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Recumbent bicycle
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Recumbent bicycle
A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position, and often called a human-powered vehicle or HPV, especially if it has an aerodynamic fairing. Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix of wheel sizes; overseat, underseat, or no-hands steering; and rear wheel or front wheel drive. A variant with three wheels is a recumbent tricycle, with four wheels a quadracycle.
Speed recumbents are generally faster than upright bicycles, but they were banned by the Union Cycliste Internationale (UCI) in 1934. Recumbent races and records are now overseen by the World Human Powered Vehicle Association (WHPVA), International Human Powered Vehicle Association (IHPVA) and World Recumbent Racing Association (WRRA).
Some recumbent riders may choose this type of design for ergonomic reasons: the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands. Others may choose a recumbent because some models also have an aerodynamic advantage; the reclined, legs-forward position of the rider's body presents a smaller frontal profile.
Recumbents can be categorized by their wheelbase, wheel sizes, steering system, faired or unfaired, and front-wheel or rear-wheel drive.
Long-wheelbase (LWB) models have the pedals located between the front and rear wheels; short (SWB) and medium-wheelbase (MWB) models have the pedals in front of the front wheel; compact long-wheelbase (CLWB) models have the pedals either very close to the front wheel or above it. Bikes with wheelbase less than 42 inches are classified as SWB, above 42 inches are MWB. Within these categories are variations, intermediate types, and even convertible designs (LWB to CLWB) –there is no "standard" recumbent.
The rear wheel of a recumbent is usually behind the rider and may be any size, from around 16 inches (410 mm) to the 700c (or 27 inches (690 mm) on some older models, as on upright road bikes of that time) of an upright racing cycle. The front wheel is commonly smaller than the rear, although a number of recumbents feature dual 26-inch (ISO 559), 650c (ISO 571), 700c (ISO 622), or even 29-by-4-inch (740 mm × 100 mm) oversize all-terrain tires. Given the smaller front wheel, loss of steering and control are somewhat more likely attempting sharp or quick changes of direction while crossing over patches of loose dirt, sand or pebbles.
Larger diameter wheels of the same type casing construction generally have lower rolling resistance but a higher profile leading to higher air resistance. High-racer aficionados also claim that they are more stable, and although it is easier to balance a bicycle with a higher center of mass, the wide variety of recumbent designs makes such generalizations unreliable. Another advantage of both wheels being the same size is that the bike requires only one size of inner tube.
One common arrangement is an ISO 559 (26-inch) rear wheel and an ISO 406 or ISO 451 (20-inch) front wheel. The small front wheel helps to keep the pedals and front wheel clear of each other, avoiding the problem on a medium wheelbase recumbents called "heel strike" (where the rider's heels catch the wheel in slow speed, small radius turns). Pedal extenders combined with a 20 inch front wheel eliminate any heel strike issue on MWB bikes.
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Recumbent bicycle AI simulator
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Recumbent bicycle
A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position, and often called a human-powered vehicle or HPV, especially if it has an aerodynamic fairing. Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix of wheel sizes; overseat, underseat, or no-hands steering; and rear wheel or front wheel drive. A variant with three wheels is a recumbent tricycle, with four wheels a quadracycle.
Speed recumbents are generally faster than upright bicycles, but they were banned by the Union Cycliste Internationale (UCI) in 1934. Recumbent races and records are now overseen by the World Human Powered Vehicle Association (WHPVA), International Human Powered Vehicle Association (IHPVA) and World Recumbent Racing Association (WRRA).
Some recumbent riders may choose this type of design for ergonomic reasons: the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands. Others may choose a recumbent because some models also have an aerodynamic advantage; the reclined, legs-forward position of the rider's body presents a smaller frontal profile.
Recumbents can be categorized by their wheelbase, wheel sizes, steering system, faired or unfaired, and front-wheel or rear-wheel drive.
Long-wheelbase (LWB) models have the pedals located between the front and rear wheels; short (SWB) and medium-wheelbase (MWB) models have the pedals in front of the front wheel; compact long-wheelbase (CLWB) models have the pedals either very close to the front wheel or above it. Bikes with wheelbase less than 42 inches are classified as SWB, above 42 inches are MWB. Within these categories are variations, intermediate types, and even convertible designs (LWB to CLWB) –there is no "standard" recumbent.
The rear wheel of a recumbent is usually behind the rider and may be any size, from around 16 inches (410 mm) to the 700c (or 27 inches (690 mm) on some older models, as on upright road bikes of that time) of an upright racing cycle. The front wheel is commonly smaller than the rear, although a number of recumbents feature dual 26-inch (ISO 559), 650c (ISO 571), 700c (ISO 622), or even 29-by-4-inch (740 mm × 100 mm) oversize all-terrain tires. Given the smaller front wheel, loss of steering and control are somewhat more likely attempting sharp or quick changes of direction while crossing over patches of loose dirt, sand or pebbles.
Larger diameter wheels of the same type casing construction generally have lower rolling resistance but a higher profile leading to higher air resistance. High-racer aficionados also claim that they are more stable, and although it is easier to balance a bicycle with a higher center of mass, the wide variety of recumbent designs makes such generalizations unreliable. Another advantage of both wheels being the same size is that the bike requires only one size of inner tube.
One common arrangement is an ISO 559 (26-inch) rear wheel and an ISO 406 or ISO 451 (20-inch) front wheel. The small front wheel helps to keep the pedals and front wheel clear of each other, avoiding the problem on a medium wheelbase recumbents called "heel strike" (where the rider's heels catch the wheel in slow speed, small radius turns). Pedal extenders combined with a 20 inch front wheel eliminate any heel strike issue on MWB bikes.
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