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Pro bike: Marianne Vos' Giant TCX Disc

By:
BikeRadar
Published:
February 02, 2014, 11:16 GMT,
Updated:
February 02, 2014, 11:26 GMT

At 26, Dutch cycling superstar Marianne Vos convincingly won her seventh elite women’s title at the World Cyclocross Championships in Hoogerheide, Holland, on Saturday. Before she did, we got our hands on one of the bikes she used.

Giant’s TCX Disc has become a familiar sight at the front of the men’s field under the fast-starting Lars Van Der Haar, but for the tech-savvy and technical Vos, her decision to use the disc machine was telling. The TCX Disc has already hit the consumer market, some models with a front thru axle, but Vos’s team bike retains conventional quick release skewers, and even though she runs Shimano’s electronic Dura-Ace Di2, her frame doesn’t have either convertible or specific electrical cable routing.

The most prominent feature of Vos’s TCX is the negative-rise stem. Although she rides the smallest frame size available (50cm/S), she still wanted a lower riding position, and thus this stem was the only option. At 85mm it’s an odd size, but the –30 degree angle is even more unusual, and is one Shimano’s PRO component arm don’t currently offer. Fortunately a Giant Taiwanese manufacturer does. A 42cm PRO Vibe 7s bar, tilted back a little gives a position that is super low when riding on the drops, or low and long when on the hoods.

Shimano’s hydraulic road disc system has been widely reported, and is slowly becoming more common. Here, Vos has 140mm rotors front and rear, fitted to Shimano’s as-yet-unnamed road disc wheels, with their 35mm tubular carbon rims, and 28-hole CX75 hubs, laced two cross with black, bladed J-bend spokes.

The drivetrain is Shimano Dura-Ace Di2 with internal battery, and the addition of a pair of Rotor’s oval shaped Q-Rings, in 38/46, necessitating careful placement of the front derailleur to allow for the oval ring shapes. An 11-28 tooth cassette gives a wide range of gears, and the 172.5mm cranks are relatively lengthy for a rider of her 1.69m height, but give some extra leverage, especially useful in the mud.

The bike we featured had Dugast Typhoon tubulars fitted, which are excellent tyres for fast, intermediate conditions, but after the heavy overnight rain, Rhinos were the only practical option from Dugast’s offerings, and Vos had all her bikes swapped to the grippier mud tyres before embarking on her final course recces. Both tyres are 33mm wide, the maximum allowed under UCI regulations, but the TCX frame still has impressive clearance all round.

A Fizik Arione saddle is fitted on to the TCX’s specific carbon seatpost, whose subtly flattened rear prevents misalignment, but also induces a measure of flex too, being nominally sized as 27.2mm diameter. There are a number of neat finishing touches, such as the filled in right side gear cable opening in the down tube, and small plugs that are fitted flush in each of the frame’s bottle cage boss holes for practicality.

For such a small bike with carbon rims and tubulars, we expected a little less overall mass, but its 7.98kg complete with pedals, and the undoubtedly heavier disc brake setup is still very respectable, and clearly didn’t hold Vos back, since she won alone 1’07” ahead of second place. When asked following the race, her mechanic said that she only changed bike three times in the four long laps she completed, attesting to the bike’s mud shedding abilities, and the rider’s talent. With such an effective combination, it would be a brave person who’d bet against Vos continuing her reign next year too.

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