Saturday, February 21, 2009

First Frame - Finally!

Here it is folks... the first bicycle frame I've built from scratch! It's been a long journey, but it's been one of great learning and exploration, and in the end I have a bike I'm proud of and will get a lot of joy out of riding. That's it to the left there, a complete, whole bicycle, save for some accessories I'm still in the process of adding (fenders, racks, lights, etc.).

The story begins, oh, back when I was in my teens, in the 1970s. Back then, I lived in suburban Maryland, not far from Proteus Design, a bike shop that also housed a framebuilding operation. I used to go over there and drool over the hand built frames, and the gorgeous components they'd hang on them, and dream of one day owning one. (Parenthetically, I finally did get one, about a year ago... more on that another day) Then I learned that they offered a class in framebuilding, in which you'd build your own custom frame under their guidance. It was just a dream then, one I couldn't afford, but I finally managed to take a course from United Bicycle Institute, in Ashland, OR, in Novemeber of 2005.

The class was amazing... Ron Sutphin, who runs the school and teaches many of the framebuilding classes, is an excellent teacher, and the other folks he had in to help teach were also very good. And the class was a fun bunch of people... there were 8 students total, and I was the old guy in the group, in my 40s... most of my classmates appeared to be in their 20s or maybe early 30s. A pretty varied set of backgrounds and interests... some others from bike shops, others not. And the bikes we all chose to build varied quite a bit as well. My choice was to build a touring bike capable of handling some mild off-pavement journeys loaded with camping gear.

As a starting point, I took the dimensions of my 1986 Miyata 1000 touring frame, and then made a few modifications. The two primary changes I made were designing in clearance for larger tires (700x42mm with fenders), and using larger diameter tubing with thinner walls. The first was to make the bike better suited to the off-road riding, and the tubing choice was largely an experiment, to see if I could make a lighter frame that would be as stiff as the Miyata.

One of the first things we did in class was take measurements of each other (it's hard to measure yourself) and begin a full size drawing of our frame. Throughout the rest of the two week process, we kept going back to that drawing, in many cases working right on the drawing to lay out and mark the pieces for cutting, as shown here to the right. The overall structure of the class was for the instructor to demonstrate a step in the process, after which we were given a chunk of time to do it ourselves with our projects. I have to say, they really have it down to an art with the organization of the class... while at any given moment each of us might be at a slightly different point in the process, nobody ever got totally behind or ahead of themselves, and we all learned a lot, and had fun doing it.

At the end of the two weeks, we each had all the basic brazing and assembly of our frames finished. We learned the procedures for checking alignment on a surface plate, as well as using more basic tools, and the final frame "prep" was also covered - facing and reaming the head tube so both faces are parallel and the correct inside diameter; facing and chasing the threads for the bottom bracket; and reaming out the seat tube to accept a seat post. What remained for us to do once we returned home was "clean up" work... basically filing any imperfections and smoothing out some of the joints in the frame (particularly where the dropouts meet the stays or fork blades, which you will understand better if you look at my Flickr album). After that, we could take it to a painter or powder coater and then build it up into a bike.

And therein I hit my snags. Long story, not worth going into, but after a good start on this part of the process, I hit a pretty major motivational slump, and aside from a few sporadic stabs at making more progress, the project lay idle for a long, long time. So I had a partly filed frame gathering dust, and as time went on, that in itself made getting up the gumption to move forward difficult.

This past autumn, however, as I've noted, things improved, and I began to get some neglected projects completed (see my flurry of Bridgestones in October/November). And this helped me to get the energy to put the frame back into the workstand and pull out my files... and after a couple of weeks of working around my work schedule, and I was ready to take it to be powdercoated. Thanks to a combination of Crag's List and a friend of mine, I found a shop that does a lot of bicycle work, and seemed to "get" what a bicycle frame requires, so I took it to them. Two weeks later, I had the frame back in my hands, and began building it up into a bike. And there at the top of this post, you see it, in all it's glory. As of today, it also has a rear rack (a Tubus Cargo in black) and a green Carradice Nelson Longflap saddlebag. Soon to come is a set of fenders... silver aluminum ones from a company called Velo Orange, in Annapolis, MD... a style they call the "Zeppelin", because the cross-section is faceted, much like the cross section of an old dirigible. I think they'll look really sharp.

