2018 Torque Arm Tests, Splined Interface Design and Tabbed Washers

[Balmorhea]

He is on his second front 1500w leafmotor (run with less than 400w) one torque arm on alloy front forks.

Why such a big motor for only 400W? And what happened to the first one?

 

[ZeroEm]

by Balmorhea » Aug 25 2020 12:04am

ZeroEm wrote: ↑Aug 24 2020 4:44pm
He is on his second front 1500w leafmotor (run with less than 400w) one torque arm on alloy front forks.
Why such a big motor for only 400W? And what happened to the first one?

The first one was stolen so he had none. I started out working on the one one he has now. I found out I could not ride very far sitting on a bicycle seat so I stopped on the first bike and built my trike. The first bike I was planning was going to be a AWD full suspension 29er. Dual leafmotors 52v but things have a way of changing and he was on foot. I bought him his first kit and help him put it together. That was my first then I build my mother's trike for her then built my trike. I had no plans for the front leafmotor and my brother is cheap 36v 13amp controller. He can not hurt the motor but he can up grade to more power but he would only tear up the bike and hurt himself.

 

[Morphin]

Hi
I make a custom frame design to fit the GMAC Motor. Does someone has the perimeter that the 11 holes make on the actual torque arm? And how thick is the torque plate and the torque arm? (I'm waiting until the motor is available again but in the meantime i can check if a i can design a nice rear dropout....)

 

[amberwolf]

If it helps, there's a cad model of the motor as a PDF on the product page:
https://ebikes.ca/product-info/grin-kits/gmac.html
down under the User Manual heading.

 

[LewTwo]

If it helps, there's a cad model of the motor as a PDF on the product page:
https://ebikes.ca/product-info/grin-kits/gmac.html
down under the User Manual heading.

As it is a vector PDF, it is not too difficult to import into CAD. However most of the curves are a bunch a small straight line segments so converting those back into circles and radius's is not without some room for error. Here is my "best guess" for the Grin Gmac Torque Arm spline. Note: those holes for the TA bolts could be either M4 or M5 ... this drawing shows M4. The attached zip file has DXF and DWG files.