boyntonstu
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- May 1, 2008
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This video shows a way to mount the engine behind the seat.
If you have a motorized 20, I am interested in how you mounted your engine.
I love 20" wheels. I ride a 5 speed mountain bike with raised seat and extension raised handlebars every day for exercise. I am 76 and I have been clocked at 18 MPH over a short distance.
Up to 33 MPH a 20" wheel is equal or faster than bigger wheeled bikes.
The wheel size on the bike used to set the world speed record on an upright bike was 18 inches. Small wheels usually require fewer spokes to achieve the same stability as the common 26 to 28 inch wheels, and fewer spokes generate less turbulence drag than larger wheels, leading to higher speeds. As pointed out by Alexi Grewal, 1984 Olympic road race gold medalist, a small wheel is more efficient than a large wheel in speeds up to 16 mph. In speeds between 16 and 33 mph, small and large wheels are equally efficient. Only in speeds faster than 33 mph is a large wheel preferable, Grewal says.
20" bikes are also more nimble and stronger as well.
AFAIK The only disadvantage is that 20" bike are harder to ride with no hands.
Surprisingly, there is more pedal to wheel clearance.
A 20" stores in a small space and can fit into many car trunks.
I want both a pedal and a motorized bike.
I am willing to trade my Honda-GX31 custom recumbent for a motorized 20".
http://www.motoredbikes.com/showthread.php?10689-Honda-GX-31-Trike
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