David Biggs - about getting unchained
ARE we about to see the end of the road for the drive chain that converts pedal power to forward speed on billions of bicycles worldwide? A recently unveiled Danish invention suggest we might be entering the age of the chainless bike. A Danish company that has been producing ultra-low-friction ceramic bearings for roller skates has produced a prototype shaft-driven bike they claim increases the efficiency of pedal power by a whopping 48%.
Chains have been used to drive vehicles since the mid-1980s. The earliest cars were chain-driven. Today most motorcycles are still chain-driven. There does, however, seem to be an ongoing effort to find a more efficient drive system.
Car manufacturers abandoned the chain drive a century ago, and more recently replaced the cam chain with a cam belt, which is an amazing device made from synthetic rubber that only needs replacing about every 80 000km. The main problem with a chain drive is its number of moving parts. Every link creates friction and is subject to wear and corrosion.
The inventors of the new shaft drive say there are only two points of friction. At present the system is undergoing trials, and pretty tough ones at that.
Professional cyclists are powerful people with powerful leg muscles. Can the Danes make ceramic bearings strong enough to survive the Tour de France? They believe they can. If they do, it will certainly revolutionise competitive cycling. As it is, we cyclists go to amazing lengths to gain even a 1% advantage, like shaving their legs to reduce air drag and wearing aerodynamic helmets.
Imagine the upheaval if somebody arrives at the start line with an almost 50% advantage built into his bike! I believe bicycle chains and derailleur gears will still be around for many years, no matter how soon the new bike hits the market. I have several cycling friends and none of them is likely to discard that beloved chain-powered bike for a piece of speedy ceramic and plastic.
The motorcycle world still favours the drive chain in spite of BMW’s shaft drive and the Harley-Davidson belt drive system. It will, however, be interesting to see whether competitive cycling rules will have to be modified to accommodate the ceramic drive. Or will derailleur gears simply slip into history like that old Sturmey-Archer three-speed that carried me so many miles on my old Hercules bike as a teenager? If you remember the Sturmey-Archer gear, you’re probably no longer riding competitively.
Last laugh
A woman’s cellphone ran out of airtime but she needed to make a call, so she found a payphone and stood waiting for the user to finish his call. After a while she noticed he wasn’t actually talking. He just stood there with the phone held to his ear.
This continued for several minutes until she became impatient and tapped him on the shoulder and said: “Are you going to be long?” He turned round, covered the mouthpiece with his hand and said, “Shh. I’m talking to my wife.” Tel: 021 782 3180 / Fax: 021 788 9560 E-mail: dbiggs@glolink.co.za