he Direct Drive front wheel drive build is for builders that want regenerative braking (useful for descending), but do not want to build custom brackets for an all wheel drive bike.
After building this bike, we realized that the torque generated by the motor is too large for the aluminum frame and had to custom fabricate stainless steel torque arms. So while you might save a little on cost, we strongly recommend you install a solid torque arm, preferably on both sides of the wheel, if not manufacture your own. With that in mind, I would probably recommend either the $1,000 build, which does not have regen, but is a lot easier to assemble or the all wheel drive build, which is way more robust, safer, and much more capable.
This handcycle was built using Grin’s ready to roll kit. The full parts list with links to everything I bought to build it can be found here. Installing all the hardware is fairly straigtforward for the mechanically inclined. The most complicated part is the custom torque arm, which you should use if you plan to have a meaningful amount of regen braking. Every time you hit the throttle and then hit the regen brake, the axle will fight against the torque arm and if there is any movement will eventually loosen the bolts. This happened to me and the front wheel jumped out of my dropouts and needless to say I was fortunate to have been moving very slowly when it happened.
You can find the CAD files we used for the torque arm here. You should install this torque arm on the drive side of the wheel and can use the V3 torque arm on the non-drive side. Note you have to bend the tab to fit around the frame and tap a 5mm hole for the screw you will use to tighten the torque arm around the axle as seen in the picture on the right.
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More coming soon (e-mail Anatol at anatolpoppe@gmail.com if you want this entry finished)