geared front hub motor for Mongoose Kong?

[kylerlaird]

I've been collecting electric bike parts for years. I finally have a project that's forcing me to actually make a bike...or five; for Christmas this year, my girls (6, 9, 11 & wife) decided that we can only give things that we make. I want to make(/assemble) electric fat tire bikes for all of us.

I recently had some trails dozed through the woods behind our house. We've been enjoying walking, running, and driving the ATV on them. My youngest especially likes driving the ATV back there. She has just begun to learn to ride a bike. (I failed her with the Strider...) I think an electric fat bike would get her interested and be fun for everyone.

As a starting point, I ordered a Mongoose Kong (https://www.amazon.com/Mongoose-Featuring-High-Tensile-Drivetrain-Mechanical/dp/B00UQ7RBFE). I read in another thread that it uses a 100mm bottom bracket. I have no experience with BB torque sensors, but I'm hoping to make this work:
https://www.cycmotor.com/product-page/torque-sensor-bb-for-68-83mm-100mm-bottom-bracket-version
I'm leaning hard toward a PhaseRunner (https://ebikes.ca/product-info/grin-products/phaserunner.html) controller but I'll make my own if necessary.

I'm currently hung up on the motor. I want a front hub motor for "all-wheel drive." It's going to be low speed and short but steep hills, so I much prefer to have a geared hub. The bike has disc brakes, so I'm looking for a motor with round axles and a torque arm. A side-exit cable would be easier to install and protect. Clutchless would be ideal to add some regen braking.

Where can I get such a motor? The closest I've found is the Heinzmann Cargo Power but it's huge. I'm thinking of something in the 250-350W range. And light.

I'm most anxious about the motor but I welcome suggestions on the entire build.

Thanks!

--kyler

 

[2old]

You need to measure the front hub width. It's probably 135 mm (5 1/3" or so), and if so it's what many kits have for rear hub systems. Also, your bike probably has wheels with 36 spokes which is what many rear kits specify. Also, probably possible to locate front kits wide enough and may even have built wheels (check e-bikeling).

 

[kylerlaird]

Excellent! The first Kong I ordered looks like it's on a slow boat but as soon as I get it, I'll measure. Being able to use a rear hub motor would bring great flexibility. GMAC???

Now to make sure I have the bottom bracket all sorted out. BTW, does anyone run the BB sensor cable *inside* the down tube? Running the cable straight out the bottom of the BB of a kid's fat tire bike feels like I'm building a sheer.

 

[E-HP]

Have you thought about battery placement yet? Looks like a candidate for a custom triangle pack.


Sent from my iPhone using Tapatalk

 

[kylerlaird]

Exactly. I've got a box of cells that I hope I can make fit that shape along with the PhaseRunner.

 

[kylerlaird]

I received the Kong this morning and immediately got it on the stand. 2old nailed it; I measured the front fork width at 134mm inside, 146mm outside. 36 spokes.

The bottom bracket is 100mm wide.

I'm on the hunt for components...