"I am familiar with forty-two different impressions left by tyres. This, as you perceive, is a Dunlop, with a patch upon the outer cover. Heidegger's tyres were Palmer's, leaving longitudinal stripes." - Holmes in PRIO

In 1865, the Velocipede was created. The hard materials and steel wheels gave it its nickname the "Bone Shaker." It was an improvement on the earliest bike model, the Walking Machine of 1817. The velocipede was the first to have pedals. The earliest bikes were made of wood but soon manufactures began to use metals. A few years later, in 1871, the "High Wheel," "Penny-Farthling", or "ordinary" bicycle, an all metal bicycle, appeared. One rotation of the pedals would send the bike further with a larger front wheel (hence the monstrous front wheels).

In 1885, in England, the "Safety Bicycle" appeared with similar sized-wheels and incorporating many of the major features of modern bikes. Initially, these bikes were equipped with solid, hard rubber tires; and they were much more uncomfortable than the High Wheels; but, because of their design, they were easier to use and were safer. The designs competed against each other; but from the outset, the safety bicycles were very popular and allowed a much larger number of people to take up cycling. Bicycles, however, were not cheap; and use of them was restricted to those that could afford them.

Bicycles are mentioned in four of Watson's accounts occurring approximately between 1888 and 1901 with VALL, SOLI, MISS, and PRIO. Very few clues are given regarding the bicycles' identities; but forge ahead, we shall.

It is likely, given their popularity, that all the models of bikes found in the Canon were "safety bikes" (instead of High Wheels). But because VALL occurs so soon after the introduction of safety bicycles, this particular model may have still incorporated a slightly larger front tire into the design (some early Safety Bicycles still had slightly larger front wheels). Because pneumatic tires were invented the same year of the story, it is very unlikely that Hargrave's bike was equipped with them. Rather, the bike would have had iron or, more likely, solid rubber wheels, making the ride very bumpy.

Bicycles make another, very important, appearance in SOLI, an 1895 case. Holmes investigates a male stranger following Miss Violet Smith, and both the stranger and Miss Smith ride bicycles during the incidents. During the "gay nineties," a boom in bicycles (due to mass production) helped stimulate women's usage of the machines. Throughout the 1890's, the numbers of women riding bikes rose staggeringly. Around 1894, Betty Bloomers were popularized, allowing women to ride bicycles (as opposed to the adult sized tricycles they previously had been riding) while keeping their legs covered with long skirts.

In MISS, Holmes rents a bicycle when in hot pursuit of Dr. Armstrong. Notably, we find that Holmes at some point took it upon himself to learn how to ride before this account - otherwise, he would have hardly been able to maneuver it so deftly when called upon at a moment's notice. Although he hardly had need of one in Baker Street - nor is one ever mentioned, one can hypothesize that he most likely learned the skill while on vacation in the country. He would have had ample time to master the new skill and a need for recreation and self-transportation.

The last case is which bicycles make an appearance is PRIO. Watson notes a grisly find in PRIO when he says, "we dragged a bicycle, Palmer-tyred, one pedal bent, and the whole front of it horribly smeared and slobbered with blood." The Palmer-tired bicycle was one of two, the other being a "patched Dunlop."

In 1888, inflated rubber tires were conceived by an Irish veterinarian named John Boyd Dunlop trying to give his sickly son a more comfortable ride. Dunlop used rubber hose to pad his son's tricycle wheels and later patented the pneumatic tires, hence the Dunlop tires in PRIO. Dunlop Tires Co. is still in business selling tires. Their website can be found here.

Dunlop Tyres: First in 1888, Foremost Ever Since

Information for this article was taken from A Quick History of Bicycles, Owls Head Transportation Museum, and Bicycle History.