I've posted some photos of the process and the bike, from start to today, on my Flickr account:

And watch this space for future developments. If all goes well, this will only be the first of many.

Thursday, February 12, 2009

Shaft Drive bikes

Well, Monday I encountered my first shaft drive bicycle. If you haven't at least heard of such a thing, I'd be surprised. Along with "automatic shifting" bikes that crop up every few years, the "chainless" bicycle in one form or another periodically gets trotted out as the biggest "new thing" to hit the bicycling world ever.

Okay, so that makes me sound like a luddite, or in the bicycle world a "retrogrouch", I suppose. But the fact is that both of the above ideas have been tried many times in the past, with varying degrees of success, yet the chain drive bicycle with gears operated by the rider still remains dominant. I've got some ideas why, and we'll get to those shortly. First though, some pictures:

To the left here is the business end of the bike... showing the drive train. Notice the total absence of a chain. The first thing that struck me (after "what's wrong with this picture") was how tidy it all looks. Let's face it, chains tend to be dirty, and a chain type drive train, especially on a derailleur system, looks kind of cluttered compared to this. And that in a nutshell is one of the primary selling features of shaft drive bikes... it's tidy. Read the ads, and that's what they focus on... how it does away with all the messy aspects of a chain drive. And I can't argue with that... it is a tidier setup.

To the right you can see a closer view of the front end of the system. Where you would customarily have a chain ring or multiple chain rings attached to the crank, here you have an enclosed gear box, containing what I believe is a set of bevel gears... two cogs at 90 degrees to each other, with the meshing, toothed faces angled to 45 degrees, so they convert the rotary motion of the pedals and cranks in one plane into the rotation of the drive shaft in another plane. And you can see, there is no chain or toothed chain ring to make a mess of your pants leg.

And here is the rear of the system. Obviously that is the back end of the drive shaft, and inside that housing by the axle is another set of bevel gears that convert the rotation of the shaft back into rotation in line with the wheel and cranks. It's hard to see in this picture, but the whole system basically connects to a Shimano Nexus 7 speed internally geared hub, a fairly standard bit of bicycle hardware, and very reliable and pretty efficient. And again, no messy chain or exposed sprockets back here either.

So if it's so clean and tidy, what's not to like about it? Well, first off, it's kind of heavy... heavier than a single chainring, sprocket, and chain would be, driving the exact same Shimano hub. How much heavier? Well, I don't know exactly, not having the specs, but it's probably not a huge weight penalty, and honestly, I don't stress that much over a little weight on a bike, especially if it's not a competition style bike.

A much bigger issue for me is the proprietary, or "single source" nature of some of the vital parts. I give this manufacturer bonus points for incorporating the Shimano hub, instead of using something of their own proprietary design, but the drive shafte and gear boxes and cranks ARE proprietary. Why is that a problem? Well, an awful lot of companies that come up with "innovations" in the bicycle industry don't survive, and if this company were to go out of business, you'd be hard pressed to find replacement parts. For that matter, even with the company in business, you're not going to be able to walk into your local bike shop and expect them to have the parts on hand. I'm sure the manufacturer does have provision for shops to order parts, but that's not always as easy or quick as getting more standardized parts, such as chains, cassettes, and chain rings, which are all pretty well standardized in the industry. (Okay, so there are in some cases multiple "standards", but availability of spare parts is rarely a problem.)

And finally, one thing you don't see the manufacturer touting as a virtue of this system is its efficiency. There's a good reason for this... it's not that efficient. Way back when I was in graduate school for technical theatre production, we had a couple of classes in physics and machinery for the stage, and one of the things I learned there was that for efficiency and reliability, it's hard to beat plain ol' roller chain and sprockets, of which a bicycle drive train is a prime example. In terms of energy lost in the process of transmitting power from point A to point B, few other transmissions are as efficient.

So while there are certainly some benefits to the system, all in all, I'd rather have a chain drive bike, with perhaps a good chain guard or fully enclosed "chain case" to keep me clean. That way I can walk into any bike shop and get replacement parts or have it serviced without any concerns about the shop never having worked on one before. And I'll have a lighter, more efficient bike to boot.

The maker of this particular bike is a company called Dynamic Bicycles. Look for them on the web at: