Pro Bike: Tom Boonen’s Specialized S-Works Roubaix SL2 custom

The QuickStep rider gets a custom rig for Hell on Sunday

Just how much is one rider worth to a bicycle sponsor?  If that rider is Belgian superstar Tom Boonen and that company is Specialized, the answer is: quite a lot.


Specialized had already developed one custom S-Works Tarmac SL2 geometry late in 2007 for Boonen’s tall build with a longer top tube and shorter head tube.  This not only allows him to stretch out more to develop full power but according to Boonen, also protects his sensitive lower back from injury. 

Unlike metallic frames, creating an altered geometry on a molded carbon frame requires more than simply adjusting mitre points and weld jigs though – it entails careful engineering work to adjust lay-up schedules for the various plies and, of course, the creation of the mould itself.  Add it all up and it’s not exactly an inexpensive endeavour – all for one guy (well, two if you also include former teammate Gert Steegmans who happened to need the same fit).

Come Classics season 2008 and Specialized had to repeat the process again since the smoother and more relaxed handling of their Roubaix platform was perfect for the demanding cobbles but once again, the stock geometry didn’t suit Boonen’s physique.  In this case, the dimensional changes of the custom front end are even more substantial since that frame normally comes with an even longer head tube than on the Tarmac but the end result is still essentially the same. 

Short of a keen eye and a tape measure, there’s no visual indication that this roubaix uses an entirely different front end than usual.: short of a keen eye and a tape measure, there’s no visual indication that this roubaix uses an entirely different front end than usual.
James Huang

All of the Roubaix’s key features carry over intact, including the vibration damping Zertz viscoelastic inserts, lengthened chain stays, slacker head tube angle, increased fork rake, longer wheelbase, and the more stable handling that ultimately results.  As a result, Boonen’s custom S-Works Roubaix SL2 effectively provides the same fit as on his Tarmac – save for a slightly taller bar position owing to the slacker head tube angle – but the ride and handling of a Roubaix.  In contrast to his once-custom Tarmac though – now included in the production sizing scheme – Specialized have yet to offer this geometry to the public.

Boonen has now captured his third Paris-Roubaix title this Sunday on essentially the same frameset as last year, albeit with a slightly different build kit from before.

Last year’s Campagnolo Record gear has now been replaced by the latest Record 11 kit, including brand-new matched 53/46T chainrings developed just for the occasion and an 11-23T cassette for tight spacing throughout the range.  For whatever reason, Boonen has stuck with the 10-speed Record generation for his crankset and front derailleur though.  Considering the close-ratio rings and the custom inner chain guard, it’s unlikely even Paris-Roubaix’s worst cobbles will launch Boonen’s chain off track.

Boonen prefers fsa’s new ergo semi-anatomic bend and rotates them a little further forward on his roubaix than on his usual tarmac.: boonen prefers fsa’s new ergo semi-anatomic bend and rotates them a little further forward on his roubaix than on his usual tarmac.
James Huang

As is common with most Paris-Roubaix racers, Boonen’s bars are heavily padded – presumably with Specialized’s BG SuperPhat material – but only up top, which makes sense considering that is where his hands will mostly be while on the cobbles.  As compared to his Tarmac SL2 though, the bars are also rotated markedly higher for a slightly more upright position.

The drops are similarly large in diameter but here team mechanics have added a “secret” hard layer of material beneath the tape.  The resultant “D”-shaped profile fits better in Boonen’s hands and apparently provides a better grip when it comes time to sprint.

Any guesses as to the make of these tubulars?: any guesses as to the make of these tubulars?
James Huang

Wheels are of the usual box-section aluminium tubular variety usually found at Paris-Roubaix, built with unmarked DT Swiss 240s hubs, Ambrosio rims and Sapim spokes laced three-cross and secured with brass nipples.  The corresponding 25mm-wide (actual measurement) file tread tires bear no markings whatsoever but are clearly handmade – we’re guessing FMB based on what he used last year.

If boonen gets his way, another tornado will sweep through the roubaix velodrome.: if boonen gets his way, another tornado will sweep through the roubaix velodrome.
James Huang

Total weight for the complete bike is 8.3kg (18.3lb) – a merely average figure for a typical road racer but a good indicator of the extra strength included therein that will be needed to carry Boonen to the finish.

One man, two molds, lots of time, and lots of money, but also two stunning victories at Paris-Roubaix to show for it.  With three cobbles now in Boonen’s trophy case and who knows how many more are yet to come, we dare say that even Specialized’s bean counters will say that it was very much worthwhile.

Complete bike specifications           

  • Frame Specialized S-Works Roubaix SL2, custom 61cm ‘Pro’ geometry       
  • Fork Specialized S-Works Roubaix SL2       
  • Headset Cane Creek integrated       
  • Stem FSA custom, 140mm x -6°      
  • Handlebars FSA Energy New Ergo, 44cm (c-c)    include width in cm, center-to-center   
  • Tape/grips  Specialized BG Roubaix w/ BG SuperPhat padding on tops and custom shaping on drops       
  • Front brake Campagnolo Record D-Skeleton       
  • Rear brake Campagnolo Record D-Skeleton       
  • Brake levers Campagnolo Record Ergopower Ultra-Shift 11s       
  • Front derailleur Campagnolo Record 10s       
  • Rear derailleur Campagnolo Record 11s       
  • Shift levers Campagnolo Record Ergopower Ultra-Shift 11s       
  • Cassette Campagnolo Record 11s, 11-23T       
  • Chain Campagnolo Record 11s       
  • Crankset Campagnolo Record Ultra-Torque ST 10s, 177.5mm, 53/46T       
  • Bottom bracket Campagnolo Record Ultra-Torque         
  • Pedals Look KeO Carbon       
  • Rims Ambrosio tubular 32h       
  • Front hub DT Swiss 240s 32h       
  • Rear hub DT Swiss 240s 32h       
  • Spokes Sapim 14/15g w/ brass nipples 3x front and rear       
  • Front tyre Tubular, 25mm       
  • Rear tyre Tubular, 25mm       
  • Saddle Selle San Marco Regal       
  • Seat post carbon       
  • Bottle cages Specialized S-Works Rib Cage Carbon       
  • Computer n/a       
  • Other accessories custom front chain guard              

Critical measurements           

  • Rider’s height 1.92m (6′ 4″)    
  • Rider’s weight 80kg (176lb)    
  • Saddle height, from BB (c-t) 799mm    
  • Seat tube length (c-t) 583mm    
  • Seat tube length (c-c) 532mm   
  • Tip of saddle nose to C of bars (next to stem) 645mm    
  • C of front wheel to top of bars (next to stem) 588mm    
  • Handlebar drop 120mm    
  • Head tube length 175mm    
  • Top tube length 595mm (actual)
  • Total bicycle weight 8.3kg (18.3lb)  

Follow this Sunday’s Paris-Roubaix live on