June 27th, 2012
I finally recovered enough from Gunnar’s visit to get up to Grant’s Tomb and take some proper portraits of this little rig. Getting it there was a bit of an obstacle. Too small to ride. Too big to go in the basket of the nose bike. Too short bend over and push that whole way. No midget to ride it for me.
I had to haul out the xtracycle, the only bike I have left from the original fleet that hasn’t been replaced all these years later.
I guess the next chance I get to take time away from customer bikes to do some *cough* R&D I’ll have to work on some sort of a long bike!
So. It’s a 1×9 MTB with 20″ wheels. My brother and I thought we might be able to get away with 24″ wheels until we realized that if we scaled that up the bike would be the equivalent of a 6′ rider on a 36er (which, as cool as it is.. oh never mind. It’s absurd). The main tubes are all Zona double butted seat tubes. Columbus makes one particular externally butted MTB seat tube that has a short enough thin section that it worked. Barely.
The chainstays are 19mm round seatstays, chopped up and custom bent to make room for the tire. Lowmount internal disk tab because I had one around. Since this bike won’t ever get a rack or fenders, there’s little advantage to it. Then again. If he ends up riding it to school a rack might not be a terrible idea! Rear 140 rotor and front 160. (double disk brakes on a bike that small!!? for a rider that small?? Um. yeah.)
Cranks were a bit of an issue. There’s really nothing out there that I could find that’s appropriately short for small riders. I think that’s part of the reason that short riders always look a little silly on bikes.. To have the seat low enough that they can reach the bottom of the pedal stroke with cranks that are too long, at the top of the pedal stroke they’re kneeing themselves in the chin. So I sniped a pair of Sugino RDs from one of the lesser used bikes around and re-drilled and tapped them at 130mm. Making sure that the pedal spindles and BB spindle were parallel was the main trick. The fixturing was pretty cute. They’re still a little long (if you can believe it) by some sort of half assed calculation that I made, but he’ll grow into them fast.