Stewart Warner got their start back in 1912 when the Stewart & Clark company, founded by John K. Stewart, bought the Warner Instrument Company and changed their name to Stewart-Warner Corporation. In the beginning they made speedometers for the Ford Model T. and then went on to make Stewart Warner Bicycle Speedometers out of their Chicago manufacturing plant.
Bicycle speedometers or cyclometers as they are often called, tell the cyclist how fast they are going. Unlike most cyclometers today, vintage speedometers of the past didn’t require batteries, which made them some of the greenest technologies around. The display was pretty basic however, which only included speed and distance.
These vintage bicycle speedometers were green before green was cool. Not only that, but they were built to last, unlike so many products today.
How Old Bicycle Speedometers Work
Vintage speedometers use the measurement circumference of a bicycle tire to calculate the bike’s speed and distance by using the number of tire revolutions per minute. More revolutions equals faster speed and distance. What makes vintage speedometers unique compared to today’s speedometers, is they didn’t require batteries. Instead, they used a gearing mechanism housed in a sturdy cable to send the rotation speed up to the speedometer unit.
Housed in the Speedometer display is a magnet. As the wheel turns it starts to spin a magnet. The faster the magnet spins, the stronger the magnetic field becomes and the eddy fields become larger. This is what drives the speedometer needle to react and point to the various speeds. At a slower speed, there is less magnetic field generated and smaller eddy fields. Pretty neat.
These Stewart Warner Bicycle Speedometers are the perfect complement to any Vintage Schwinn Bicycle.
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