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Pro bikes, January 31, 2008

Katie Compton's Primus Mootry

Photo ©: Ben Atkins

'Old Glory' the tool for new glory

By Ben Atkins

Compton's frame is made up of a scandium rear end and 'lugs'
Photo ©: Ben Atkins
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The head tube is decorated in Compton's national flag
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No-nonsense welds where the main tubes meet
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Whereas the front end of the frame is carbon for extra comfort
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The bridgeless chain stays
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Top-routed cables
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Edge Composites provides Compton with rims
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Katie Compton is enjoying her most successful cyclo-cross season to date. She has proudly paraded her US national champion's jersey - which she won for a fifth successive time this season - on many podiums, including the top step at three World Cups; Koksijde in Belgium, and Nommay and Roubaix in France. As one of the big favourites for this weekend's UCI World Championships in Hoogerheide, the Netherlands, Compton is hoping to ultimately trade in her stars-and-stripes jersey for her first rainbow one.

The similarly red, (sort of) white and blue Primus Mootry frames that Compton has been using to take on the best riders in Europe this winter have been a familiar sight to onlookers but they are not only the identical models as what she rode in last season's campaign, they're the same frames. According to Compton, she and husband/trainer Mark Legg decided that they came out of a tough season of mud and sand good enough to face yet another - a good sign of their durability in contrast to some 'one season only' builds.

Primus Mootry principal Joe DePaemelaere has been building the 'cross star's custom frames since the fall of 2005, though the unique multi-material one seen here isn't in the company catalogue. Compton started out on a full scandium alloy frame at first but she and DePaemelaere eventually decided that bonding carbon fibre centre sections into the front triangle would add a little more compliance.

"These are unique frames for Katie. I don't offer them as a model," said DePaemelaere. "Katie wanted something a little more comfortable than her previous full-scandium frames. The scandium/carbon frames are actually a few grams heavier than the alloy frames, but the added comfort negates that. Now we are looking to shave the weight on the frame, but keep the comfort offered by the carbon."

Otherwise, the moderately sloping geometry is fairly standard save for a slightly steeper than usual seat tube, which allows the former mountain biker and Paralympic tandem pilot to get forward over the front of the bike.

Primus Mootry supplies Compton with frames, although as she isn't technically a member of the factory team she is able to pick and choose her components based on her own preferences - as well as those who will offer her sponsorship. For this reason, Compton has one of the most eclectic setups in the elite circuit, and while the frames are the same as those used last year, virtually everything else is different.

Edge Composites supplies the carbon frame tubing but its support extends much further for this season as it also now supplies Compton with its new all-carbon 'cross fork and deep-section carbon tubular wheels. According to Edge, its proprietary net moulding process allows it to make the fork exclusively from carbon all the way to the dropouts for a feathery 450g claimed weight but also impressive durability and an "uncompromising ride quality."

Likewise, Edge moulds the spoke holes directly into its 68mm-deep carbon tubular rims so as to eliminate the need for drilling and to preserve fibre strength. On this particular occasion she had a top-level 1.0 wheel on the front and a slightly heavier - and tougher - 2.0 on the rear, but we noticed that during many races she uses a 1.0 at both ends.

Both are laced to ultralight, ceramic-equipped DT Swiss 190 hubs with bladed stainless steel spokes held on with a pair of Spin Stix from USE. With a "double start" thread the British company claims that these are quicker and easier to use than cam skewers, and with titanium axles come in at just 55g per pair. Glued to the rims are Challenge Grifo 32 tubulars; the rear one with a standard cotton casing and the front with a smoother rolling and slightly lighter silk one.

The most obvious change from Compton's set-up of last season is the switch she has made from Campagnolo to Shimano Dura-Ace 7900. This latest iteration of Shimano's flagship road package is rare even at this elite level of the sport (and that includes the big stars like Sven Nys) though Compton reportedly had to go out and buy her three groupsets with her own money. Possibly because of this, many of the logos on the new components are covered either with tape or a sticker of someone who does pay her to use its products - namely Enduro, which provides its ceramic ZERØ bottom bracket and front and rear derailleur pulleys.

Spinning on those ceramic bearings is the biggest break from that 7900 groupset, namely an SRM power meter based on a Dura-Ace 7800 chainset (SRM hasn't yet produced a version with 7900 arms). Compton has become one of the many riders who feel that the plethora of useful data that racing with a power meter provides can outweigh the weight penalty it brings.

Other breaks from a complete Shimano ensemble include a gold-coloured KMC X10-SL chain and a pair of Crankbrothers Eggbeater 2ti pedals - the same as she used last season.

Braking duties come courtesy of TRP with its EuroX Mag cantilever brakes - which are actually a claimed 6g per wheel lighter than the carbon ones - and RL950 top-mount levers. Compton fits the magnesium brake arms with longer cartridge pad holders, though, presumably to put more brake block on the rim for surer stopping.

Compton has long been a devout fan of Deda Newton aluminium handlebars but finally made the switch to carbon this year with her new Zipp SLC2 bars. In addition to being substantially lighter than its forebear, Compton feels the "short and shallow" bend is easier to handle while in the drops and the careful construction is seemingly able to withstand the abuse of 'cross. Holding the bars tight is a Rotor SX stem, whose +2.5deg angle allows for a shorter steerer tube and virtually no headset spacers atop the Chris King NoThreadset, relative to the -10deg Thomson she used last year.

While Thomson has been replaced at the front of the bike, it has been retained at the rear in the shape of a Masterpiece seatpost. This and the WTB Silverado saddle is one of the few pieces of kit that have been kept from last year's bike.

With its stars and stripes livery and its eclectic mix of components Compton's bike is one of the most conspicuous bikes out there and there's no mistaking who it belongs to. If all goes to plan this weekend Compton may end up riding these frames for yet another season, though a new paint job - with different coloured stripes - might be in order.


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Images by Ben Atkins/Cyclingnews.com

Full specification

Frame: Primus Mootry custom (carbon fibre tubes/scandium lugs)
Fork: Edge Composites Cross

Critical measurements
Rider's height: 1.65m (5' 5"); Weight: 63.5kg (140lb)
Seat tube length, c-c: 478mm
Seat tube length, c-t: 520mm
Saddle height, from BB (c-t): 687mm
Tip of saddle nose to C of bars (next to stem): 462mm
C of front wheel to top of bars (next to stem): 615mm
Top tube length: 525mm (horizontal)

Front brake: TRP EuroX Magnesium
Rear brake: TRP EuroX Magnesium
Brake levers: Shimano Dura-Ace STI Dual Control ST-7900
Front derailleur: Shimano Dura-Ace FD-7900-F
Rear derailleur: Shimano Dura-Ace RD-7900-SS
Shift levers: Shimano Dura-Ace STI Dual Control ST-7900
Cassette: Shimano Dura-Ace CS-7900, 12-25T
Chain: KMC X10-SL
Crankset: Dura-Ace Compact (w SRM), 175mm, 44/34T plus TA Alize chainrings
Bottom bracket: Enduro ZERØ Blue

Front rim: Edge Composites Tubular 1.0 68mm
Rear rim: Edge Composites Tubular 2.0 68mm
Front hub:
DT Swiss 190
Rear hub:
DT Swiss 190
Front tyre:
Challenge Grifo 32 Seta tubular
Rear tyre: Challenge Grifo 32 tubular

Bars: Zipp SLC2, Short/Shallow bend, 42cm (c-c)
Stem: Rotor SX, 120mm x -2.5º
Headset: Chris King NoThreadset
Tape/grip: Cork

Pedals: Crankbrothers Egg Beater 2ti
Seat post: Thomson Masterpiece
Saddle: WTB Silverado

Total bike weight: 7.81kg (17.2lb)