January 28, 2006
Boutique parts
An interesting thing is happening in the bike biz: manufacturers are beginning to find a market for cool, practical bikes.
It turns out not to be such a difficult thing to do, even at these small volumes. A lot of good parts are already out there, and a lot of the component manufacturers still have the stuff they were making back when bikes made more sense. A lot of the good stuff--dynohubs, internally-geared hubs, touring/mtb cranks, fenders, lights--are available in other markets overseas. So some small companies are starting to build and market practial, stylish, fun bikes and bits for real-world conditions. Look at Rivendell, Kogswell, Surly, Bianchi, ANT, Paul. All of these companies are marketing real-world bikes and parts I'd be more than happy to own and live with. (And I do.)
There's nothing new here. The basic diamond-framed safety bicycle has been around for 120+ years. There have been lots of tweaks over the years, mainly around subtle changes in frame geometry, or improvements to gearing and brakes, and standardization of parts and fittings. Most of the big changes have been around material science--lightweight aluminum alloys and composites for some parts, improved metallurgy in wearing and stressed components, composite materials for frames and other parts. The bicycle goes through major design changes and phases of innovation, and then a lot of the dead ends are tossed over the side (aero components, chainstay-mounted brakes, etc), or lead to improvements where they matter. Some good things are marketed away for a while--friction shifting, epicylic gearing (and multi-speed fixed gears), steel frames, center-pull brakes, utility bikes--but maybe it comes back again. Some of it looks like it's coming back now.
Speaking of epicyclic fixed gears, we've gone almost half a century without a production multispeed fixed hub. (Production of the Sturmey ASC, above, ceased in about 1962.) It may be time for another one, but is there a market?
If people are starting to engineer and machine their own, it's definitely time for a limited production run, because for every wacko with some mechanical design skills and access to a machine shop, there must be another 200 wackos out there who know about it (thanks to the Internets) and want one, but don't have the skills or knowledge or access to build their own. And each of those 200 wackos must know another 20 wackos who'd want one, too. So we're looking at an initial production run of about 4,000 units. That's not a lot, but it's a start, and it's enough to warrant some shop time.
I'm not looking for a soup-to-nuts 2- or 3-speed fixed gear hub. I'll settle for a conversion kit, similar to what some people have already done with their Sturmey AWs and Sachs/SRAM Torpedos. This would be similar in concept to Surly's Fixxer (essentially a one-piece kit to convert any freehub to a fixed-gear hub), but more mechanically complicated.
What this thing should do:
- It should give you at least two fixed ratios: a regular cruising gear at, say, 72 gear-inches, and a drop-down climbing gear at, say, 62 g-i. So we're looking at about a 10-15 percent change in ratios. Think a difference of about 2 or 3 teeth.
- It should be a straight conversion--no additional machining required. That's why a conversion based on the Sachs Torpedo probably makes the most sense.
- A two-speed hub shouldn't require any fancy shifters, because it's basically a push/pull switch. You should be able to make it compatible with any friction shifter. And if you can figure out how to do a 3-speed conversion, make it compatable with the conventional Sachs/Sturmey 3-speed shifters. None of this proprietary funny business. (Basically, you want to make it so that if some lucky soul finds one of these things at a yard sale or a bike swap in 50 years, they can take it home, lace it up, and jury-rig their own multi-speed fixie without trolling for years on eBay for the right shifter.)
- A third, ultra-low, freewheel bailout gear would be icing on the cake.
- Engineer it so that if Superman Torpedo blows up, he still gets you home, and hopefully doesn't take the rest of the hub with him. In other words, if it fails (which it won't, because you did such a great job designing and fabricating the thing) it should fail gracefully, and in such a way that the buyer can say, "Well, that was fun," and then gut the thing and turn it back into a conventional Clark Kent Torpedo, with no hard feelings.
Caution: this kit will probably void your hub's original warrantee. Use at your own risk.
So who would build such a thing?
There are plenty of machine shops out there. (Think of all the Harley-Davidson tuners and tweakers--especially the ones doing performance transmissions.) Basically, once you have your design, you need somebody who can cut gears and mill out a new planet cage, clutch and driver ass'y. (I'm oversimplifying things a bit, but you get the idea.) Somebody with a CNC milling machine and access to a heat-treating facility. If you can search and find good off-the-peg parts (Is somebody already making the right gears or pinions? Is that stuff standardized?), so much the better, because that would reduce fabrication costs.
Posted by smasher at January 28, 2006 03:17 AM | TrackBack