Marin frame-builder Lennard Zinn recalls these early 650b Ritchey/MountainBikes made machines:
"When I was working in Tom Ritchey’s framebuilding shop in 1981, he made some bikes for himself and friends to fit some Nokian Hakkapeliitta 650b tires that Gary Fisher was importing. (At the time, Ritchey was building bikes that Gary Fisher was distributing through his shop in San Anselmo, CA, and they carried the Ritchey logo with “Mountain Bikes,” Fisher’s business name, superimposed over it).The Hakkapeliitta tires were great compared to the 26-inch mountain bike tires you could find at the time. The Hakkapeliitta casing was supple, the weight was low, and the tread pattern was refined, fast, and quite aggressive, whereas the 26-inch tires of the day were just big square blocks on a heavy carcass.
You could even get studded Hakkapeliitta 650b tires, as those were used for bike racing on frozen lakes in Finland, where the tires were made. According to Wikipedia, Nokian adopted the Hakkapeliitta name for its winter tires in 1936. It still uses it.
We used Super Champion 650b tandem rims back then, which were lighter than most 26-inch mountain bike rims of the time.
After all, you should remember that a primary reason 26-inch became the default mountain bike tire size starting in the 1970s and 1980s was simply that import duties on them were cheaper, as the US Customs Dept. charged a higher duty rate on adult bikes than on children’s bikes, and it considered 26-inch to be a children’s-bike tire size.The sweet fillet-brazed Ritchey 650b bikes Tom was making then were great – light, nimble, and faster-rolling than the Ritchey standard-production 26-inch bikes.
When I left Tom’s employ and came back to Boulder, I took a Ritchey 650b bike with me and rode it for years, including in some cyclocross races as well as all over the Crested Butte area on my honeymoon in 1983. I loved that bike. It always drew lots of looks, because there were no others in Colorado at the time.I built a number of 650b mountain bikes after I started my own framebuilding business in 1982, and my customers loved them, but when Fisher could no longer get the tires in 1983 or 1984, I quit doing so".
Taken from VeloNews: What's the big deal with 650b?
By Lennard Zinn
Published Jun. 26, 2012http://velonews.competitor.com/2012/06/ ... 50b_252295
9/16" Suntour BMX MP-1000 pedals / 56 tooth TA 6-bolt chainring.(I'm not bothered if the teeth are worn or damaged)