Positron shifting systems over the years. The Positron was Shimano’s first attempt at indexed shifting. But I have never heard of the Tokheim indexed shifting system. The Tohkeim Corporation, out of Fort Wayne, patented this system in 1972. That predates Positron by a several years. Thanks to Park Tool for unveiling this interesting piece of bicycle technology from yesteryear.I’ve worked on a few
_ I love a beautiful bike as much as the next person, but when it comes to riding in snow and slush, I prefer to ride something that’s a bit more low brow. Not that snow, per se, is particularly hard on bikes. After all, it’s just frozen distilled water. It’s the collective elements put down to keep cars, trucks and buses from sliding around that wreaks havoc on bicycles… more specifically, sand and salt.
If you ride in an area where the streets are sanded and salted, I don’t have to explain just how corrosive this is to a bicycle, especially the transmission. Now an internal geared bike is a great way to go, but building up a 14 gear Rohloff may not be in everyone’s budget. Even old school three speeds, which can be had for a fraction of the price of a Rohloff, are geared so tall that they usually require steroid injections for comfortable use. In fairness, you can replace the rear cog with a 22 or 23 tooth gear. This modification makes an old Sturmey 3 speed work for normal humans. But I hate to see nice old 3 speeds ruined by the nasty old wintery elements.
The other way to go is less costly and can give an overripe bike or frame a second chance at usefulness. I’ve had a few snow bikes over the years. The last couple of years, I’ve ridden an old Raleigh Super Course. It has definitely gone to seed, but I love those Capella lugs, so I thought it deserved a break this winter. Instead, I decided to go with an old Nishiki mountain bike I found at the Iowa City Bike Library. I did a transplant on most of the parts from the Super Course, but I did make a change to the transmission.
This time around I went with a 2 speed friction transmission. My thought was that on snow and ice you’re really just trying to maintain a steady speed, but there are still hills to climb and deep snow to chug through. And I like the fact that with high/low shifting, I basically have an indexed system. Lever goes down for low and up for high. This makes shifting in bulky mittens a breeze. I also have a studded front tire.
We’ve had very little snow in Iowa City this winter, but I did take it out this past week after we got a couple of inches. I’m thinking it works pretty well, however, I won’t be able to make a final judgment until we’ve had our first blizzard. I’ll keep you posted.
_Here’s a 1955 British Railway promotional film that is sure to amuse you. The Cyclists’ Touring Club takes the “Cyclists’ Special” train north from London to Rugby where they unload their bicycles and meander through the hills and dales of the British countryside, all the while throwing back pints of stout and nibbling on biscuits. This film has been floating around for a few years, but if you haven’t seen it, take a 15 minute break and enjoy the tweedy goodness!
_ The end of 2011 was unseasonably warm with daytime temperatures in the mid 50s. I was fortunate enough to be able to get out and ride on Friday and Saturday. I know that winter weather and snow aren’t far off, so I’m putting the finishing touches on my new duo-speed snow bike. More on that later. Meanwhile, here's a couple of warm-weather-in-December pics with a gratuitous shot of some Ironweed bags.