It's been a while since I've had a hand in a 650b conversion. Yesterday, we finished converting Beth's old Schwinn Voyager to 650b. It was a group effort: Glen did the brazing. Mike did the managing. Stine did the build out. I wrapped the super important twine on the grips. It takes a village.
As we were pulling this mini-project together, I thought about how common place this conversion has become -- maybe not in the conventional big box bike world, but for sure in the smaller nerdery bike world. I think the first conversion for me was in 2006. The Trek. Liza's RB-1. Then Liza's Fuji. Then my RB-1. There are probably others.
Buddy Rory, part of the Wetmorian Seattle Crew, wrote about the 650b conversion in a Rivendell Reader (#33) many years ago. He's the guy that I credit with figuring this out. It's a great solution for all those great steel road frames from the 80's and 90's that only take skinny tires. If you can braze on some canti posts, it's even more awesomer as a solid, practical, long-term bike solution.
The main thing that I've learned about this conversion is not to over think it. Specifically, don't get all hung up on trail numbers or bottom bracket height -- compared to the skinny-tire racey thing, the converted bike will be better for 99% of the riding normal people want to do on a bike (ride on crappy streets, hit a trail here and there, load it up with racks and crap from the store, ride a friend on the top tube, etc).
The 650b conversion for me is about the hack. I know for many in the bike nerdery world, it's about cultivating the fetish, but I see this conversion as an eminently practical solution. And once you take what was a pretty cool racey frame, cut stuff off it, and braze other stuff to it: you've freed the frame and your fetishy weirdness into a liberated space of experimentation and hackery.
Part of our internet thing is to sit in isolation and look at bikes and components and parts and other people's experiences and project ourselves into those situations. Bikes, and the experiences that they might afford, become part of a consumerist ideal: if I can just get the right stuff then I'll have that rad life. God knows I've been there. This mindset is often manifested in the fetish bike mindset. And its antidote is the hack. Any hack. Preferably with friends. And a few drinks.