I made one and hahahaha watch for falling parts is so true. In doing maintenance, trouble shooting and mods near to loose screws, bolt and the like are the norm on the two Rads I have experience with. For instance the back axle bolt came off super easy and the bottom bracket was also super easy to unscrew as well as the screws holding the battery, controller in the frame. I went through the whole bike giving a light lighten after finding so many loose or just barely tightened enough bolts and screws. They are build in China. Now,,, with that said it is important to keep in mind that non professional mechanics have a tendency to over tighten, I did, so try not to do that. Sourcing that locking washer: Few years back, I saw some on the Walmart site but ended making my own. I lost one on an old peddle bike and it was surprising easy to put a washer in my vice grip and hand saw two places enough to bend it in so it will fit in the grove on the frame. Would suck to have your rear wheel fall off.