Problems with Rear Hub Motor installation mis-alignment solved


United Kingdom
I decided to install a rear hub motor on my wife's Giant bike but I have hit problem because the electric hub motor axle is much thicker than the one on the old quick release hub. I guess the increase in hub diameter is due to two reasons
1. Thicker hub used because of the motor torque
2. The cable from the hub motor passes through the centre of the axle.

After a struggle, due to the tightness of the axle shaft in the fork locating U gap I have managed to seat the axle, but the wheel is misaligned and there is nothing to play with. IAM therefore considering filing the fork U gap to created a little slack. Any thoughts ?
Welcome. I flied this dropout to put a larger Mundo axle into a Boda Boda frame. For reference those are popular cargo bikes in the US. It must be strait or she will have major problems at speed.


  • ShowUsaTool28.JPG
    117 KB · Views: 48
  • ShowUsaTool29.JPG
    246.9 KB · Views: 46
  • ShowUsaTool30.JPG
    168 KB · Views: 46
I used a 4.5" auto body grinder to widen the slot. When using power tools use safety glasses. Somewhat cheaper is a 3"x1/16"x3/8" grinding disk on a mandrel in an electric drill chuck. Bike was upside down on handgrips and seat. Remove display if you turn bike upside down.
Thanks to everyone for their helpful advice. I have filed a small amount off the dropout gap and it is now a little easier to seat the wheel. However, the problem still to fix is the wheel being out of alignment. After various research it appears that the wheel hub is "dished" So Iam wondering if I should engage a bike mechanic to adjust the spokes to bring the wheel into the correct centre dropout alignment. What do you think ?
I adjust spokes myself. Takes turning the bike upside down, and a small crescent wrench or spoke wrench. Loosen spokes on the too close side, tighten on the too far side. Spin wheel to make sure rim is even, doesn't wobble. Also check roundness, tire doesn't go up & down when spinning. Make sure when done all spokes plink when hit with a screwdriver, no thud sound. You may have to check that the tightened spokes don't poke into the tube. If too long, may need to file those spokes down.
Wow! Rear wheel was completely out of alignment and it was looking like I would have to take it the bike shop which,after speaking to them, sounded like an expensive re-dishing job. Anyway, after receiving a lot of helpful suggestions from a number of forum members I cracked the misalignment problem by introducing two spacer washes on the axle and they pulled the wheel right back into alignment. Also I can now select all seven gears perfectly. So, problem solved and I can now crack on with installing the rear hub motor on the wife's bike making her a happy bunny.