Tuesday, March 3, 2009

ROAD TEST: The Renovo Wooden bicycle

Back in December, 2007 I noted that:
Portland, Oregon's Revovo hardwood bicycle was described by one tester as "the best ride of my life." With all the hype in the bike industry I took this with a grain of salt. But I'd sure like to ride one of these if and when they appear.

There followed a thoughtful comment from none other than Renovo's Ken Wheeler, who gently objected to the word "hype" appearing in the same sentence as the word "Renovo." Then he offered me a test ride. However, since Portland is nearly 400 miles from Arcata, Ca. the Renovo only appeared in my dreams. Enter Portland's Ken Thiessen, friend, trained engineer and experienced cyclist, who graciously volunteered to merge his body with one of these exquisite creatures.


ROAD TEST: THE RENOVO WOODEN BICYCLE

by Ken Thiessen

FIRST IMPRESSION
In December 2008, I arranged for a shop tour and test ride on a wooden-frame Renovo bicycle. Thanks to Gordon and the Social Biking Blog, mine was not a cold call. I was welcomed at Renovo Bikes by Ken Wheeler, the founder and owner. I was pleasantly surprised by the lack of pretense at this high-end bicycle shop and enjoyed myself from the outset of my visit. The shop is located in close-in southeast Portland among other light manufacturing facilities. The small Renovo sign on the door cannot be seen until you are about to walk in; however, the quality of the entryway woodwork provides a hint of what follows. Once inside, the beauty of the wooden bicycle frames on the wall and the complete bikes on the floor lets the visitor know that the shop produces nothing short of rolling sculptures—and is proud of it.


The Renovo Bicycle combines beauty, innovation and high performance.



Ken Wheeler and one of his creations outside the Renovo shop, Portland Oregon



THE SLOW LANE REVOLUTION

Ken Wheeler appreciates wood and knows its structural capabilities. He works with modern adhesives, and joinery as well as sophisticated shop tools and techniques. His engineering skills coupled with experiences designing and building composite aircraft and boats led to this revolutionary wooden bicycle frame. We spoke about our common monocoque wood-composite boat building experiences as we toured the shop. Soon I realized that had taken structural wood construction to a new level. His previous venture included the design, manufacture and production of Wheeler Express Aircraft. These advanced composite aircraft were noted for their speed, beauty, load carrying capacity and efficiency.

Wheeler seems to have simplified his life and joined the slow lane revolution of bicycle innovation in Portland. With his skills, imagination, expertise and tools, he has created bikes of technological ingenuity, longevity, and exquisite beauty.

Bicycles made of wood first came on the scene around 1800 and were reminiscent of a child’s hobby horse scooter. A more modern wooden bicycle is pictured here: modern primitive. Unlike this modern/primitive bicycle, Ken Wheeler’s fully modern designs do not suffer from increasingly relaxed seat tube angles which sag in direct proportion to the number of miles ridden. Currently, a few other modern all-bamboo cane bicycles are being manufactured; most are often reminiscent of Boy Scout Jamboree lashing projects.



ENGINEERING AND INNOVATION

The efficient double-triangle design of most modern bikes was made possible by high-strength of metal tubing reliable joinery techniques. Wheeler uses wood in place of metal to add different qualities and ride improvements to the double-triangle standard bicycle. The wooden Renovo frames called for substantial innovation and ingenious use of traditional woodworking methods as well as the latest in composite technology and wood joinery.

Most conventional components and fittings have been incorporated into the Renovo bike frames. The head tube and seat tube use aluminum sleeves inside the wood. This allows conventional components to be used in the headset and accommodates the seat post clamp. Most cable routing is inside the frame. One part of the Renovo bikes which required invention and innovation is the bottom bracket.

The bottom bracket is one part of Renovo bikes that does not find a direct counterpart in production bikes. The Renovo bottom bracket shell “hangs” from the bottom of the wooden frame. The threaded aluminum bottom bracket shell is specially treated and bonded to the wood with epoxy with the same technology used to bond together wooden frame pieces. This illustration shows a test device used to measure the force required to pull the shell from the wooden bottom bracket model. The failure strength of this bonded joint was 1100 lbs in a bench pull test of tensile strength.



