Build a long-wheelbase low racer recumbent bicycle

Step 2 Slice off the rear triangle

The idea here is to remove most of the rear triangle of the donor bike while leaving the bottom bracket shell attached to the front down tube. Before you cut, measure the distance of the bottom bracket to the ground when the bike is upright and the tires are inflated and save this measurement. You will need it when you weld the new frame together. It is important for getting the front wheel at the proper angle.

Use your hacksaw to remove the seat stays from the seat tube while keeping as much seat stay material as you can. Cut the chain stays as close as you can to the bottom bracket shell. Cut the seat tube from the bottom bracket shell leaving enough attached to the bottom bracket shell for the front derailler to mount plus about 2". Grind the remaining seat stay material from the bottom bracket shell - make it look nice.

Don't worry if you end up with big holes in the bottom bracket shell from the chain stays. Just try to keep all the metal straight so you will be able to re-thread the bottom bracket back in later.