Great to have such a wide variety of non 26" wheeled bikes.
The history of mountain-bikes has been influenced by the economics involved in creating new tyre sizes.
In the case of larger diameter mountain-bike tyres: Why invest in the manufacture a larger tyres, when they will not fit existing bicycles?
The commercial dominance of the 26" size between 1982 and 2000+ was more a matter of what was commercially expedient for manufacturers than what was optimal from the rider's point of view. However, on the fringes of the MTB world there was much more interest in alternative wheel sizes.
A brief History of US mountain-bike wheel sizes:
In the US mountain-biking starts with John Finlay-Scott built one 26" bike and several French 650b based roughstuff bikes in the 50s and 60s.
The Marin and Larkspur rider's used 26" Uniroyal knobby tyres on their Klunkers in the 1970s.
In the 80's Fisher Kelly and Ritchey chose this size for their bikes because the tyres were readily available and less expensive than larger sizes because they were taxed as children's size. They had access to knobbly Finnish Hakkapeliitta 650b and 700c tyres from 1980 but import costs from the UK and US taxes made them much more expensive. These winter snow tyres were not produced all year round, so supplies were unreliable.
Gary Fisher on the history of MTB wheel size
US frame-builder Bruce Gordon solved this problem in 1988 when he had copies of the 47mm wide Finnish tyres manufactured. Other US frame-builders chose these Rock'n'Road tyres in preference to 26", and in the 1990's one of them, Wes Williams, persuaded Gary Fisher to fund the manufacture of a 52mm tyre. A size that rounds up to an overall diameter of 29".
Gary Fisher was influential enough on to encourage the development of the early 29er bikes and components from the late nineties onward. In 2007, Kirk Pacenti reintroduced the 650b (27.5") size, because he thought that the 26" wheels were too small and the 29er wheels too big. He was unaware that Ritchey and other US frame-builders had made 670b mountain bikes in the early 80's.
The history of UK off-road bicycle tyres was very different, but apart from promoting the 700c size, the Brit's did not have any long-term international influence.
