Pro bike: Tom Boonen's Omega Pharma-QuickStep Specialized S-Works Tarmac SL4

Tom Boonen (Omega Pharma-QuickStep) returned to the limelight this past weekend – in a good way – taking impressive victories at the E3 Prijs-Vlaanderen and Gent-Wevelgem. Boonen likely isn't the only one smiling, though, as the victories also mean fresh bragging rights for his long-time bike sponsor, Specialized.

Boonen has been swapping between both of Specialized's flagship S-Works road chassis – the aero McLaren Venge and the lighter and stiffer Tarmac SL4 – and he's found success on both already. Boonen won Sunday's Gent-Wevelgem on the Venge but we've profiled his Tarmac here, which he used in Friday's E3 Prijs-Vlaanderen.

The bikes' disparate design language is immediately obvious from first inspection. Whereas the Venge is nipped and tucked to decrease drag, the Tarmac SL4 makes virtually no concessions in the name of reducing frontal area with gargantuan, nominally round main tube cross-sections plus an hourglass-profile head tube that now boasts a slightly slimmer 1 1/8-to-1 3/8" diameter to save a few grams. Chain stays are gigantic as well and as is typical for modern bicycle design these days, the seat stays are dramatically slimmer to lend a touch of extra comfort and traction.

Just as Specialized had done in years past, Boonen's Tarmac SL4 also sports a uniquely aggressive geometry to suit his uniquely long and low riding position. Once a purely custom build – in fact, the critical numbers are virtually identical to his Paris-Roubaix machine from 2009 – Specialized now calls it "60 Pro". The top tube length roughly corresponds to the largest stock 61cm size but the head tube length falls in between that of the stock 56cm and 58cm frames – a setup few amateurs could even tolerate, let alone prefer. Handlebar drop on Boonen's bike is a similarly aggressive 120mm.

We shot the bulk of these images the day before Boonen's second-place finish at Omloop Het Nieuwsblad and while the frame and Zipp carbon tubular wheels have remained constant, the former Belgian champion has received a number of upgrades since then. Old Red has been replaced with the newer, lighter, and more functionally refined version, and the unbranded FSA stem has been traded in favor of a proper Zipp model (Zipp didn't offer Boonen's preferred 140mm length until recently).

"We introduced Boonen to Red 2012 in Belgium prior to Paris-Nice [where he won stage 2 – Ed.]," said SRAM's European road sports representative, Ben Raby. "As we are slowly outfitting teams now with new Red, he was one of our key athletes heading into the Classics. He responded very well to the new hood design and was very impressed by the braking performance and new feel. He wanted it immediately."

The one exception to the complete Red switchover, though, is the front derailleur since SRAM has yet to finalize new Red rings for Boonen's team-issue Specialized carbon cranks. According to Raby, that development period is nearing completion so we expect to see the trick Yaw-equipped front derailleur on Boonen's bike soon enough.

Also noteworthy is Boonen's tire choice. Quick Step once openly used Veloflex tubulars badged with Specialized hot stamps but according to team liaison Simone Toccafondi, Boonen and the rest of the team are now on proper house-designed rubber following the company's successful 'cross tubular debut.

"Finally, this year we have our own made and designed tubulars," Toccafondi told BikeRadar. "They are called S-Works and it is our first approach to a self made tire. We strongly believe that there is a lot to do in this area. It is an important piece of equipment that has never developed much in the years. We have worked closely with the team to determine the right compound, width and thread. We came up with a great result in terms of rolling resistance and durability."

Specialized has a history of unveiling special builds for Boonen at Paris-Roubaix and we'll be on the lookout as the race approaches. Another win for Boonen on another Specialized bike debut? Lady luck has shined on the big 'S' in the past but we'll just have to wait and see.

Complete bike specifications

Frame: Specialized S-Works Tarmac SL4, custom geometry
Fork: Specialized S-Works FACT Carbon
Headset: Integrated 1 1/8-to-1 3/8"
Stem: Zipp Service Course SL, 140mm x -6°
Handlebars: Zipp Service Course SL, 44cm (c-c)
Tape/grips: Specialized Roubaix
Front brake: SRAM Red 2012 w/ Zipp Tangente Platinum Pro pads
Rear brake: SRAM Red 2012 w/ Zipp Tangente Platinum Pro pads
Brake levers: SRAM Red 2012 DoubleTap
Front derailleur: SRAM Red Black
Rear derailleur: SRAM Red 2012
Shift levers: SRAM Red 2012 DoubleTap
Cassette: SRAM PG-1070
Chain: SRAM PC-1091
Crankset: Specialized FACT Carbon, 177.5mm, 53/39T
Bottom bracket: Specialized integrated OS
Pedals: Look KéO Blade
Wheelset: Zipp 404 Tubular
Front tire: tubular
Rear tire: tubular
Saddle: Specialized Body Geometry S-Works Chicane
Seat post: Zipp SLSpeed
Bottle cages: Tacx Tao
Computer: Garmin Edge 500

Critical measurements

Rider's height: 1.92m (6' 4")
Rider's weight: 82kg (181lb)
Saddle height, from BB (c-t): 815mm
Saddle setback: 115mm
Seat tube length, c-t: 580mm
Seat tube length, c-c: 535mm
Tip of saddle nose to C of bars (next to stem): 660mm
Saddle-to-bar drop (vertical): 120mm
Head tube length: 175mm
Top tube length: 602mm

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