A new adventure in e-bike building: Resto-Mod Mongoose Motocross

So the kid was turning twelve in the early part of July and we had been wanting him to have an ebike so he can keep up on our family e-bike rides.

Before e-bikes were so popular, you could buy this at department stores!

The Mongoose CX450 was a pretty cool bike - 15mph, 18 mile range, full suspension, front disc brake - sweet!

After looking around for a bit (during a time when almost no bikes were available for purchase) we decided it was time to build one. A few years back I bought a Mongoose CX450 that had been stripped of its electric drivetrain. So I pulled it out of storage and got to work.

Not our bike, but identical (I didn't take a before pic)

    My first attempt at getting it together was to add a brushed motor like the original setup for the bike but I struggled to come up with a suitable bracket to hold the motor. Being a man with a welder and welding skills would have made it possible, but that's not me these days.

So I came up with a Plan B - a brushless hub motor kit. Finding a 20" hub motor in a hurry is not so easy, but I was excited to find that ebikeling received a big shipment that included a very powerful 20" kit. Good prices and free shipping from Illinois - nice!

The conversion kit - 20", 1200 watt, 48 volt

At 1200 watts, the kit would be way too powerful for an e-bike beginner, especially one with the self-restraint of most 12-years-olds, so I also purchased the a hop-down part. 

The hop-down part - 36 volt, 500 watt, waterproof  controller

Going to the less powerful controller required changing some parameters on the LCD control panel, but that was pretty easy with the help of some online instructions. So now it's an 18mph bike with five levels of pedal assist - not a 30mph bike. (Don't tell the kid!)

The 1200 watt controller that's left over - my wife has dibs on this one.

The home-built battery from the Electron Klunker

The two hardest parts of the conversion were figuring out where to place everything and figuring out how to maintain a single-speed chainline on a motor intended for a 7-speed sprocket. (The answer came from this Endless-Sphere thread: Mounting Two Freewheels on one rear wheel hub. If you have questions about building your own e-bike, you will find most answers on the Sphere.)

And it all came together to make this:

The Mongoose lives again!

This new version has some big upgrades from the original. The battery went from 24 volts of lead acid to 36 volts of lithium-ion. The bike now has pedal assist, a rear hub motor, and an LCD display with all kinds of good information and programming options. It's faster and a lot more efficient. (And the kid loves it!)

For those of you who want to see  CX450s with hop-UP parts, there are several on Endless-Sphere.

So that's about it for this one. May you be well, may you know peace in the midst of division, and may the wind in your face be a pleasant one!