Pro bike: Tom Boonen’s Specialized S-Works Tarmac SL4

Tommeke and Specialized back to their winning ways in Belgium

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Tom Boonen (Omega Pharma-Quick Step) returned to the limelight this past weekend, 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 sponsors, Specialized.

Boonen has been swapping between Specialized’s two 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. 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 1-3/8in diameter to save a few grams. Chainstays are gigantic as well, and as is typical for bicycle design these days, the seatstays are dramatically slimmer to lend a touch of extra comfort and traction.

As is virtually standard these days, tom boonen’s (omega pharma-quick step) specialized s-works tarmac sl4 is built with generously proportioned chainstays: as is virtually standard these days, tom boonen’s (omega pharma-quick step) specialized s-works tarmac sl4 is built with generously proportioned chainstays
Daniel Benson/

Boonen’s Tarmac SL4 has generously proportioned chainstays

Boonen’s Tarmac SL4 sports an 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 call it “60 Pro”. The top tube length roughly corresponds to the largest stock 61cm size but the head tube 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 for a Zipp model (Zipp didn’t offer Boonen’s preferred 140mm length until recently).

Tom boonen (omega pharma-quick step) is one of the latest pros to get upgraded to sram’s new red 2012 group:
SRAM Road Sports

Boonen is one of the latest pros to get upgraded to SRAM’s new Red 2012 group.

“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’re 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 is the front derailleur, since SRAM have 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.

Tom boonen (omega pharma-quick step) recently replaced his temporary fsa stem with this 140mm-long zipp service course sl model. note the way team mechanics have attached the computer mount:
SRAM Road Sports

This temporary FSA stem has now been replaced with Zipp’s new 140mm-long Service Course SL model

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’re called S-Works and it’s our first approach to a self made tire. We strongly believe that there’s a lot to do in this area. It’s an important piece of equipment that’s never developed much. We’ve 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 have downsized the lower steerer diameter from 1-1/2 to 1-3/8in on the latest tarmac: specialized have downsized the lower steerer diameter from 1-1/2 to 1-3/8in on the latest tarmac
Daniel Benson/

Specialized are providing teams with their own S-Works tubular tires for the first time this season

Specialized have 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 1-3/8in 
  • Stem: Zipp Service Course SL, 140mm x -6° 
  • Handlebar: Zipp Service Course SL, 44cm (c-c) 
  • Tape: 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: Specialized S-Works tubular 
  • Rear tire: Specialized S-Works tubular 
  • Saddle: Specialized Body Geometry S-Works Chicane 
  • Seatpost: Zipp SLSpeed 
  • Bottle cages: Tacx Tao 
  • Computer: Garmin Edge 500

Critical measurements

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  • Rider’s height: 1.92m (6ft 4in) 
  • 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