Originally Posted by cyccommute
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?
The rear suspension is way old.
Here's an early but not the earliest from 1892.
Here's an early front suspension.
Excellent analysis. I'd like to offer my opinion on "28ers". Over there, cyclocross is popular and if you measured the tires you'd find they come out to about 28 inches. Though, this must be folks from the UK as I cannot imagine folks on the continent using Imperial units. We get "29er" because we're using truly FAT MTB tires instead of the merely "enhanced" tires like a cyclocross bikes. Just wait till we donwhill MTB tires and have 3.0" tires, then we'll have 30ers ;-)