During the 1970's Bike Boom, millions of Americans bought ten-speed bikes. Many people rode them only a few times, or once. Some didn't like the dropped handlebars or small "hard" seats; others couldn't quite get the hang of shifting derailleurs. Given the fragile nature of most derailleurs of the time, the results weren't pretty, especially when the derailleurs were out of adjustment or the rider tried to shift while standing still or under pressure.
Then there were the engineering types and tinkerers who look at any mechanical device and think "There must be a better way." And, finally, there were lots of newly-minted lawyers with too much time on their hands who saw all sorts of potential lawsuits lurking. (Some of them helped to found the CPSC.)
One of the best-remembered attempts to correct the "deficiencies" of derailleur gearing was Shimano's Front Freewheeling system. Basically, it incorporated a freewheel-like mechanism between the chainrings and crank so that the chainrings spun as long as the wheels were spinning. This allowed riders to shift without pedaling.
Some people who were accustomed to internally-geared hubs (like Sturmey-Archer three-speeds) liked this new innovation, which is probably the reason why it developed something of a following in Germany, where many people still cycled for transportation but few were accustomed to derailleurs. However, the FF system was heavy and complicated, and was equipped only on entry-level bikes.
Another attempt to bypass the idiosyncrasies of derailleurs and multiple rear sprockets is all but forgotten today. But it was interesting in its own way.
Before its foray into the bicycle business, Tokheim had about seven decades' worth of experience in manufacturing fuel dispensers and pumps, and equipment for payment terminals and retail automation systems. So, if you've ever owned or managed a gas station, you've seen or used Tokheim equipment.
Like a few other American companies, Tokheim thought the Bike Boom was an opening for a new profitable market. And, like those other companies (including, of all companies, Beatrice Foods!), they thought they could make bike parts and accessories even though they had absolutely no experience with them--or, it could seem, cycling.
Then again, Tokheim's experience with pumps and other kinds of machinery had, it would seem, at least some applicability to designing and manufacturing a bicycle gearing system. It was at least somewhat in evidence in their "Gear Maker" system.
When drivetrains with derailleurs are shifted to their extreme positions (small chainring with the smallest rear cog or largest chainring with largest rear cog), severe chainline angles can result. This usually results in noisier running; in worse cases, it leads to premature chain and cog wear. In the worst cases (especially with an inexperienced and unskilled rider), the chain can be thrown off the cogs and into the wheels or get stuck between the chainrings and chainstay.
Most cyclists learned, in time, not to shift into the extreme gear positions--or to do so carefully. However, some could never get past that first experience of a missed shift. Or, if they had no previous experience with multi-cog systems, they were intimidated.
That is the "need" the Tokheim system was intended to meet. Imagine an old-fashioned Ferris wheel: the kind with a "spider" that rotates around an axle at its center and "cars" or "gondolas" at the end of each arm. Those cars and arms are in fixed positions and will always reach the same height at the peak of their rotation.
Now imagine that between those arms, there are other arms, except that these arms are expandable and retractable. Thus, the Ferris wheel operator could expand the diameter (and height) of the wheel for more adventurous customers. But the cars of those expanded and contracted cars would rotate in the same plane as the cars on arms with fixed lengths.
The gear in the "gear maker" was like that Ferris wheel. It was operated with a twist-grip shifter. When the shifter was in its "high" position (slackened cable), the chain ran on the smallest gear, which was fixed to the axle. Shifting down made an interposer arm push a series of bars out successively. At the end of each bar were teeth like those of a typical rear sprocket. The chain ran on a larger sprocket something like the "skip tooth" cogs found on some 1970s freewheels. A tensioner--basically a derailleur cage and pulleys--took up chain slack.
For a time, the Tokheim system came as standard equipment on a few Huffy and Murray bikes. I never saw a bicycle sold in a bike shop that was equipped with the Tokheim system, and I don't know whether anyone ever retrofitted it to a bike. For that matter, I didn't know anyone who rode it, and only got to work on a couple of them, so I don't know how they performed in the "real world". However, as the gears were made of plastic, I suspect they wore fairly quickly. And, as Tokheim stopped making it around 1980 and, to my knowledge, never offered replacement parts (and because most of the bikes that came with them have long since ended up in landfills), I don't suspect that very many Tokheim Gear Makers are in use today. But, I think, they are interesting nonetheless.
