Bicycle Power

Bicycle power is one of the most efficient forms of mechanic energy transfer ever invented. Even sitting still, you can put it to work for you in multiple ways.


| January/February 1981



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This piston pump and rebuilt water tank, rescued from a hardware store's scrap pile, cost $20.


MOTHER EARTH NEWS STAFF

Without a question, humankind's most practical transportation achievement to date is the bicycle. In fact, a person on a cycle is nearly fire times as efficient as he or she is when walking. And, on the other end of the energy-in/energy-out scale, driving an automobile requires nearly 75 times as many calories as does pedaling a bicycle the same distance!

The spectacular efficiency of bicycles (10-speeds in particular) has led many tinkerers to put them to use doing stationary work. (The antecedents of such a practice include the treadle sewing machines, lathes, and sharpening wheels that our forebears used.)

So, in response to numerous requests from readers, MOTHER EARTH NEWS' research staff decided to develop its own variation on bicycle power. This issue's installment will describe how to put together a bicycle-based foot-power chassis, and how to use the pedal-produced energy to run a bicycle-powered water pump. In future issues we'll consider other applications for this basic unit from electrical generation to power-tool operation!

Framing the Frame

Quality 10-speed bikes are carefully designed and manufactured to make the best use of the power supplied by your legs. Therefore, if you want the most efficient pedal-energy device possible, start with a well-built cycle. Of course, that doesn't mean you need to spend several hundred dollars buying a brand-new lightweight racer: Many bargains (for our purposes) can be located in junk piles. (For example, we bought our Raleigh 10-speed from our local hardware store's scrap pile for $5.)

Once you have acquired this essential component, the construction of the foot-cranked powerplant is mostly a matter of providing the cycle's chassis with a stable platform. Start by detaching the wheels from both ends of the bike, and then loosen and remove the rim and spokes from the rear wheel hub. (To accomplish this task, you'll need to pull the tire and tube from the wheel rim, and unscrew each spoke using either a suitable spoke wrench or a screwdriver modified to slip into the spoke nipple.) Now, reinstall the rear hub and axle.

At this point we recommend that you remove the bicycle's front fork assembly. Though it is possible to attach a metal pipe base similar to ours directly to the fork legs (by using the old axle mounts), the wheel supports of most bicycles are designed to flex slightly to absorb road shock, and would provide a rather wobbly mount for your cycle-power unit.





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