Diamond bike frame

slingshot

Sorry if the title’s a bit of a clickbait – you won’t find an actual diamond covered bike here – but what you will find is the classic ‘diamond’ shaped bike frame plus some wonderful variations on the bike frame theme.

The modern bicyclebicycle_frame_diagram

We will leave the story of the origin of the modern bicycle for another day. Most people will recognise a Penny Farthing (known as the ordinary bicycle) which is not the safest option on two wheels: think high centre of gravity combined with stopping quickly and cycling up or down steep hills. So the need for a safer solution was clear. Through many iterations, we eventually settled on bike frames comprising a double triangle, hence the name diamond shaped bike frame.

Extreme variations

Modern technology, competitiveness and human yearning for pushing the boundaries has given us some very unconventional takes on the bicycle theme. The most famous ones must be the Lotus bikes and the Old Faithful.

Chris Boardman rode the Lotus 108 to victory on the track at the 1992 Summer Olympics 4 km Pursuit. He also broke the then hour record on board the Lotus 110. On the other hand, Graeme Obree built the Old Faithful from BMX tubes and bearings from a washing machine and went on to break the hour record on it twice.

Denise Mueller recently set a new women’s bicycle land speed record on board a specially designed bike. It still has the diamond shape but does look like a cousin of a chopper motorcycle. A closer look will reveal a range of suspensions, stabilisers and the double chainrings to give her a gigantic gear ratio on a fixed gear bike.

slingshotLess famously (some might say infamously) the Slingshot has no downtube, one side of the diamond shaped frame being replaced by a taut wire known as SlingPower technology (see pic). A quick search on the interweb reveals they are still selling bikes with this technology (though not massively popular so it must be an acquired taste).

Moderate variations

The triangle is a strong geometric shape which is why it features on bikes wherever possible. And you’ll find them in a lot of civil engineered structures too, as well as the humble corrugated cardboard. However, some commonly used bikes do away with the double triangle, diamond shaped frame.

The most obvious is perhaps the step through bike but fold up bikes and tandems have also done away with the diamond shaped frame for good functional reasons. Less commonly seen are recumbents and adapted cycles. Some of these may be heavier to make sure they are strong enough but none of them involves cycling 6 feet off the ground like a Penny Farthing, phew.

Consolation

To make up for the lack of diamond covered bikes in this world, there is a gold plated bike which was made by Ernesto Colnago for Pope John Paul II in 1979. Not many people would return a gold plated bike but that’s exactly what the Pope did after a year, stating that he wanted a bike with flat handlebars. Which Colnago duly delivered.

 

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