Then there were the engineering types and tinkerers who look at any mechanical device and think "There must be a better way." And, finally, there were lots of newly-minted lawyers with too much time on their hands who saw all sorts of potential lawsuits lurking. (Some of them helped to found the CPSC.)
One of the best-remembered attempts to correct the "deficiencies" of derailleur gearing was Shimano's Front Freewheeling system. Basically, it incorporated a freewheel-like mechanism between the chainrings and crank so that the chainrings spun as long as the wheels were spinning. This allowed riders to shift without pedaling.
Some people who were accustomed to internally-geared hubs (like Sturmey-Archer three-speeds) liked this new innovation, which is probably the reason why it developed something of a following in Germany, where many people still cycled for transportation but few were accustomed to derailleurs. However, the FF system was heavy and complicated, and was equipped only on entry-level bikes.
Another attempt to bypass the idiosyncrasies of derailleurs and multiple rear sprockets is all but forgotten today. But it was interesting in its own way.
Before its foray into the bicycle business, Tokheim had about seven decades' worth of experience in manufacturing fuel dispensers and pumps, and equipment for payment terminals and retail automation systems. So, if you've ever owned or managed a gas station, you've seen or used Tokheim equipment.
Like a few other American companies, Tokheim thought the Bike Boom was an opening for a new profitable market. And, like those other companies (including, of all companies, Beatrice Foods!), they thought they could make bike parts and accessories even though they had absolutely no experience with them--or, it could seem, cycling.
Then again, Tokheim's experience with pumps and other kinds of machinery had, it would seem, at least some applicability to designing and manufacturing a bicycle gearing system. It was at least somewhat in evidence in their "Gear Maker" system.
 |
| The Tokheim Gear Maker |
When drivetrains with derailleurs are shifted to their extreme positions (small chainring with the smallest rear cog or largest chainring with largest rear cog), severe chainline angles can result. This usually results in noisier running; in worse cases, it leads to premature chain and cog wear. In the worst cases (especially with an inexperienced and unskilled rider), the chain can be thrown off the cogs and into the wheels or get stuck between the chainrings and chainstay.
Most cyclists learned, in time, not to shift into the extreme gear positions--or to do so carefully. However, some could never get past that first experience of a missed shift. Or, if they had no previous experience with multi-cog systems, they were intimidated.
That is the "need" the Tokheim system was intended to meet. Imagine an old-fashioned Ferris wheel: the kind with a "spider" that rotates around an axle at its center and "cars" or "gondolas" at the end of each arm. Those cars and arms are in fixed positions and will always reach the same height at the peak of their rotation.
Now imagine that between those arms, there are other arms, except that these arms are expandable and retractable. Thus, the Ferris wheel operator could expand the diameter (and height) of the wheel for more adventurous customers. But the cars of those expanded and contracted cars would rotate in the same plane as the cars on arms with fixed lengths.
The gear in the "gear maker" was like that Ferris wheel. It was operated with a twist-grip shifter. When the shifter was in its "high" position (slackened cable), the chain ran on the smallest gear, which was fixed to the axle. Shifting down made an interposer arm push a series of bars out successively. At the end of each bar were teeth like those of a typical rear sprocket. The chain ran on a larger sprocket something like the "skip tooth" cogs found on some 1970s freewheels. A tensioner--basically a derailleur cage and pulleys--took up chain slack.
For a time, the Tokheim system came as standard equipment on a few Huffy and Murray bikes. I never saw a bicycle sold in a bike shop that was equipped with the Tokheim system, and I don't know whether anyone ever retrofitted it to a bike. For that matter, I didn't know anyone who rode it, and only got to work on a couple of them, so I don't know how they performed in the "real world". However, as the gears were made of plastic, I suspect they wore fairly quickly. And, as Tokheim stopped making it around 1980 and, to my knowledge, never offered replacement parts (and because most of the bikes that came with them have long since ended up in landfills), I don't suspect that very many Tokheim Gear Makers are in use today. But, I think, they are interesting nonetheless.
