Yuba Mundo Classic 14mm Axle


New Member
I'm looking to purchase a rear hub motor for my Yuba Mundo Classic. I'm thinking of going with one of these two kits:

BAFANG Rear Wheel 500W 48V​


Electric Bike Kit 26inch Rear Hub Motor,48V E-Bike Kit 1500W Wheel​

After doing all of my research I just discovered that my rear axle is 14mm and that most rear hub kits are either 10mm or 12mm. How do I go about installing one of the above kits on my bike? What parts will I need to fix them on my axle?
I plan on installing the rear hub with the wheel that it came with (not using the stock wheel that came with the bike).
I can tell by the diameter that the Amazon kit is a direct drive hub motor. This is a 26" wheel. Doesn't the Mondo have a 20" rear wheel? Direct drive hub motors are simple, pretty reliable, go high speeds pretty well, don't accelerate well, and use too many watthours climbing hills slowly. DD hub motors drag if ridden unpowered. About like being in 2 higher sprockets than you really are.
The bafang might be a geared hub drive motor, which climbs hills more efficiently and will use less watthours doing it. Geared hub motors will not climb 1000' slowly in an hour, that would burn the winding. They don't cool as well as direct drive hub motors. The gears may eventually wear out, but a replacement power wheel is only $350-400. My first one lasted ~4500 miles, and I was able to pedal the motor home unpowered after it wore out. No drag unpowered, even worn out. I climb >80 short hills with my geared hub motor, three of them 15% grade but 100' long. I carry <80 lb cargo.
All hub motors come with a washer with a tang on it that fits in the slot of the frame. This is a rudimentary anti-rotation device, but should be supplimented with one or two torque arms. This is a piece of steel 2 to 4" long (longer better) with a slot cut to the oval of the axle, and a screw hole on the end to connect to an anti-rotation clamp. I cut mine out of flat .100" x 1" steel with a hacksaw, a drill motor, a 5/16" drill, a #13/32" drill for the screw hole, and nicholson files to cut the two big holes into the oval shape. Takes about 90 minutes. Use safety glasses with power tools. I made the clamp out of sheet metal cut from a scrap box fan frame.
I converted my yuba bodaboda with a 26" wheel I bought off ebay. You'll find that 8 speed freewheels will not fit in the dropout, you'll have to make do with seven speeds. After riding a DD hubmotor with 7 speeds for 8 months, I converted to a geared hub motor on the front so I could restore the 8 speed rear sprocket cluster my bike came with. I could never find a 12 to 34 seven speed sprocket in stock anywhere. WIth a front motor don't use electricity on ice, slick or muddy steel plates, rock, or wet wood bridge decks. I push the bike on most of those surfaces.
You'll need a special crank tool to remove the crank to install a PAS pickup. See videos on u-tube.
As with all rear axles since the skip link chain, the axle tends to walk forwards in the frame. I put second locknuts on mine, which were very difficult to find. I ended up making them with a half inch drill and a 14 mm x 1.75 tap from victornet.com . I had to take the white connector off the wire harness & reintall it to get the lock nut on. Make a drawing of the colors before removing the pins with a pick.
Last edited: