BQ 21 (Autumn 2007)

Vol. 6, No. 1

Wind Tunnel Testing of Real-World Bicycles

Are wider tires less aerodynamic? What happens if you lower your stem by 20 mm? Are handlebar bags more aerodynamic than saddlebags? What about fenders? Jackets? Fairings? Which is the most aerodynamic riding position for downhill riding? To answer all these questions and more, we spent two days in the wind tunnel. Some of the results confirmed what we believed all along (bulky jackets act like parachutes), while others were surprising (wider tires are no significantly less aerodynamic than narrow ones).

We also visited TA, the famous French component maker and interviewed the the daughter and son-in-law of the founder, Georges Navet. The TA story is fascinating, and it was told here for the first time, illustrated with beautiful drawings of TA’s components by Daniel Rebour.

Aldo Ross explains in detail how the fiendishly complex Campagnolo Paris-Roubaix rear derailleur works. It uses a single lever to open the rear quick release, engage a shifter fork that moves the chain to another sprocket, and then rotates the axle so that the chain runs with just the right tension (a little slack to reduce the load on the hub and bottom bracket bearings). Detailed photos show the mechanism, and after reading this article, derailleur expert Frank Berto wrote to us: “Finally, I understand how the Paris-Roubaix works!”

In 1966, Maurice Macaudière and Roger Demilly rode the 1200 km of Paris-Brest-Paris in a record-setting 44 hours. Macaudière’s timeless report from that adventure was translated into English and reprinted for the first time. Going back further in time, Philip Tooth rode an original 1865 Michaux Boneshaker. He reports that the iron-shod wheels slip easily on pavement, but work fine on gravel roads!

Our test bike also works well on gravel roads: a Bilenky 650B randonneur is one of the first modern bikes influenced by the classic machines of the French constructeurs.