New recumbent bike.

Here is my recumbent bike project, finished at last. It’s taken quite a while to finish this off due to this dam PMR which is affecting my wrists/elbows/shoulders /neck so, as I can’t ride my MTB anymore I decided to build another recumbent two wheeler. Most of the bike parts I scavenged from a recumbent trike I built about 10 years ago, the stripped trike frame now hangs from the shed roof, a rather dusty and forlorn sight now.

The rear wheel stayed basically the same except for the axle I had to shorten slightly complements of a slight build mistake on the rear forks: I tend to measure once and cut and weld twice as opposed to the more common approach - I’m different what can I say. The front wheel was made up using the spokes and rim from the trike but laced to a standard front bicycle hub I had lying around..

For a bottom bracket I turned a 35mm x 24TPI internal thread on piece of 38mm tube I had lying around, LH thread on one side and RH thread on the other. Unfortunately the bottom bracket warped a little when I welded it to the frame but, judicious use of a panel hammer and running a threaded bearing cup in and out a few dozen times freed up the thread again..

From the same stock I turned up and threaded a half bracket for the intermediate cassette and welded it to the frame. The internal thread on the older cassettes is the same thread as the bottom bracket bearing cups so a bearing cup was screwed into the cassette and the cassette screwed into the half bracket The intermediate cluster gives another four ranges handled by a modded front derailleur I mounted under the seat, Shifting is handled via an extension thumb tab welded to the modded derailleur.

The headstock I turned up from a solid lump of 38mm stock bored to take standard bearing cups. As the boom and bike frame are welded front and rear of the headstock and the headstock takes most of the bike and riders weight the middle section of the headstock I left fairly thick so It wouldn’t warp or bend.

Drop bars sit atop a 450mm riser which slips inside a modded BMX fork. As the handlebar riser is quite long I had to clamp it from the bottom of the fork using a standard riser slash clamp and a short 8mm allen head screw.

Brakes are simple side pulls and not very effective. I turned up a couple of nylon bushes for a pair of old stem mount shifters I had, welded backing plates with cable mounts to the handlebars and routed all cables through cable tidies I turned up and welded to the frame to keep things neat.

Front derailleur is GSX, and the rear is Deore, both quite old and way past their prime. Crankset is 52/36 from memory and the rear cassette is a 13-26 5 speed with an intermediate four range cluster in the middle. Due to the 20” rear wheel I had to swap and change cogs on the intermediate cluster to gear everything up a little. This set up gives me a slightly lower range than my MTB and a range slightly higher than the same bike. I mounted a couple of pulleys atop the boom for chain routing and also mounted a derailleur long cage in front for front chain tensioning. All up I think there are 2 ½ chains. The bike weighs 14kgs, the same as my MTB.

The frame is made from 30mm x 1.5mm RHS duragal, that‘s all I had to hand otherwise I would have used black.. Headstock is set at 70 degrees and wheel offset at 45mm, unfortunately the trail isn’t optimal making wheel flop more noticeable than I’d like and the steering is rather responsive. When I get around to it I’ll increase the wheel offset by another 10mm, that should give me less wheel flop and make the bike a little steadier at speed..

Seat height is 450mm and bottom bracket height is 600. Seat back angle is 45 degrees so weight is evenly distributed on the back and behind. Incredibly comfortable, sort of like sitting in a recliner..