Drop out

[Bud Baker]

I installed a rear hub motor on my Catrike Trail. I installed the torque arm that came with the motor kit. The hub motor fit into the 135 mm wide dropouts with the flats aligned with the flats of the dropouts. I have been having difficulty keeping the spokes tight and the wheel true. I took the rim out of the dropouts to take the wheel to a well respected builder of rims and custom bikes to see what they could do to lock the spokes. It was then that I noticed the dropouts, aluminum, were chewed up, very ragged and starting to round out. Yikes! I ask you all for your thoughts. Don't sweat it or pull the plug before you ruin your trike. They were forged and true. They are now not like before. Torque on the nuts was set to specs. A torque washer was also used. Help!

 

[J.R.]

I installed a rear hub motor on my Catrike Trail. I installed the torque arm that came with the motor kit. The hub motor fit into the 135 mm wide dropouts with the flats aligned with the flats of the dropouts. I have been having difficulty keeping the spokes tight and the wheel true. I took the rim out of the dropouts to take the wheel to a well respected builder of rims and custom bikes to see what they could do to lock the spokes. It was then that I noticed the dropouts, aluminum, were chewed up, very ragged and starting to round out. Yikes! I ask you all for your thoughts. Don't sweat it or pull the plug before you ruin your trike. They were forged and true. They are now not like before. Torque on the nuts was set to specs. A torque washer was also used. Help!

I would question the torque arm you got with the kit. It may not have been up to the task. Grin's V4 might help. Grin is very respected in the industry, their torque arms are very robust.

http://www.ebikes.ca/product-info/torque-arms.html

IF the drop out is too far worn, try a local welder that does TIG. They would be able to build up the missing aluminum. It shouldn't be too costly.

 

[Ann M.]

Definitely, there is some issue with the torque arm you have, @Bud Baker. With a rear hub motor, it's a good idea to use 2 torque arms for added safety, particularly with 500 watt+ systems. Might suggest that you find a local frame builder who could weld in a set of reinforced drop outs. Most stamped drop outs lack the structural strength to prevent "rounding out" like you're experiencing without 2 torque arms (the Grin technologies are truly the best as J.R. suggests). One other suggestion is to be diligent about pedaling a little bit as you start so that the motor isn't doing 100% of the work from a dead start.

 

[Bud Baker]

Photos.

 

[harryS]

For that, you might consider a torque plate that uses the two screw holes being used for the fender and rack mounts.

Who makes them? You, a sawzall and drill press. I only used one hole for this one, only 250W motor, but I have them on bith sides.