Step 1: Materials
What we used :
- arc welder
- corresponding safety gear
- a pair of non rusted brains
- 2 scrap bikes
- a differential, probably from some car
- scrap metal bars and tubing
- bright yellow painting
- a cool motorbike steering bar
- cool strips cut from inner tubes
Step 2: Starting the Assembly
We first prepared the bikes, by removing useless parts, brakes, cables...
the differential was then disassembled, to get the 4 gears and one center axle.
Step 3: Welding the Gears .
We used the two big gears welded to the steering axles. One at the top of the fork (over the head tube), on the big bike, the other at the bottom of the small bike, under the head tube .
To make sure they were welded level, we clamped them and positionned them carefully (but still just eyeballing).
Step 4: Assembling the Elements Into a Single Frame .
You also have to separate the gears from a precise distance, based upon the size of the two smaller gears.
To add in the two smaller gears, we used the bar from the original differential, at the end of which we welded a washer to prevent the wild gear from unleashing itself. The axle was then extended with a small tube and fitted between the two black metal bars. So the axle is part of the bike structure, and can't move, but the gears can turn freely around the axle. see video :
Step 5: Finishing the Frame
Adding a tube part, cut from the steering bar of the mountainbike, and a motorbike super cool steering bar to the final product, now close to be finished. A bit of grinding and welding here.
Also, unrusting the chain by bathing it in WD40 and unjamming each link with two pairs of pliers.
Step 6: Paint Job
Take off all pedals and cables, derailleur, seatpost. Protect with masking tape and paper all that can't be removed and that you want to keep clean . Ungrease and sand all the surfaces you want to paint . Choose a smiling color at your local paint shop. Spray until the bottle is empty . Go back to the shop to buy more paint. Yellow is too light, we needed several coats to get the bike really colourful. (3 or 4 , in our case).
lock yourself and swallow the key so you can't touch the paint during 24 hours . We skipped this step and got fingerprints all over the bike.
reassemble the lacking parts quoted above, add two wheels, an you're off.