BUILD
NOTES
Run a mini electric “punk bike” faster (and funnier)
by powering it with a big, bad cordless drill.
The Drill Rod
BY RUSS BYRER
■ I HAVE A 25' CRUISING TUGBOAT IN FLORIDA,
and I wanted a small, lightweight ride that I could
keep onboard for making beer and ice runs when
I pull into a marina. After seeing a short segment on
TV about a cordless-drill-powered bike at a hardware convention, I decided to build my own.
Behold the result: the Drill Rod (Figure A).
Equipped with a 36-volt drill, this brute accelerates
from 0 to 10mph in just 2 seconds and is responsive
enough to do tricks like standing on its back wheel.
As for styling, it’s been said that when I’m on
my Drill Rod, I look like a circus bear on a tricycle
(duly note in Figure B). You will not attract potential
romantic partners when riding this. Trust me.
When I started the project, I contacted the
company that made the bike I saw on TV and asked
if they could just sell me the right-angle gearbox
that enables the center-mounted drill to drive the
rear wheel. But they refused; they would only sell
a finished bike.
I continued looking for ways to build my own.
At a flea market, I found a tiny battery-powered bike
for kids called the Electric Punk, made by Razor.
I bought it for $60 and took it home. With its small
battery and motor, I knew it was underpowered
for what I needed, and its 7" rear wheel looked too
small to support the weight of an adult.
On flat pavement, the Electric Punk only went
5mph, and it couldn’t even pull me up my driveway
slope. But its small frame was perfect for the project.
For the engine, I used a 36V Bosch Litheon drill,
which was the most powerful cordless I could find.
I bought it reconditioned through Amazon for $219.
I also found a nice, small right-angle gearbox (1: 1
ratio) made by Torque Transmission, model #RAB- 1,
which was rated at 1/3HP at the drill’s maximum
speed of 1,800rpm.
Beefing Up the Rear Wheel
I took the Electric Punk apart (Figure C) and went
to work. I stripped the plastic shells, the battery, the
motor, and the motor thumb trigger on the right
handlebar. I threw the useless little motor in the trash.
First I replaced the 7" rear wheel with a larger rear
wheel and sprocket assembly for the Razor Mini
Chopper, which takes a 9" tire. This would carry
weight more comfortably. I don’t know if this was
strictly necessary, but I knew I wanted it in order to
make the bike look cooler.
To fit the 9" wheel onto the bike, I needed to
relocate the axle farther back on the swing arm, so
I drilled new axle holes about ¾" behind the original
ones, and then moved the brake pads back to match
(Figure D, page 111).
A B
Photography by Russ Byrer (Fig. A); and courtesy of Russ Byrer (Fig. B)
108 Make: Volume 21
