Building a cut-down bike scooter, part 4

The scooter frame was complete and had been brushed free of grime, finish, and weld slag. All it needed was a deck to stand on. I started by experimenting with a skateboard-style wooden deck, but it seemed visually wrong and probably too prone to wear and breakage.

I liked and so didn't remove the Iron Horse crest from the steering tube.

I decided that what I really wanted was freewheel sprockets on the deck. I played with positioning some and liked how they looked, and liked that they articulated the theme of a cut-down bicycle.

My client was justifiably concerned about the sharp and jagged teeth of the sprockets chewing up the rider's ankles, though, and I had to find a way around that. But I decided to commit to the gears and welded them in place.

After some thought, I decided to cut sections out of a wheel rim and weld them in place on either side of the deck to define its edges and protect the rider from the sprockets. If I had arrived at that plan before welding on the sprockets, I would have placed the largest gear in the centre, at the widest part of the deck. But sometimes I have to make a stand and resolve the remaining problems later to move forward.

With everything welded down, the scooter was complete. The deck was wide, comfortable, and stable.

This is the completed commission. I was very happy with it and rode it around the neighbourhood for a while before giving it up to my client.

Nice ride!

Building a cut-down bike scooter, part 3

With the down tube wrapped around the front wheel and the top tube inverted and moved to the deck, the next step was to find a way to attach a rear wheel. I removed the front wheel from an abandoned child's bike, installed it in the rear dropouts, and positioned it to see how it would look.

I was pleased with the possibilities, and committed to it by cutting off the bottom bracket and what was left of the seat tube.

Positioned this way, it started to have a dragster sort of feel to it, which I liked. To get the chain stays level with the deck, I decided to bend them just at the edge of the wheel.

Again, I cut wedges out of the tubes so that they would bend easily and precisely. I had previously removed material from the dropouts so that I would be able to bend the seat stays down toward the deck, and you can see the missing sections here.

I placed the stays back into position for a final check before bending the stay assemblies closed.

I heated the dropouts where I wanted them to bend, to just shy of their melting point, and then gently closed the triangles.

With those assemblies completed, the whole frame was ready to weld together. The seat stays are inserted inside the top tube, and the chain stays spread outside it.

Here's the completed frame, with the tack welds completed and the rear triangles welded closed.

It was ridable in this state, and my hopes were realized -- it was way too much fun to ride. I did have to lock out the travel in the front shocks, though. Every time I gave a good kick the deck hit the ground. I drilled through the shocks and brazed in a section of bolt to keep them from compressing. The final steps were to brush the frame free of finish, complete the deck, and apply a few coats of wax to slow the rusting. At this stage, I still hadn't figured out how to make a deck to stand on.

Building a cut-down bike scooter, part 2

I decided that the deck of the scooter would be built on the top tube of the bicycle. Flipped upside down, the seat tube could extend upward to meet the down tube, which had been wrapped around the front wheel but didn't come close enough to the ground to meet the deck.

So, I separated the seat stays from the top tube.

The seat post sleeve and gusset would drag on the ground, so I removed them also.

Then, with some trial-and-error fitting, I decided where to cut the seat tube and separated it from the stays. The photo below shows the two sections of the bike that remained.

To join the inverted seat tube stub to the now-plumb end of the down tube, I decided to run the seat post through the seat tube and up into the down tube. I brushed the finish off the seat tube and drilled holes to allow for rosette welds, which would help join the seat post and tubes.

With the seat tube installed (forcibly, with a mallet) it was ready to weld.

It was a fussy business getting the alignment right, so that the deck was level and the correct height off the ground. When I was satisfied with it, I tack-welded it all together.

The remaining challenge was to modify the stays to hold a smaller wheel from a child's bike and tack the whole thing together, which I'll show in the next post.