When it comes to bringing an idea to life it’s best to have both a sense of purpose, and an eagerness to apply whatever is on hand in order to get results. YouTube’s favorite Ukrainians [KREOSAN] are chock full of both in their journey to create this incredible DIY e-bike using an angle grinder with a friction interface to the rear wheel, and a horrifying battery pack made of cells salvaged from what the subtitles describe as “defective smartphone charging cases”.
What’s great to see is the methodical approach taken to creating the bike. [KREOSAN] began with an experiment consisting of putting a shaft on the angle grinder and seeing whether a friction interface between that shaft and the tire could be used to move the rear wheel effectively. After tweaking the size of the shaft, a metal clamp was fashioned to attach the grinder to the bike. The first test run simply involved a long extension cord. From there, they go on to solve small problems encountered along the way and end up with a simple clutch system and speed control.
The end result appears to work very well, but the best part is the pure joy (and sometimes concern) evident in the face of the test driver as he reaches high speeds on a homemade bike with a camera taped to his chest. Video is embedded below.
As [AussieJester] noted in the first page of his build log, most people’s idea of a “custom-made” electric bicycle involves strapping some electronics and a hub motor onto any off-the-shelf bike. He needed a bigger challenge, so he fabricated his own frame to build a stylish electric cruiser. This bike has a 2-speed transmission and a massive Turnigy 80-100 brushless outrunner motor, which pushes out a top speed of 45mph.
You may have noticed what look like training wheels in the picture above, and you’d be half-correct. [AussieJester] is a paraplegic, and needed to guarantee some stability both when transferring from his wheelchair and when coming to a stop. The best feature of this bike, however, is that these small wheels are retractable. A linear actuator lowers them for slower speeds and for mounting/dismounting, but picks them back off the ground once you are up to speed, maintaining a true 2-wheeled experience.
Stick around for a couple of videos after the break: a first-person POV showing just how quick this bike can move, and a demonstration of the actuators. Then check out another EV pioneer in the world of skateboarding.
A 48 volt power house pushes this mountain bike at speeds up to 30Mph. That’s a bit of a boost from many off the shelf E-bikes. [Jennifer Holt] wanted speed, and to retain the off road capabilities of her bike, so she made a custom one. As you can see in the video, this thing gets going fast and hills are no problem. She says that it will toss you off if you slam the throttle, and we believe her. We know some of you will insist on chiding her because she’s not wearing a helmet in those videos. She did manage to break her elbow offroading in the video after the break. That part is edited out though.