My home-built tandem is done!

Well, at least mostly done. I have gone on a couple of short rides with my wife so far, and figured I'd share it with anyone who's interested.



I built this with left over and discarded parts, along with a few secondhand purchases such as the shifters.

I started with an old Centurion road bike frame and a Huffy (whoo-hoo!) mountain bike frame for the rear. I modeled the frame after a couple shown on Sheldon Brown's web site. I cut the front of the Huffy's head tube off, welded it to the seat tube of the front frame. Then I cut and bent the chain stays of the front frame to mate with the down tube of the rear frame and welded them. Since I went with 700c wheels, I also had to cut the rear brake mount off and re-position it. The front caliper had a long enough reach and didn't require a new fork or fabrication.

I didn't want to use an idler pulley so I ordered an eccentric bottom bracket from Nova Cycles (a frame builder supply), and machined it to fit in the rear bottom bracket shell. I split the rear bottom bracket shell, fabricated pinch bolts and welded them to it. Now the timing chain tension is adjustable just like a commercially built tandem.



The drivetrain is a single sided setup with 42 tooth timing chain rings and a double on the back crank; modeled after one shown on John Allen's site. I've ordered longer chainring bolts and spacers; I have them bolted together right now with hardware store stuff.



The shifters and front bar are 7 speed Shimano STI, $60 used, and I welded the mounts for the cable adjusters where the old downtube cable stop clamp went. The rear handlebar/stem is the one from the Huffy, welded to a seatpost clamp cut from another scrap frame.

Total cost so far has been about $150 for used shifters, cranks and chain wheels and a new chain. The road bike was a $10 flea market purchase originally, and the Huffy frame came from a scrap pile. Wheels, derailleurs, etc. came from the road bike. My goal is to ride it in the MS 150 ride in September with my wife.