One of the objectives of this trip was to test out these wooden bicycle frames. It hasn’t worked out exactly as we planned. We anticipated logging about 1,500 miles. Instead, I think we rode about 250 miles on a couple of them. A crash is about the most stressful thing that a bike frame can endure. After Ella’s crash, we handed her bike down to Anna, so Ben could take over Anna’s bike. Anna then crashed the bike a second time. We have nicknamed that bike the wrecking bike, and it is still fine. If it were a carbon fiber bike, we would have thrown it away after the first crash. The wood, on the other hand, took the impact. The bikes weight about 22 pounds (10 kilograms). The wheels on the bikes are made by Velocity, and they are fantastic. They are the bomb diggety! Europe has many cobblestone roads which are really, really rough. The loads, the torques, and the bumps have not phased the wheels. We are using Continental tires. This is my third tour using Continental tires–8,000 miles and only 3 flat tires! One of the three flats was my fault because I had to fold the inner tube and the friction on the tube wore a little hole in it. They have been holding up great, though.
The engineer’s dirty little secret is a safety factor. We test something until it fails and then advertise that it will fail at a lower value. When I worked at Ohio Willow Wood designing prosthetic components, for example, that factor was 2 to 2 1/2. That is why the roof rack on my van says it is rated for 100 pounds, but I’m pretty comfortable putting 150 pounds of bikes and boats on it. Shhhh don’t tell anybody. I tested our wooden frames on an Instron test machine before we left. I tested one frame until it failed at 430 pounds, and it wasn’t exactly a catastrophic failure. The bike still could have been ridden–just a broken seat stay. Benjamin, the load on the tandem, and I combined had a safety factor of 2. When I put Ella on board (she weighs twice what Benjamin weighs), the safety factor dropped down to about 1 1/2. Shhh don’t tell Andrea. The real test of the tandem was the day Anna crashed. We weren’t able to get the tandem on the trailer to haul to Cochem, so Sarah and I had to ride it fully loaded. With adrenaline, we were going about 20 to 25 miles per hour for about 15 kilometers, all the way to Cochem. We really stressed the bike out, a good test.
Anecdotally, the wooden bike frames seem to be a real hit in Germany. Folks double take whenever they see them. When we park, crowds usually gather around. They knock on the frame and ask, “Holz fahrad?” (“Wooden bicycle?”). Yea, that’s holz. We are always amazed when people flag us down to ask about them. I think the bikes have been a success. I wish we had more miles on them, but they have had their share of torture tests in ways that I didn’t anticipate. I’m looking forward to further developments.