Robs Stupid Recumbent Page


This is Robs Stupid Recumbent Page. It is Stupid.

Early 2001 I was talking with my dad, and he said he was planning on buying a recumbent bike. Recumbents are just like regular bicycles, except you sit more towards your back, and pedals are out in front of you. They wanted ridiculous prices for the bikes, so we decided to build one ourselves

Bike turned out really funky looking, and pretty hard to get used to, but it works and is pretty efficient

27+ mph in the first trials

A little adjustment to the steering, and some paint, a million times better. Now all it needs a real seat

A really comfy seat, just like riding an easy chair now.

Late 2001 In the last 6 months, my dad has put over 2000 miles on the bicycle we built, wow. I decided to build me one. There were several things wrong with the old one that I will try to remedy this time, frame was too flexible, too heavy, steering too touchy, not very stable, and the gearing was too low for fast cruising, and too high for steep hills.

The new design has a much shorter wheelbase with a 2.5" thin wall tubing main frame, which is lighter and much more rigid than the gas pipe we made the old one from. I stuck with a fairly standard steering design for mine which is much less sensitive than my dads. After the first couple runs up and down the street, it is very stable.

The front sprocket cluster has 3 gears, the rear has 7, like a normal 21 speed. What makes it special is that there is a 6 gear middle cluster that provides 5 ranges of overdrive, with a range of 1.12 to 2.0. It provides the overdrive by having the front chain drive 1 of the 5 lower gears (14-25 teeth) in the 6 gear cluster, and the largest gear (28 teeth), drives the rear chain. When the front chain is driving the 14 tooth sprocket, the rear chain spins twice as fast as the front chain.

The 21 speeds normally provide a range of 25-92 inches on a 27 inch bike, but the same gears on a 20 inch provide a range of 18-68 inches. With a minimum overdrive of 1.12 on a 20 inch gives a range of 21-76, even lower than the lowest range on the standard 27 inch. With the overdrive shifted to the 2.0 maximum, it has a range of 38-140, much higher than the 27 inch. So overall the new bike has a gearing range of 21-140 inches, which should be low enough for all but the steepest hills and comfortable to pedal at sustained high speeds. As a comparison, the first one my dad and I made has a range of 39-102, so the new one goes about twice as low, and almost 1 and a half times higher.

New recumbent, 105 speeds. It is fast and stable. It doesnt look like it, but it is comfortable too, even though I havent put the padding on the seat yet

Its got paint, but more importantly padding on the seat

Apr 17, 2004 The new recumbent has proven to be much more stable than the last one. It has about 1000 miles on it so far. Just for fun, we installed a 40cc airplane motor on it with a 20 inch propeller.

Stupid video of bike going down the street (2.3MB)

Apr 18, 2004 Having the motor in the front was kinda awesome, but the propeller would blow high speed oily exhaust in your face. Decided to try putting it on the back to keep the smoke out of the drivers face.

Stupid Video Going Faster with Rear Prop drive (1.9MB)

Having the propeller in the back actually made it go much faster. Wouldnt have thought so, maybe partially cause Im stupid, but who would have guessed that rear wheel (prop) drive would be better?

Bike goes 31.3 mph!

Later The 40cc 2 stroke model airplane motor wore out pretty quick, so we found a 50cc 4 stroke motor and attached a few different propellers. I dont reacll if the best/final size was a 22 inch or a 24 inch, but either way, 50mph on a bicycle is REALLY scary with no suspension and fairly woosy brakes.