Going grocery shopping right before a snow storm is ridiculous, but as I had no choice today I headed out on the porteur bike to avoid the parking lot mess. 

Thirty pounds of food on the front rack seems to work just fine. For more stuff, I might need to make the rack a bit wider next time though.

Main triangle brazed

I snuck in a few hours this morning to braze the front triangle of Brian's bike. This photo shows what the joints look like while the bike is cooling. The flux, which starts off as a white paste turns to a clear fluid during brazing. This molten liquid both preps the base metal by eliminating surface oxides and helps the silver to flow through the joint...pretty cool stuff. While it cools, it solidifies into this glassy coating. The base metal underneath also cools contracts causing the flux to crack like a broken windshield like you see in this picture.

Porteur Bike

The porteur bike is complete! This design of this bike is inspired by porteur bikes used in the early 1900s in Europe by city bike couriers. Unlike modern bike messengers, which typically use shoulder packs for baggage, early messengers carried loads on large front racks. These racks were heavily braced and carried huge loads of newspapers, grocieries, etc. Similar to today, bike messengers would stage competitive events through the streets, picking up and dropping off huge piles of newpapers along the way:

The beauty of these bikes is that, with front-mounted rack, they are super-easy to load up and maneuver. Unlike the rear mounted racks that became popular in the U.S., these bikes put the load over the front wheel were it can be "steered" during the ride to help keep the bike upright. In addition, you can place the load on the bike while you are straddling the frame so getting loaded is really quick. To make this work, the steering geometry needs to be properly designed. The steering on these bikes is extremely quick to help reposition the bike under load.

I think people are starting to realize that bikes are not just for fun and fitness, they are also a very practical means of getting around. This could mean riding to work, to the store or on errands. Since most trips are only a mile or two, why get in the car? Unfortunately, one reason is that people don't ride real WORKING bikes. A full-suspension mountain bike will not help you pick up groceries!  A functional working bike has a strong frame, fenders, chain-guards, lights and a strong rack. In the early 1900s, when cars were not cheap to own and operate, people rode bikes with these things because they made sense. For many years, bike builders (called constructeurs) like Rene Herse and Alex Singer hand crafted high quality bikes for real people. Sometimes these bikes were super-classy and sometimes they were just basic but they all were well-made and functional. 

I've posted more pix of the porteur bike on my Flickr site. 

Brian's Bike

I got a nice start on Brian's road bike today. This is going to be a stable race bike with a bit longer (than typical) wheelbase, a bit lower and stable steering. I'm using a double-oversized tubeset here with thin walls. Its amazing what the suppliers are doing with some of the newer high-strength steels...

I've had a few people express an interest in learning a bit more about the process of transforming a pile of tubes into a bike so on this build I plan to post some pix mid-sequence. You can follow along on Flickr under the "Brian's Bike" set.

I spent a bit of time working on the lugset this morning. This lugset has decent lines and certainly could be used "as-is", but I thought it would be nice to sharpen things up a bit. I made the biggest changes to the seat lug. Since this bike won't have mitered seat stays, I chopped off the back and gave it lines to mirror the front. Sometimes, I cut details into the lugs using a really small jewelers saw. This allows me to make really tight corners and super small features. For this type of pattern, though, a large half-round file works best. By using even, light file strokes the curves seem to come out smoother than my sketches. Perhaps no one will ever notice the difference with the new lines, but I don't care...to me its the little things that give each bike their own personality.

The past few bikes have been built with a completely new workflow. I think this bike is already showing the benefits. On earlier bikes, I would build small subassemblies on the fixture slowly integrating part after part. At each step, I would check the parts on the surface plate to make sure that everything was going well. This worked ok, but by putting these pieces together I missed the opportunity to balance the fit of all of the parts at one time. Building a lugged bike is sometimes a negotiation. Since each lug is designed to fit a nominal angle, I'm always working on figuring out the how to best fit things together. This can mean filing, grinding and even a bit of "blacksmithing" to make the fit just-so. Silver brazing works through capillary action...if the gaps are too tight or too loose the silver just won't flow.

In my new process, I've placed my fixture right on the surface plate. In this orientation I can check the alignment of the tubes so that things line up perfectly. Since I spend a bit more time fitting up the whole front triangle, I also get to play with the fit of the lugs even more. When everything is perfect the bike is pinned and quickly tacked together and then brazed outside fixture.

to be continued...