ShortHopper gets fired up again

July 2, 2010 · 2 comments

This project started back in April. I’m getting it fired up again. The original post can be seen here.

The idea behind this electric bike is multi-transport mobility. What this means is the bike is small and light enough that it can be transported in a car or train relatively easily and be a comfortable enough to enjoy riding at the destination. It will have lower range to keep the battery weight down and make it easier to lift. The bike could also be used for short trips to the store or around the neighborhood.

It will have 20” wheels with collapsible bars and seat. It will eventually fold but maybe not for this version. Since the range will be limited, the battery weight can be kept to a minimum. This will make the eBike easier to lift and move by hand.

The first build will be a prototype so I’m saving time by chopping an existing 26” frame and only fabricating what I need. The rear triangle is the only section I can reuse so the rest of the frame will be chopped and redone including the fork.

The fork is chopped and the dropouts are brazed in. The photo shows the fork in the fixture I had to design. You can read about it here.

Once the fork was brazed I was able to finish the full size drawing that will be used to lay out the tubes for mitering and brazing.

The donor frame has been chopped. Now I have to clean up the tubes to get them mitered and ready to fillet braze to match the drawing.

What do you think about this idea? Feel free to leave a comment, I’d like to hear. Is this a bike that you would use? What would you do differently?

As a side note I want to reiterate one of the underlying themes of this site. It’s not just about electric bikes and everything related; it’s also about how to build quality electric bikes from scratch on a budget. Expensive machines and fixtures aren’t needed to build a quality bike. Watch me learn how to do this. Leave comments and we can learn together.

{ 2 comments… read them below or add one }

1 danr July 20, 2010 at 7:44 pm

hey woodard – how did you strip the paint off the rear triangle?

2 Dan July 21, 2010 at 5:30 am

I’m still in the process of doing that. It has this thick silver paint on it so it might look stripped but isn’t. For the other tubes I started with an angle grinder with a purple abrasive pad followed by 80 grit sandpaper. It’s a pain. I’ve been thinking about getting a sand blaster that uses walnut shells or something like that to make it easier in the future. However, I’m to the point where I want to start building with fresh tubes only. The next bike I have planned will be from scratch and won’t use a donor frame. Chopping frames is cheap and educational but labor intensive.

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