Electric Mountainboard Build Part 7: First Ride and Future Improvements

The board is now complete! All that's left to do is test it and go out for a ride!

For the previous part, click here!

First Ride

The first thing I notice stepping on the board is that bindings feel very strange. I had to do quite a bit of fiddling to get comfortable, and even after a lot of fiddling, my rear foot kept slipping out. I'll need to spend some time on it to get it right.

The board feels a lot lighter strapped onto my feet compared to lifting it with my hands. Jumping in place wasn't as bad as I had thought for all the added extra weight. Landing was fine, none of the enclosures were coming loose, and the motor mounts seemed solid. 

First tentative stationary air

The first takeoff was extremely tentative and slow. I wasn't sure what the torque curve was, so I tried moving the thumbwheel as slow as possible. The remote was still in UART mode, so there was a considerable deadzone before anything actually happened. Once I reached the break point, it slowly rolled forward. It felt basically like starting from the Wowgo 2S, a smooth, predictable acceleration from a standstill. There wasn't any cogging, and was a lot smoother than what it had looked like on the bench, thanks to me being on it. I got it to around 4-5mph, getting a feel for the pneumatic tires and channel trucks, as it was my very first time taking the board out.

Carving with the board felt simultaneously familiar yet foreign at low speeds. It felt most closely to a RKP top mount board, but required quite a bit of leverage to turn, possibly a combination of harder trucks and the wide track. I found myself relying on the front bindings a fair bit. Riding on pavement was super smooth thanks to the pneumatic tires, and with my weight on it, I didn't encounter the vibrations that I got on the bench. 

The parking lot had a small medium grade hill to it, which I used to test the brakes. Usually on a regular longboard, gravity will get me to around 16mph by the end of the hill. The mountainboard barely accelerated when going down it. It also meant a good time to test brakes. I gingerly applied pressure to the thumbwheel, and after the dead zone, it started slowing down smoothly. I then decided to put a little more pressure, and it started slowing down at an alarming rate. Having come from the Wowgo 2S with Hobbywing ESC tuned for smoothness, I was surprised at the immediateness of the brakes. On top of that, the rubber tires grip the road surface, unlike the Wowgo which would lock up and start sliding. That will take some getting used to so I don't fall forward. 

After a few slow laps getting to know the board, I got brave enough to try a little more than minimal throttle. I moved the thumbwheel a little bit and it became a metaphorical rocket. The motors kick in immediately, and thanks to the low gearing, it pushes you forward with a wall of energy. I didn't even make it to half throttle before bringing it back down. It's a very different feeling where you become the limiting factor, not the board. Releasing the throttle also highlighted another difference from hubs - there is a significant jerk when it transitions and cuts power. I will need to be more careful backing off the throttle in the future, or set the negative ramping slightly longer. At higher speeds, the trucks loosen up considerably, and carving becomes much more natural and flowing.

Another thing I noticed is the noise. I knew going in that chain drive would be louder than other drive systems, but man is it loud. Part of that is attributed to the motors - they run at higher RPMs at lower speeds thanks to the gearing, and thus scream earlier. However, the chain imparts a metallic zing that almost sounds a bit like a chainsaw. All in all, it's a distinctive sound that can easily be heard a hundred feet away. There is no stealth with this board.

After doing a few loops around the parking lot, it was then time to try out off road performance. I made a detour to an empty playing field, and turned into the grass. The 8" wheels made it almost effortless, a little bumpy as expected, but it had no troubles going through. However, I ran into problems trying to turn in the grass. Thanks to the tight trucks in the back to reduce bite, the rear wheel was constantly lifting during a turn and spinning way too fast, thanks to a lack of traction control. I will need to loosen the rear a bit and turn traction control on before I'm comfortable off road with it. 

Future Improvements

After the ride, there were a few things I would like to modify. The first one is to tune the controller so it isn't as sensitive. I think the best way to do this would be to create different profiles to limit power. PPM mode also gives a little more adjustability, so it will be all PPM in the future. 

To solve for the constant rear wheel lift off road, I will be loosening the trucks back to their original position. While this introduces bite, a bit of bite is safer than a wheel losing traction. In addition, I am turning on traction control so the lifted wheel doesn't freespin. 

Now that I got Bluetooth working, it should be fairly straightforward to set speed profiles. I am thinking about setting three main profiles - one beginner/demo profile, one mellow profile where speed is unlimited but current is capped for smoother starts, and an unlimited mode where both current and speed are unlimited. I would use the mellow profile for road use most of the time, while I would switch to unlimited if I go off road. The beginner profile is self explanatory, and also caps speed. 

And that about wraps it up for the build itself! I will do a final summary post, and future additions to the board will be put in as separate updates. 

For the final part, click here!