Bicycles - The most efficient form of transport known to man.

How to apply the formula? The function is to get the rider from A to B. This may be slowly or quickly but either way it's best if the bike is safe, efficient and reasonably comfortable. The burdens of a bicycle are; the cost of buying it, the effort needed to pedal, the space needed to store it and the work and cost of maintaining it. Availability is greater if the bike works in all weathers and can cope with a variety of surfaces:

The bike pictured left has high availability because it has mudgaurds and a mud-flap for use in wet weather, dynamo lights for use in fog and the dark, and tyres with enough grip to allow use on a variety of road surfaces. It's replacement cost isn't high enough to prevent it from being left outside (locked up) all day.

Burden is quite low as it has a fairly low purchase cost. It only has one gear which means low maintenance. The dynamo lights mean there's no fiddling around with batteries and whilst the tyres have some grip they're not too fat and knobbly which means peddling doesn't take too much effort.

Function though, is fairly limited. It's single gear means it's not good on hills and it also limits the top speed, as legs can only go round so fast. The flat handlebars mean there's only one position for the hands so there's only one riding position.

The bike right is a bit different, on show at the 2005 Tour Of Britain, it could (if ridden by a rider capable of winning races) win races.

It's availability is low as it has no mudgaurds (or space to fit them), no lights and doesn't have room for larger tyres. So, if you use it in the wet it will spray you with water from the road, if you use it in the dark you'll be breaking the law and risking your life, and if you use it on road surfaces other than nice smooth tarmac or asphalt then it will be uncomfortable and susceptible to damage.

Burden is quite high as it has a very high purchase cost and needs regular maintenance. It's narrow 10-speed chain will wear out far more quickly than a single speed chain and it's high performance tyres will need periodic replacement.

Picture from

So, what would be a really usefull bike? Low cost but reliable, with a riding position, tyres and equipment that suit the types of journeys the rider makes.

For some people a good quality old 5 speed racer might be pretty good. But finding replacement parts might be tricky.
A folding bike will use less space but can add weight, hub gears are more reliable but can add cost. An electric bike will need less effort to pedal but can cost more, this page makes a good argument for electric bikes.

Links Giant Defy | Pashley Countryman | Thorn Club Tour | Moulton TSR | Giant Prime E+ | Folding Electric | Bike Friday - Alfine 11 | Dawes Geneva | Ultralite | | |

Usefulness = (Functionality x Availability) – Burden