This article first appeared on BikeRadar.
John Degenkolb (Trek-Segafredo), winner of the 2015 Paris-Roubaix, will be racing this year's edition of the Hell of the North aboard a Trek Domane equipped with a Shimano Ultegra RX805 clutch rear derailleur, among other modifications.
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Degenkolb and other members of his Trek-Segafredo squad have been testing out the brand-new Shimano road clutch derailleur ahead of Paris-Roubaix. BikeRadar tailed the team on its Tour of Flanders recon ride to film Degenkolb trying out the Ultegra RX on his Domane.
Trek-Segrafredo technical director Matt Shriver said he had been asking Shimano for a clutch rear derailleur for two years. Just like with Shimano's Shadow Plus clutch derailleur for mountain bike, the Ultegra RX is designed to reduce unwanted chain movement.
For Shriver, there are two main benefits to the clutch at Paris-Roubaix: reducing or eliminating the possibility of dropping the chain, but also allowing for a smoother power application from the rider.
The Ultegra RX805 has a manual on/off switch, so there is no changing settings mid-race.
When this lever is flipped up to the ON position, the clutch is engaged to greatly reduce movement at that pivot, effectively keeping the chain more stable
That said, Degenkolb has changed bikes mid-race at Roubaix before, and will likely do so again. Although the 250km contest has more than 50km of pavé, all the sectors come in the latter half of the race; the first half is a normal, flat-out road race on smooth roads. Last year Degenkolb started on a Madone aero bike with aero wheels, then switched to his Domane with fat tubulars for the second half.
Another unusual change for Degenkolb's Roubaix bike is the shorter cranks. Instead of his regular 172.5mm Dura-Ace cranks, Degenkolb is running 170s. The change was the result of pressure-mapping testing Trek-Segafredo did with gebioMized on Belgian cobbles. They found that Degenkolb's stability on the saddle improved on the cobbles (at the same power) by shortening the cranks.
After testing with gebioMized and Trek, Degenkolb opted to run 170mm instead of his normal 172.5mm cranks for the cobbles
Another less dramatic but equally important change: bottles cages with a tenacious grip. While Bontrager has 19g XXX cages (that retail for $80), Trek-Segafredo uses $14 Bat Cages, which are designed for cyclocross and gravel. Turns out that keeping the bottles on the bike is more important to Roubaix competitors than saving 60g.
Mechanic's handiwork keeps the junction-box mount tidy