The actual bike uses the epoxy bond as well as screws through the aluminum shell into a hidden block of ash fitted into the frame for added strength. The plugged holes in the bottom bracket shell visible below allowed placement of the reinforcing screws during construction. The Renovo bottom bracket used on working bikes is modified as shown to accommodate the chain stays of the carbon fiber rear triangle. Ken Wheeler reports that both heavy and strong test riders have ridden Renovo bikes many miles in varied conditions without problems of the bottom bracket or other frame components.



The bottom bracket redesigned for wooden frames


DESIGN AND PRODUCTION
The subtleties of the Renovo frame shape are similar to my Giant OCR all-carbon road bike. Both bikes use ovalized and curved tubing in a compact design with additional buttressing of the tubing at key stress points such as where the top tube joins the seat tube. The finger joint detail can be seen in this image. A subtle curved buttress added to the tubes and joint can be seen below.



The Seat Cluster

Renovo bicycles are made in both standard and compact frame designs. Currently, all bikes sold use a carbon front fork and one-piece carbon rear triangle produced by others. A prototype pursuit bike may be the first Renovo design to use a wooded monocoque design for the entire frame. The preliminary sketch of this pursuit bike includes a strongly curved top tube forming a continuous arc through the seat post, to the rear dropouts. This design exemplifies the ability of wood to remain structurally stiff and light in strongly curved frame sections more so than in any other bicycle frame material.

Both Renovo wood and Giant carbon bicycle frames are designed with the aid of computers to build in desired ride qualities. Unlike metal, wood and carbon are not limited to a particular set of shapes. The computer design is sent to a sophisticated shaping machine which trims wood from the laminated blank half frame and creates the hollow tubes.



Frame halves prior to bonding

ON THE ROAD
My test bike (below) was constructed of pale, laminated bamboo bonded to a dark red bubinga spine; the fork and rear triangle are carbon. The finish was flawless and the bike was a piece of artwork. On the road, I looked down to see the rich color and grain of the wood. It took a moment to wrap my brain around the concept of trusting these thin wooden spars over bumps—and at brisk pace while supporting my 200 lbs—in traffic. Wood simply isn’t supposed to behave this way!



My test bike on the shop floor at Renovo



Laminated bamboo bonded to Bubinga spine


The frame size of my test bike was a bit too small for my 6’1” height so I felt a bit cramped in top tube length. The frame geometry is reminiscent of older European road racing bicycles with more relaxed steering and seat tube angles than criterium bikes. With this geometry came a responsive, but predictable and confident ride without the twitchyness of overly-steep bikes. The big difference came when I stood out of the saddle to climb a hill. The frame was very stiff laterally and did not allow noticeable flex between the cranks and handlebars. I appreciated the adequate toe to front tire clearance when pedaling through a corner, a thoughtful design feature.

On the road, the Renovo was quiet on rough asphalt. My carbon bike has a something of a bull roar sound on rough roads as the vibrations passing through the frame make it behave like a percussion instrument. I could feel the vibrations of the asphalt road transmitted to my hands to a similar degree as with my carbon bike. The vibrations passing through to the seat however, did seem to be reduced. Besides the vibration-dampening quality of wood, the relatively thick wall tubing of the Renovo adds additional mass to absorb vibration compared to a thinner wall tubing designs such as with carbon, steel, or titanium.

My test bike was beautifully set up and operated flawlessly. My bike had a carbon front fork and carbon rear triangle. The stiff and responsive high quality wheelset certainly added to my impression of this bike. The Renovo was set up with a 10-speed Ultegra drivetrain with the exception of FSA Carbon cranks with a compact chain ring set. Where feasible, control cables run within the frame

Pros:
Beauty; first owner of a wooden bike on your block if not your country, renewable as sunshine and photosynthesis, innovative, uses the highest quality and most innovative machining and joinery technology. This bike will attract attention.
While many high-performance bicycles push the limit of light weight with tubing wall thicknesses barely adequate to support a given rider weight for a set amount of time, the Renovo wooden frames achieve light weight and high performance with a more durable thicker-walled frame.

Cons:
With few steel components, Renovo wooden bicycles will not activate magnetic sensors at lighted intersections. Renovo riders, along with their colleagues on carbon, aluminum, and titanium frames can take turns pressing the pedestrian button to get a green light.

Prices, contact information and serious eye-candy are available from Renovo Hardwood Bicycles.