Image courtesy Renovo
One of the best cases I've seen for the use of wood in structural applications is put forth by Renovo Hardwood Bicycles of Portland, Oregon.
Wanting to separate away the wrong, yet common perception that perhaps cheap quality consumer woods might be used on their frames, they say :
"Consumer wood products are not engineered for light weight and high performance, nor are they joined, fastened or finished to endure challenging outdoor conditions and high loads, so knowledge of wood based on commonplace wood products is no more relevant to a Renovo frame than it is to other high-tech, all-wood structures like: a 350' laminated wood bridge in Norway, the magnificent 154' wood yacht Scheherazade, and the Falco all-wood 200 mph airplanes. These modern engineered applications of wood are designed to last a lifetime in highly stressed, adverse conditions."
Yes that's right. Some of the most marvelous designs out there incorporate the tried and true strength and toughness of engineered wood such as the following :
I was surprised to learn that the "Timber Terror" Mosquito was built out of laminated plywood! To take that to brutal war must have had the designers pretty convinced about the suitable properties of wood to begin with!
Building an eye-catching yet strong bicycle frame out of Douglas Fir might be now easy task for the family run company, but all that colorful background experience from engineering lighting fixtures to building composite kit airplanes and other wood products might help. Besides, Mr. Wheeler was always a bike nut since college days.
The bike has a relatively non-aggressive and comfortable frame weighing anywhere from 3.5 to 4 pounds. All the wood is bought kiln dried through vendors with the appropriate moisture content and then cut/machined with their aresenal of high tech saws and CNC machines.
The frames are made starting with two halves, bonded along the center line using modern adhesives in a climate controlled room and are then cured in their facility for additional strengthening of the bond.
Metal inserts are placed in the structure at the headtube, seat tube and bottom bracket areas. The bottom bracket shell is bonded to the frame with epoxy and fastened mechanically. According to Renovo's testing, over 2000 pounds of force is required to tear the shell off the frame. So unless you've handed your bicycle to your pet elephant to ride on Sunday morning, you'll be fine!
The exterior of the hardwood monocoque is then given a thorough refinish.
The bike's sizes may be standard, but everything else is custom built, according to the customer's choice of grain, color and type of wood!
For additional FAQ's about hardwood usage in bicycles, you can visit Renovo's website here "Wood, Seriously" or read my somewhat related 3 part series on Bamboo Bicycles :
Bamboo For Bicycles Part 1
Bamboo For Bicycles Part 2
Bamboo For Bicycles Part 3