When Zap asked me for some recollections of Mavic in the early US days, I took the moment to contact an old friend in San Francisco who had a lot Mavic experience, Richard Goodwin. We each put pen to paper and wrote a few words about the past, nothing serious. Folks from that era who aren’t mentioned are not forgotten. These are just brief reminiscences.
Now I’ve decided to share them with you. Time passes, but the memories live on. Read more →
Wood is a spectacular building material, delivering great stiffness and low density. The contemporary product environment is more material aware than ever. We enjoy a vast range of mold able plastics, metals, and composites and today’s designers are also aware of the great potential of wood. Careful selection of species and grain, combined with modern adhesives and fabrics for reinforcement helps wood reach new potentials.
Early sporting goods depended heavily on wood (bats, ski’s, backpacks, etc.), as did boats, airplanes, furniture, and musical instruments. Today, amazing feats are being accomplished with advanced design and wood. High on my list are lightweight boats, like those made by Joe Greenley at Redfish Kayak in Port Townsend, WA. His wood wonders are among the fastest and lightest boats available of any material.
As you can with Wheel Fanatyk, I’m quite fond of wood rims. It’s more than nostalgia, the material makes a wonderful rim regardless of the vintage of bicycle you have in mind. I’m surprised wood rims are so little appreciated, given their virtues. However, many bicycle frame builders have discovered wood. Here are a few:
Bamboo frames by Craig Calfee have received lots of publicity, including the LA Times, Sundance Institute, and Outside Magazine.
hemp and bamboo seat cluster
To understand how a wood rim functions, we need to talk about density and the stiffness of shapes and materials. A bicycle rim resists bending according to the stiffness of the given material and shape. However, material near the rim’s exterior does most of the work. Why? When the rim bends, this exterior undergoes the greatest deformation. For example, with a bend to the left, compression is felt on the left and tension on the right. These forces are greatest on the surface, furthest from the rim centerline. As it bends, the magnitudes of compression and stretching are greatest on the surface and this area puts up the greatest resistance. If the rim were solid, material in the center would barely detect the bending. For every degree of bend, internal deformation is smaller than that on the surface.
This principle favors tubes, whose mass is concentrated in their perimeter, far from the centerline. Therefore, hollow shapes are efficient and we certainly get our money’s worth from the metals. Composites, likewise, end up imitating metals to produce efficient structures. How does a wood rim resist bending forces? After all, it’s a solid that, according to the previous evidence, makes an arguably inefficient structure. Wood is much lighter than metals or composites, and this low density is what it leverages as a wheel rim.
Density (g/cm3)
This is a huge difference, so wood is going to make a very different rim.
A deep riding position reached its extreme in the early ‘80’s with new aerodynamic ideas. Even leisure riders had little option than to follow the trend to uncomfortable but efficient postures. Recently, more attention has been paid to the needs of some overlooked niches (women, older riders, etc.) and alternatives entered the market. As the industry ran out of customers who swallow fashion unquestioningly, it’s been noticed that women outnumber men and mature riders are buying more bikes than youth.
An overreaction is typical of herd behavior and many very upright positions have become available on high performance bikes. From the competition point of view, this trend seems to have gone too far. Competitors are not changing the way the market does.
So, it’s a good time to review the costs and benefits of back angle:
