Pro bike: Brent Bookwalter's BMC TimeMachine TM01, May 8, 2014

Wider tires invade the final front

This article first appeared on BikeRadar.

American rider Brent Bookwalter (BMC) will serve as a key lieutenant to team captain Cadel Evans as he seeks another overall win at the Giro d'Italia. That three-week campaign starts with a team time trial around downtown Belfast in Northern Ireland, where every rider will use BMC's sleek TimeMachine TM01.  Unfortunately, for Bookwalter, he took a tumble during training in Belfast, just a few hours before he was due to line-up in the opening team time trial stage.

We've inspected the TM01 several times since its introduction in 2011 and three years later, it's still a visually striking and utterly contemporary-looking machine with its aggressive and angular lines, cleverly hidden front and rear brakes, sleek (and extremely narrow) external fork steerer, and highly integrated cockpit setup.

Despite its overuse, the term "looks fast standing still" certainly applies here.

The trend we've seen with pro riders resorting to smaller-than-typical frame sizes carries over to the time trial side, too, at least in this case. Despite standing 1.80m (5ft 11in) tall, Bookwalter has opted for BMC's smallest available TM01 chassis. This keeps the base bar height very low and shortens the front center but also requires a generous stack of spacers beneath the armrests. 36mm of extra stem extension helps push the grips further out, too.

More interesting, however, is Bookwalter's 25mm-wide Continental tubular tires – a size that until very recently would never have been considered for time trials where rolling resistance and aerodynamics are of paramount importance. Rolling weight isn't nearly as critical for most time trials, though, and as the pros are increasingly realizing, the wider tires are actually yielding lower times along with other ancillary benefits such as increased cornering grip, which could prove critical depending on road conditions for the opening team time trial.

"The riders thought it would be much slower but it's the exact opposite," team mechanic Jürgen Landrie told Cyclingnews. "It's faster, more comfortable, and we get fewer flats."

Landrie did stress, however, that the aerodynamic benefits are only realized when those wider tires are paired with correspondingly wider rims. In this case, both the PRO Textreme Carbon rear disc and Shimano Dura-Ace WH-9000-C75-TU deep-section front wheel boast compatible 24mm-wide cross-sections.

All of this component integration may look impressive when all is said and done but – as is often typical for most top-end TT rigs – it takes quite a bit of work to get to that point. According to Landrie, each of the team's TM01s can take even a seasoned team mechanic a full day to build and tune to race readiness. When you consider that there are 28 riders on the WorldTour squad plus the fact that many of the riders have more than one time trial machine at their disposal, those days add up quickly.

If all goes well for Bookwalter and the rest of his BMC team, though, all of that time will be very well spent and will feel like a distant memory once the champagne starts to flow.

Full Specifications

Complete bike specifications

Frame: BMC TimeMachine TM01, size small
Fork: BMC Aero Hinge
Headset: BMC integrated
Stem: BMC integrated w/ 36mm spacers
Handlebar: 3T Brezza II Team, 40cm (c-c)
Tape: fi'zi:k
Front brake: BMC integrated with Shimano carbon-specific pads
Rear brake: BMC integrated with Shimano carbon-specific pads
Brake levers: Shimano Dura-Ace Di2 ST-9071
Front derailleur: Shimano Dura-Ace Di2 FD-9070
Rear derailleur: Shimano Dura-Ace Di2 RD-9070
Shift levers: Shimano Dura-Ace Di2 ST-9071 and SW-R671
Cassette: Shimano Dura-Ace CS-9000, 11-25T
Chain: Shimano Dura-Ace CN-9000
Crankset: SRM PowerMeter Shimano DA7900, 175mm, 54/42T
Bottom bracket: FSA BB-ALM3
Pedals: Shimano Dura-Ace SPD-SL PD-9000
Front wheel: Shimano Dura-Ace WH-9000-C75-TU
Rear wheel: PRO Textreme Carbon Disc tubular
Front tire: Continental Competition ProLtd ALX tubular, 25mm
Rear tire: Continental Competition ProLtd ALX tubular, 25mm
Saddle: fi'zi:k Ares, carbon shell, k:ium rails
Seatpost: BMC Aero Post
Bottle cages: Elite Sior Mio (1)
Other accessories: SRM PowerControl 7 computer, RaceWare Direct Raised SRM TT computer mount

Critical measurements

Rider's height: 1.80m (5ft 11in)
Rider's weight: 70kg (154lb)
Saddle height from BB, c-t: 754mm
Saddle setback: 52mm
Seat tube length (c-t): 503mm
Tip of saddle nose to center of bars (next to stem): 560mm
Saddle-to-elbow pad drop: 125mm
Frame stack: 480mm
Frame reach: 393mm
Weight: 8.67kg (19.11lb, with computer, without bottle)

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