Chris Froome shows off his new Jaguar Pinarello DogmaF8. (Photo: Getty Images)
YOU’VE GOT TO LOVE the burgeoning of human inventiveness. One invention leads to another, and before we know it, we have something that changes the world. Take the wheel. What a marvellous discovery. But the unknown person who conceived the axle really got it all rolling. Have a close look at the world around you and imagine what it would be like if there were no such thing …
After these primeval creations hit the world, it wasn’t long before we learned how to harness their power and augment human effort.
The first bicycle appeared in 19th-century Europe. It had a profound effect. The designer of the car itself owed an enormous debt to the human-powered version of popular transport. Ball bearings (another crucial development which helped the wheel rotate around the axle), chain-driven sprockets, pneumatic tyres, washers, tension-spoked wheels – all were borrowed by imaginative engineers and skilful metalworkers from the humble pedal-powered, single-track vehicle. Even the first aircraft owed much of its original design to the bicycle.
These days, the bicycle has many versions: mountain, touring, utility, racing, hybrid, cruiser bicycles, the BMX and many others. What makes these many functions possible is the gearing system. Variable gear ratios allow a cyclist to negotiate varied terrain and still maintain optimal pedalling speed.
When cycling downhill, a cyclist might use a high gear. On a flat road, a medium gear. And a low gear uphill, into strong winds or carrying a load. The principle is ingenious. In a lower gear, each turn of the pedal causes fewer rotations of the rear wheel, which enables more turns of the pedal with the same energy expenditure over the same distance. Higher gears allow riders to make fewer pedal turns to maintain their speed, by expending more effort for each turn.
Bike gears were simpler in 1947 Tour De France winner Jean Robic’s day. (Photo: Getty Images)
What allows for this variation is the bike’s derailleur system, which consists of a chain, multiple different-sized sprockets and a mechanism which shifts the chain from one sprocket to another. This system normally consists of two derailleurs, one at the front to select the chain ring and one at the back to select the sprocket. The former only has to move the chain side-to-side between the front chain rings, but it has to do this with the top, taut portion of the chain. It also needs to accommodate differences in chain ring size: some can have 53 teeth, some only 20. The latter takes up chain slack caused by moving to a smaller sprocket at the rear or to a smaller chain ring by the front derailleur, which is situated in the bottom, slack portion of the chain.
The derailleur gets its name because it “derails” the chain onto different sprockets.
Modern front and rear derailleurs typically consist of a moveable chain-guide operated by another wonderful invention, the Bowden cable, a rigid, yet flexible cable that transfers energy and enables the rider to shift gears. This advancement allowed the rider to operate a lever while still pedalling, and the alteration in its tension moved the chain from side-to- side. The cable is attributed to Sir Frank Bowden, who founded the Raleigh Cycling Company. However, this is in dispute, as another Bowden, Ernest Monnington Bowden (no relation), is believed to have patented the cable in 1896.
A French rider, Paul de Vivie, invented a two-speed rear derailleur in 1905. Until 1937, riders in the major Tours would have to dismount and change wheels as the terrain changed. That year, the derailleur system was introduced to the Tour de France. In 1949, Campagnolo introduced the Gran Sport, a superior version of the cable-operated “parallelogram” rear derailleurs.
In 1964, Suntour invented the slant-parallelogram rear derailleur, which resulted in easier shifting.
Today, Campagnolo, Shimano and SRAM are the three main manufacturers of derailleurs. Campagnolo only manufactures road-cycling derailleurs, while Shimano makes road and off-road. SRAM has specialised in derailleurs for mountain bikes and, more recently, road bikes.
The number of gears has increased over time. There has been a change from “friction” to “indexed” shifting, but many of these technicalities are too detailed to explain in this column.
And now gear-shifting systems have gone electronic. Switches, connected by wire, or connected wirelessly to a battery pack and a small electric motor, are threatening to replace control levers completely. Or are they?
With the electronic system, the rider only requires a light touch to two switches. Shimano introduced the new system at this year’s Tour of California. The system has given rise to an ancient controversy: the endless debate about whether technology is destroying the spirit of sport. It is, of course, a valid debate. The point of cycling is the direct interaction between the rider and machine: his or her effort and the bike’s ability to convert that effort into forward motion.
Now, between man and machine comes … well, another type of machine.
The Dura-Ace Di2 7970 was used by three professional teams competing in California. Electronic systems have been tried before, and have their drawbacks. Shimano claims it has overcome the problem of rain affecting the electronic system, but there are still concerns over the lack of a manual override if the battery fails. Shimano estimates the battery will last for about 1,600km per charge.
It is thought in some quarters that the electronic system will only be of benefit in time trials, races against the stopwatch and triathlons. Certainly, an earlier version of the electronic system, used by Chris Boardman in the opening time trial of the 1997 Tour de France, was credited with the two-second margin of his victory, as Boardman was unaffected aerodynamically while shifting gears.
For racing bikes, it might be a different story, as riders, who vary their pace and break into sprints, like to be in control, and there is nothing yet as responsive as the human brain. No doubt science will rise to the challenge, and the human brain will surpass itself. Can it be outsmarted by its own invention?
If the answer is yes, the world will again change forever, and sport itself will be re-defined; it won’t just be about the bike. Another controversy for another time …
That enough gears for you? (Photo: Getty Images)