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Pro bike: Lars Boom's Rabobank Giant TCX Advanced SL

By:
James Huang
Published:
April 13, 2011, 11:40 BST,
Updated:
April 13, 2011, 16:17 BST
Race:
Paris - Roubaix
Former cyclo-cross world champion Lars Boom (Rabobank) went to his familiar roots, running a Giant TCX Advanced SL at this year's Paris-Roubaix.

Former cyclo-cross world champion Lars Boom (Rabobank) went to his familiar roots, running a Giant TCX Advanced SL at this year's Paris-Roubaix.

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The modified Giant TCR Advanced SL machines that Rabobank typically uses at Paris-Roubaix can already accommodate big 27mm-wide tubular tires for extra cushioning on the pavé. But for former cyclo-cross world champion Lars Boom, bigger is better.

Boom instead decided to use his familiar Giant TCX Advanced SL carbon 'cross bike, which had more than enough room for the even more voluminous 30mm-wide tubulars he wanted to use to help him float across the cobbles. Team officials wouldn't comment on the exact make and model of tire Boom was using - they clearly weren't sponsor-correct Vittorias - but the tread design and overall appearance suggested to us that they came from Dugast. Team mechanics did say, though, that Boom ran inflation pressures of just 72psi.

Armed with the bigger tires' extra cushioning, Boom also passed over the traditional box-section aluminum tubular wheels of his teammates in favor of Shimano's now discontinued 24mm-deep Dura-Ace carbon tubulars. As a result, Boom's bike actually ended up being a full 500g lighter than other Rabobank bikes with an actual weight as pictured here of 7.39kg (16.29lb) - definitely more in keeping with some of the lighter Paris-Roubaix we profiled this year.

Like a few other Shimano-sponsored riders who normally run Dura-Ace Di2 on their everyday race machines, Boom switched to the mechanical version for Paris-Roubaix despite the system's increased susceptibility to housing contamination and longer shift lever throws. According to team mechanics, Boom felt that Di2's super-short button throws were too sensitive when his fingers were bouncing around on the pavé and didn't want to run the risk of a mis-shift during the race.

Typical Paris-Roubaix tweaks to the otherwise standard Dura-Ace 7900 group include 53/44T gearing (which Shimano now offers in matched sets to retain the stock setup's superb shift performance) and a tight-ratio 11-23T cassette to better suit the flat parcours. Noteworthy is the fact that unlike many other racers that day, Boom went without a chain watcher.

Shimano of course doesn't make Dura-Ace cantilever brakes, though, so Giant and Rabobank instead commissioned lightweight aluminum brakes - anodized in team orange and blue colors - from one of its prototype suppliers in Taiwan.

There's easily a finger's width of room on all sides of the front tire on Lars Boom's (Rabobank) Giant TCX Advanced SL, even with a bulbous 30mm casing.

"These are new prototypes [done by] the same guy who makes the time trial brakes for us (Giant and Rabobank), the "standard" 'cross brakes for the Rabo team, and some other parts and projects with us," said team technical director Andy Wollny. "It's a small Taiwanese company - no big name, but very flexible and always able to help me to make special parts in a short time."

Boom's brakes feature simple dual-aluminum plate construction with no frills like spring covers or fancy hardware to keep the weight low. Ball-joint cartridge holders and slotted arms allow for proper pad placement, though, and tidy set screws are on hand for easy and precise centering. The low-profile configuration also produces more power than the wide-profile brakes Boom usually uses for 'cross, too.

Boom's bike is finished with PRO's Vibe carbon-wrapped stem and PLT Anatomic aluminum handlebar, Shimano Dura-Ace PD-7810 aluminum-bodied pedals, an FSA headset, a fi'zi:k Arione CX saddle, and a pair of Tacx Tao cages.

Boom ultimately finished 12th on the day.

This article first appeared here on BikeRadar.

Full Specifications

Complete bike specifications:

Frame: Giant TCX Advanced SL, size L/56.5cm
Fork: Giant TCX Advanced SL, 1 1/8"-to-1 1/4" tapered
Headset: FSA Orbit integrated, 1 1/8"-to-1 1/4" tapered
Stem: PRO Vibe, 130 x -6°
Handlebars: PRO PLT Anatomic, 42cm (c-c)
Tape/grips: PRO cork
Front brake: Rabobank custom aluminum cantilever by Giant w/ Shimano carbon-specific pads
Rear brake: Rabobank custom aluminum cantilever by Giant w/ Shimano carbon-specific pads
Brake levers: Shimano Dura-Ace STI Dual Control ST-7900
Front derailleur: Shimano Dura-Ace FD-7900-F
Rear derailleur: Shimano Dura-Ace RD-7900
Shift levers: Shimano Dura-Ace STI Dual Control ST-7900
Cassette: Shimano Dura-Ace CS-7900, 11-23T
Chain: Shimano Dura-Ace CN-7900
Crankset: Shimano Dura-Ace FC-7900, 175mm, 53/44T
Bottom bracket: Shimano Dura-Ace SM-7800-P
Pedals: Shimano Dura-Ace SPD-SL PD-7810
Wheelset: Shimano Dura-Ace WH-7850-C24-TU
Front tire: Custom Dugast Paris-Roubaix tubular, 30mm
Rear tire: Custom Dugast Paris-Roubaix tubular, 30mm
Saddle: fi'zi:k Arione CX k:ium
Seat post: integrated
Bottle cages: Tacx Tao (2)
Computer: n/a

Critical measurements:

Rider's height: 1.91m (6' 3")
Rider's weight: 78kg (172lb)
Saddle height, from BB (c-t): 817mm
Saddle setback: 77mm
Seat tube length, c-t: 554mm
Seat tube length, c-c: 543mm
Tip of saddle nose to C of bars (next to stem): 604mm
Saddle-to-bar drop (vertical): 134mm
Head tube length: 175mm
Top tube length: 575mm
Total bicycle weight: 7.39kg (16.29lb)

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