Archive for June, 2009


Converting a Children’s Bike to a Folder

Sunday, June 21st, 2009

After looking at some tiny folding bikes like the Strida, I decided to spend an afternoon creating my own tiny folding bike. I had a 16″ wheeled kids bike from a garage sale. I figured all it needed was a heavy duty door hinge in the middle to fold in half and some seat and steering extentions.


The bike is a bit “springy” thanks to its old school thin walled steel construction


The biggest door hinge I could find

I have to give myself credit for the quality of work I did. I prepped all joints very well and the welding was of high quality. If only I had done some measurements before I got the tools out…

I welded a pipe on to the original seat tube to extend it. I ground the weld down, sanded it, and painted it all black. I also created a cool extention for the steering. I took the original handle bar clamp, which was designed to clamp a horizontal tube, cut it off, and welded it back on turned 90 degrees to clamp a vertical tube. I then welded another clamp in the usual orientation to a piece of pipe which I then stuck into vertical clamp. I placed the original handlebars into this extended tube.

The hinge was a bastard to weld on, and I create a strange jig to hold it all together while I welded, utilizing an old piece of furniture and the garage’s ceiling joists. I used the biggest door hinge I could find.

Then I decided to go for a ride. I was slightly alarmed when I got on the seat. The children’s seat post is maybe 3/4″ OD. When it is a foot long, it doesn’t flex much. But when it’s been extended by another two feet, it suddenly gets very springy. Banishing all fear of my weld breaking and a seat post violating my most prized organs, I set off down the driveway. The short wheelbase was a bit… “nervous”. I had a hard time tracking in a straight line. This drunken weaving might have been ok if the pedal to ground clearance was not so low, and not decreasing like it was because the hinge was bending apart. My oscillations became so wild that the pedals started to drag on the concrete. By the time I reached the end of the driveway, with neighbors looking at me like a madman, I was ready to give up. The bike took care of that however by throwing the chain. I was unceremoniously dumped into the street.

I remembered Billy Bob Thornton in Bad Santa. “Well, they can’t all be winners kid…”

Maker Faire 2009

Friday, June 5th, 2009

HybridMojo was located in Bike Town at the 2009 Maker Faire in San Mateo.  Our booth included not only a few electric bicycles, but educational information on sustainability, basic ev components, and how to build bicycles.  The carnival themed test of strength pedal generator from the Google I/O Developer conference was back once again, this time with the reliable MY1018 motor.

The fair organizers put an entrance right nearby us, so we got quite a bit of traffic.  The upgraded booth probably helped too, as it was more elaborate than any in sight.  And amusingly for us, we had debated how to hang our bright orange banner so we clipped it to the ends of two 10 foot sections of EMT.  This sign became a meeting place of sorts, with folks on cell phones milling about trying to meet up with friends using the sign as a landmark.

Last year, everyone wanted to know max speed and range so we created information sheets that hung off the bikes.  This year, by far the most common questions were whether the bikes have “regen” and why the tandem is powered by Makita batteries– so we’ll be updating the website and information sheets accordingly.

Many thanks to Sherry and Bridgette and the rest of the crew who put the show on.  Great time as always.  And thanks to our crew– Ben, Sheila, Victor, and Mike!

090530 Maker Faire 2009090530 Maker Faire 200949 pictures Google Maps Location
San Mateo Expo Center, San Mateo, CA
May 30, 2009