June 16, 2007
I wrote this piece for the February 1985 issue of BICYCLE GUIDE magazine, pg 16-17, 106. So please forgive a few details that are owed to its vintage. Also note, all the wood rim makers listed have ceased production except for Ghisallo.
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In our never-ending search for better materials, the current rage is the space-age group of substances known as composites. Composites consist of microscopic filaments, which are bonded by glue into dense layers sandwiched around lighter materials. Perhaps the best-known composite system is the surfboard, in which styrofoam is covered with a thin layer of fiberglass and polyester resin to create an immensely strong but light structure. Composites using carbon fibers are currently revolutionizing aeronautics, as well as sports equipment such as tennis racquets, skis, golf clubs, and fishing rods. And the wheels that contributed to our Olympic track team's success were also constructed with composite materials.
But as we consider these materials, it helps to remember nature's own composite - wood. Structurally, wood is a system of fibers bonded by resin and arranged in sandwich layers around a light pulp center. Nowhere has this natural composite make such a valuable and enduring contribution to the bicycle as in wood wheel rims. The age of wood rims began at the dawn of cycling and, despite major advances in steel rim design and manufacture, continued until shortly after World War II. Whether for Madison-style track racing or for the destructive cobbles of Paris-Roubaix, wood had an unchallenged 130-year reign as a rim material that combined lightness with strength. Famous names of rim manufacturers such as Fairbanks-Boston (Michigan), Sieber (Milan), Mirass (Spain), and American (Michigan), bring back the scenes of great cycling battles staged on the polished wooden surfaces of dimly lit velodromes. Nothing could match the liveliness of wood rims on these tracks. "The tires just sang on wood rims,” observes former six-day rider Vince Gatto of San Jose. Their popularity faded only with the arrival of high strength aluminum alloys. When the first aluminum rims appeared, they seemed "dead" or "flat" compared to wood, but what they lacked in feel they gained in reliability and safety: they stayed true longer and they didn't shatter upon impact.
Wood's unique ride is partly due to its flexibility. Although aluminum may be stronger, wood can usually bend farther without sustaining a permanent deformation. This is a boon when striking a pothole. Also, small bumps and high frequency road vibrations are better absorbed by wood. A quieter, smoother ride results.
Wood's flexibility is a virtue in a world of poorly paved roads, but a liability in terms of strength. The wheels of today require high tension to accomplish feats like six-speed spacing. But wood rims can't withstand the highest spoke tensions, so they are better suited for track, five-speed, or symmetrical wheels that have less dish. Low spoke tensions can be noisier as the spoke shafts rub against each other, especially at the outer cross. This clicking sound can be silenced by tying and soldering, which helps explain the popularity of this practice in the past.
Wood rims also account for the early popularity of butted spokes. Butted spokes are more elastic than straight gauge spokes; they give more and accommodate the wide tension variations inherent in wooden rims. Butted spokes provide more continuous support at low tension and ought to last longer because they don't snap from full slackness to full tension as often as straight gauge spokes.
Wood makes a great braking surface that provides especially good performance in the rain. Wood's heat insulating abilities places the burden of heat dissipation on the brake pad so it dries quickly in the wet. But the pad is also inclined to melt more readily; with heavy use, the rear brake can spit tiny bits of melted brake pad at the back of the rider's leg. Rapid stops will also cause a very faint burning of the wood's surface, a pleasant perfume for the following rider.
Hardwoods such as hickory, elm, ash, and maple are favorite rim materials that are easily shaped once softened by steam or other moisture. A single piece of wood can be bent into a hoop and connected to itself with an elaborate finger joint, or several laminations can be layered and glued. Waterproof glue is used to bond the laminations while the rim is held round under pressure. Once dry, the hoop is shaped with cutting tools and drilled for spokes. The laminated construction generally produces a stronger and more rigid rim because care is taken to offset the direction of the grain and joint of each successive layer.
To get the most from wood rims it is important to store them in dry conditions; if they become wet, allow them to dry slowly. Each year the rims can be lightly sanded and coated with a waterproofing lacquer.
At least five companies still manufacture wood tubular rims. Three Italian firms - Ghisallo and Berlazzi of Milan, and Sieber, now located in Switzerland - offer rims in many sizes and weights. However these rims require an extra-long, 3/4-inch nipple that is hard to find.
Wolber distributes a French rim made by Darrigade that features full sockets like modern aluminum rims, allowing the use of conventional nipples. This rim weighs just under 400 grams and is bonded with waterproof synthetic adhesives.
Finally, one of Japan's oldest parts distributors, Sanno Sports of Tokyo, can lead you to the Japanese manufacturers that, up until 25 years ago, made wood rims for the Keirin circuit. The rims are hard to find now, so inquire for availability.
Will wood rims stage a comeback? I think not, but their novelty and pleasant ride guarantees that they ought to be available for many years to come. Rims of the future, if not made of metal, will most likely be made of synthetics. But as in the design evolution of other vehicles such as boats and planes, it took a long time to discover materials superior to wood. And it is fitting indeed that the futuristic disc wheels of the Olympics are closer in construction to wood than the tensioned wire and metal hoops to which we have become accustomed.
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