Originally Posted by hobbsc
Where did the mountain bike wheel sizes come from? Is there something magic about the numbers 26 and 29? Why not 25 or 30 inch wheels?
Standardization is the reason for the wheel sizes. Early bikes had wheel diameters all over the place. Ordinaries (big wheel bikes) had different sizes depending on the rider because the bike wasn't geared. The 26" mountain bike wheel came from the Schwinn Excelsiors that the guys in California were using. When they started building their own frames, they just kept the size because they could get wheels and tires easily.
The 29" wheel is really a dressed up 700C road wheel. Europe calls them 28" wheels. The size depends on the outer diameter of a idealized tire. The inner diameter of the rims are 622mm which is a 24.4" diameter. Confused yet?
Originally Posted by hobbsc
Rear suspensions, who first came up with the idea? Is it a "new" thing?
The rear suspension is way old.
Here's an early but not the earliest from 1892.
Here's an early front suspension.