Single-Fork Frame From The Nineteenth Century - The Invincible Bicycle

May I introduce you to a truly remarkable bicycle?

The is an Invincible, built - amazingly - in 1889. What is so amazing? Look at the frame. What do you notice about the forks?

Yes, there's only one on each wheel.

I wonder whether this bicycle (in the Coventry Transport Museum) is the only nineteenth-century bicycle of its kind in existence.

The frame crosses from the starboard side of the front wheel to the port side of the rear.

You will notice also the mounting step and the chunky chain - unusually on the side of the rider's left foot. The seat tube and saddle fitting demonstrate some pretty muscular piping too.

And, of course, in common with the best bicycles of its decade, it had a spoon front brake.

I have also found out that the French Labor Company produced a single-fork frame in those early days. The selling point was that it was very easy to remove the tyres without having to remove a wheel.

As far as I know, single-fork frames did not appear again until the 1990s, when Chris Boardman won an Olympic gold medal on a single-fork monocoque bicycle designed by Mike Burrows.

Since then, there have been a few other designers using this concept.


My old school chum Michael has pointed out that Cannondale manufactures bikes whose wheels are attached to the frame on one side only. For obvious reasons, they are known as lefties.


Having checked out Cannondale's website, I discovered the latest wonder: the Cannondale Onbike Limited Edition. It seems to be a remarkable piece of engineering.

The front fork is on the port side. At the rear it has, on the starboard side, a chaincase which is a structural part of the frame. This chaincase acts as the chainstay (with no seatstay). This is said to be extremely stiff and light, and it gives full enclosed protection to the chain, so maintenance is minimal.

As you can imagine, such a transmission system works best with a hub gear rather than a derailleur; and a nine-speed SRAM hub is what it uses. The cables are internally-routed in the frame; and disc brakes are fitted.

Shall we soon see the day when all bicycles have frames like this, or will such frames remain a minority option? This bicycle looks like being very expensive but in time I suppose the price of such frames will come down.