were constantly dealing with afterthought torque arms to address that.
For us we're definitely ready to move on! Not that torque arm production hasn't been an OK little side business but it's really not the way that the industry should continue heading.
In this thread I'm going to go over our current development and testing cycle of a splined axle interface for internal torque arms that we're hoping could provide substantial benefit to hub motors.
https://endless-sphere.com/forums/viewtopic.php?p=211356#p211356
The standard for imported ebike hubs back then was M12 or M14 axles that were ground flat to 10mm in order to use the dropout slots for anti-rotation torque. This wasn't always adequate to stop axles from spinning and a whole industry of after-market torque arms sprung up to address this intrinsic design deficiency. The use of an M12 or M14 axles with flats also meant that the motor axle would sit lower in a dropout slot than a standard bicycle hub, enough that in many cases the disk brake caliper pads are only half engaged with the rotor.
It's possible to file the top of the dropout slot square and deeper, but that's a level of frame modification that most people would prefer to avoid.
Meanwhile, all of the non-import hub motors from that era (Wavecrest Tidalforce, Heinzmann, BionX) had an integrated torque arm which either directly clamped to the frame, or in the case of BionX had a serrated mate to the dropout face, ie proper design engineering.
Almost 10 years later and it's like nothing has changed. All the common imported motors are still using axle flats as the primary means of anti torque rotation, and we're were constantly dealing with afterthought torque arms to address that.
For us we're definitely ready to move on! Not that torque arm production hasn't been an OK little side business but it's really not the way that the industry should continue heading.
In this thread I'm going to go over our current development and testing cycle of a splined axle interface for internal torque arms that we're hoping could provide substantial benefit to hub motors.