Boonen's goodbye bike: Pro-only front suspension for Paris-Roubaix

Tom Boonen's name and photos have been plastered on the roads, stores, restaurants and hand-held signs across Belgium and into northern France all week, as the cobble-racing legend prepares to retire after his final Paris-Roubaix Sunday. Here is a look at the bike he will race from Compiegne north to the aging outdoor velodrome of Roubaix.

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On Monday, BikeRadar reported on the pro-only edition of the new Specialized Roubaix that Boonen raced at the Tour of Flanders, and which world champion Peter Sagan raced Wedesday at Scheldeprijs. The immediately obvious differences to the consumer bike are the long-and-low geometry, the direct-mount brakes and — if you put a hand on it — the stiffer spring in the Future Shock suspension cartridge underneath the stem.

At closer inspection, Boonen's extreme geometry is also noteworthy, too. For instance, 38mm center-to-center handlebars for a 192cm / 6'3" man?

Specialized Racing's Chris D'Alusio explained to BikeRadar today that Quick Step and Specialized worked together to test a variety of different springs for racing on the cobbles. The final product was a stiff, progressive spring that ramps at both ends of the travel; it's harder to initially engage and harder to bottom out than any of the three stock springs, but relatively softer in the middle of the 20mm of travel, like a parabola.

The hits from the cobbles are so jarring that the stiffest of the stock springs bottomed out too quickly, D'Alusio said.

Boonen has Specialized's new Hell of the North tubulars in both 28mm and 30mm, but it is not yet certain which width he will race.

The Shimano Dura-Ace direct-mount brake calipers on the Roubaix offer plenty of clearance for the fat tubulars.

The consumer models of the new Roubaix are all disc brake bikes. Normal UCI rules state that bikes must be approved by the UCI and available for sale to the public in order to be sold. Specialized representatives said that since this new pro-version bike is only a change in brake type (and geometry), that the UCI was okay with it.

Team members also said that the primary driver for using rim brakes for Paris-Roubaix is so riders can get a quick wheel change anywhere on the course — from team cars, neutral support, roadside mechanics or even fans. Punctures are common at the rough cobbled race, and the top riders don't want to chance getting caught out with a potentially hard-to-change disc wheel.

Check out the gallery above for a closer look.