Pro Bike: William Bonnet’s BBox Colnago Cross Prestige

Full-blown 'cross chassis for Paris-Roubaix

The UCI technical rule mandating production-only gear for riders in competition has prompted more riders this year to use full-blown cyclo-cross chassis to tackle the cobbles, in contrast to the often Frankenstein-like custom creations created in years past.


One such rider is BBox-Bouygues Telecom rider William Bonnet.

Even though the weather forecast is calling for good conditions this Sunday, the pavé still places greater demands than what most standard road fare can handle. 

As compared to Bonnet’s usual Colnago CX-1, the Cross Prestige he intends to use for Paris-Roubaix boasts a longer wheelbase and slightly more relaxed angles for more stable handling, a taller bottom bracket for additional clearance (several sections of pavé are notoriously crowned), and most importantly, plenty of room to run high-volume tubular tyres without fear of them clogging up with mud.

Top-mount brake levers usually reserved for ‘cross let bonnet adjust his speed while bouncing along on the cobbles.:
James Huang/BikeRadar

Top-mount brake levers usually reserved for ‘cross let Bonnet adjust his speed while bouncing along on the cobbles

Naturally, the ‘cross-specific frame and greater clearances also dictate the use of cantilever-type brakes but Bonnet’s TRP EuroX Carbon arms don’t actually add any weight as compared to the Campagnolo Record ones that came off – and in fact, they may even be lighter were it not for the supplemental Cane Creek Crosstop levers mounted on the FSA Wing Pro Compact bars. Matching TRP Inplace Adjust pad holders allow for proper toe-in adjustment for better braking, too, though team mechanics did manage to jam Campagnolo brake blocks into the Shimano-specific slots.

Top tube cable routing will protect the lines from mud and debris.:
James Huang/BikeRadar

Top tube cable routing

Other bits that may prove beneficial in case of muddy conditions include the top tube-routed cables that should help maintain shifting performance and the custom brazed chain watcher to help keep Bonnet moving forward on the cobbles.

Bonnet’s gearing is standard-issue Paris-Roubaix with 53/44T chainrings and a relatively tight 11-25T cassette.

It’s worth pointing out that despite the beefiness of a ‘cross frame and tougher bits, Bonnet’s Cross Prestige weighs just 7.66kg (16.89lb).

Since bonnet’s ‘cross bike is intended for big knobbies, there’s more than enough clearance for big road tubulars with room to spare.:
James Huang/BikeRadar

Lots of room to spare for bigger tyres here

Riders often reserve such special machines just for Paris-Roubaix but Bonnet actually raced his Cross Prestige at the preceding Tour of Flanders and Scheldeprijs races as well, presumably to log as many hours as possible on it in competition before the big day.

Campagnolo Bora Ultra deep-section carbon tubulars and narrow Hutchinson tyres were installed the morning of Scheldeprijs (which is pan-flat from start to finish and with virtually no cobbles) but we fully anticipate something more traditional before Sunday’s race sets off from Compiegne, France.

Complete bike specifications

  • Frame: Colnago Cross Prestige, size 54s
  • Fork: Colnago cyclo-cross carbon
  • Headset: Colnago integrated
  • Stem: FSA OS-115, 13cm x -17°
  • Handlebars: FSA Wing Pro Compact, 44cm (c-c)
  • Tape/grips: Colnago cork, double wrapped
  • Brakes: TRP EuroX Carbon with Campagnolo pads
  • Brake levers: Campagnolo Record Ergopower Ultra-Shift 11s w/ Cane Creek Crosstop top-mount levers
  • Front derailleur: Campagnolo Chorus 11s
  • Rear derailleur: Campagnolo Record 11s
  • Shift levers: Campagnolo Record Ergopower Ultra-Shift 11s
  • Cassette: Campagnolo Record 11s, 11-25T
  • Chain: Campagnolo Record 11s
  • Crankset: Campagnolo Record Ultra-Torque ST, 175mm, 53/44T
  • Bottom bracket: Campagnolo Record Ultra-Torque
  • Pedals: Time RXS steel
  • Wheelset: Campagnolo Bora Ultra tubular
  • Front tire: Hutchinson tubular
  • Rear tire: Hutchinson tubular
  • Saddle: Prologo Scratch Pro TR
  • Seat post: Colnago carbon
  • Bottle cages: Elite Ciussi Gel

Critical measurements

  • Rider’s height: 1.85m (6′ 1″)
  • Rider’s weight: 78kg (172lb)
  • Saddle height, from BB (c-t): 785mm
  • Saddle setback: 80mm
  • Seat tube length, c-t: 580mm
  • Seat tube length, c-c: 540mm
  • Tip of saddle nose to C of bars (next to stem): 602mm
  • Saddle-to-bar drop (vertical): 110mm
  • Head tube length: 143mm
  • Top tube length: 565mm
  • Total bicycle weight: 7.66kg (16.89lb)

For more news on Colnago, visit the Colnago channel on