Things You'll Need:
- Hack saw
- Vise grips
- Two bicycles from which to make tandem
- Brazer
- Mountain bike forks
- Two large, 40 teeth, chainrings (must be same size)
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Step 1
Choose bikes from which you wish to make your tandem bicycle. Something middle-of-the-road would be best, as very inexpensive bikes will not be strong enough, and the very high-end bikes will have frames that are thicker at the ends. Bikes with a thicker fork work best.
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Step 2
Plan your bike construction by taking into account the riders. If one is larger, that rider should have the larger of the two bikes. Make the larger bike the front bike of the tandem.
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Step 3
Use hack saw to cut through the front half of the rear's head tube, and cut the front seat stays from the seat tube and the rear drop out or fork end.
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Step 4
Sand and file the paint down until bare metal is exposed at the cut ends.
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Step 5
Bend the front chain stays up and in, and then file the dropout's surfaces to ensure they're a good fit against the lower portion of the rear down tube. Doing this step properly is extremely important as it can affect the alignment of the finished tandem bicycle.
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Step 6
Fit the frames roughly together and clamp them in place with vise grips or clamps. Fit the rear frame's head tube around the front frame's seat tube. Make certain the drop out is pressing lightly against the down tube.
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Step 7
Install wheels to check the height of the wheel brackets from the ground. They should be anywhere from 11 to 11 1/4 inches high. Consider using mountain bike wheels instead of street bike wheels.
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Step 8
Check and double check the alignment of the bikes. This step is critical.
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Step 9
Braze the frames together. Only an experienced welder should undertake this portion of the project.
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Step 10
Install cantilever brakes on the front and rear bikes. This helps to stop the resulting heavier bike more easily.
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Step 11
Set up two chains. One connects the crankset to the rear wheel, the other links the bottom brackets together. These can be installed on the right side of the bicycle.
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Step 12
Make certain your chainrings are the same size. Having larger chainrings (40 teeth or so) are helpful as it helps there to be less stress on the chain and the frame.
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Step 13
Use old rear dérailleurs to help adjust the tension of the chain. You may mount these where convenient on the frame, and line them up with the synch chainrings.
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Step 14
Attach a handlebar stem that's 1 inch in diameter for the seatpost stem on the rear bike.
