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Pro bike: Geoff Kabush's Rocky Mountain Solo Carbon prototype

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Geoff Kabush (Maxxis-Rocky Mountain) is racing this season on a prototype carbon 'cross chassis.

Geoff Kabush (Maxxis-Rocky Mountain) is racing this season on a prototype carbon 'cross chassis. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) tilts his bars up high and runs his levers up even higher.

Geoff Kabush (Maxxis-Rocky Mountain) tilts his bars up high and runs his levers up even higher. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) had Crankbrothers' Eggbeater 11 pedals on his 'A' bike but as he only had one pair, his 'B' bike had last year's model installed.

Geoff Kabush (Maxxis-Rocky Mountain) had Crankbrothers' Eggbeater 11 pedals on his 'A' bike but as he only had one pair, his 'B' bike had last year's model installed. (Image credit: Jonny Irick)
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The Shimano Dura-Ace mechanical rear derailleur was bolted to a replaceable derailleur hanger.

The Shimano Dura-Ace mechanical rear derailleur was bolted to a replaceable derailleur hanger. (Image credit: Jonny Irick)
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Geoff Kabush's (Maxxis-Rocky Mountain) carbon tubular rims are anchored around Easton R4SL hubs.

Geoff Kabush's (Maxxis-Rocky Mountain) carbon tubular rims are anchored around Easton R4SL hubs. (Image credit: Jonny Irick)
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The internally routed rear brake cable helps keep it clean and also a cleaner surface for suitcase-style pick-ups.

The internally routed rear brake cable helps keep it clean and also a cleaner surface for suitcase-style pick-ups. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) doesn't mess around with carbon rails, sticking to fi'zi:k's k:ium option for his Antares saddle.

Geoff Kabush (Maxxis-Rocky Mountain) doesn't mess around with carbon rails, sticking to fi'zi:k's k:ium option for his Antares saddle. (Image credit: Jonny Irick)
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Geoff Kabush's (Maxxis-Rocky Mountain) team-only frame feature split seat stays.

Geoff Kabush's (Maxxis-Rocky Mountain) team-only frame feature split seat stays. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) races on custom Dugast tubulars covered in Maxxis treads. He uses the Raze for most days.

Geoff Kabush (Maxxis-Rocky Mountain) races on custom Dugast tubulars covered in Maxxis treads. He uses the Raze for most days. (Image credit: Jonny Irick)
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Muddier courses call for Geoff Kabush's (Maxxis-Rocky Mountain) custom Maxxis Mud Wrestler tubulars, built by Dugast on to the company's ultra-supple cotton casing.

Muddier courses call for Geoff Kabush's (Maxxis-Rocky Mountain) custom Maxxis Mud Wrestler tubulars, built by Dugast on to the company's ultra-supple cotton casing. (Image credit: Jonny Irick)
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The tapered front end should decrease fork shudder under hard braking.

The tapered front end should decrease fork shudder under hard braking. (Image credit: Jonny Irick)
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Geoff Kabush's (Maxxis-Rocky Mountain) team-only carbon 'cross bike uses a standard threaded bottom bracket shell.

Geoff Kabush's (Maxxis-Rocky Mountain) team-only carbon 'cross bike uses a standard threaded bottom bracket shell. (Image credit: Jonny Irick)
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TRP recently released a slightly wider-profile CR959 SL model to better match the power of Avid's Shorty Ultimate but Geoff Kabush (Maxxis-Rocky Mountain) sticks with the original CR950 model here.

TRP recently released a slightly wider-profile CR959 SL model to better match the power of Avid's Shorty Ultimate but Geoff Kabush (Maxxis-Rocky Mountain) sticks with the original CR950 model here. (Image credit: Jonny Irick)
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Shimano's nosed ferrule and rubber cap effectively seal off the most vulnerable piece of housing from water and dirt.

Shimano's nosed ferrule and rubber cap effectively seal off the most vulnerable piece of housing from water and dirt. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) used a 12-27T cassette for Saturday's Colorado Cross Classic.

Geoff Kabush (Maxxis-Rocky Mountain) used a 12-27T cassette for Saturday's Colorado Cross Classic. (Image credit: Jonny Irick)
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Shimano's 'cross-specific outer chainring doesn't boast the same ultra-stiff hollow construction as the standard road rings so profiled outer chainring bolts are used to maintain the sleek appearance.

Shimano's 'cross-specific outer chainring doesn't boast the same ultra-stiff hollow construction as the standard road rings so profiled outer chainring bolts are used to maintain the sleek appearance. (Image credit: Jonny Irick)
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Geoff Kabush (Maxxis-Rocky Mountain) uses an alloy stem but a carbon bar on his Rocky Mountain carbon fiber 'cross bike.

Geoff Kabush (Maxxis-Rocky Mountain) uses an alloy stem but a carbon bar on his Rocky Mountain carbon fiber 'cross bike. (Image credit: Jonny Irick)
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The 'cross season is still young but Geoff Kabush's (Maxxis-Rocky Mountain) Shimano Dura-Ace crank already bears the scars from some muddy races.

The 'cross season is still young but Geoff Kabush's (Maxxis-Rocky Mountain) Shimano Dura-Ace crank already bears the scars from some muddy races. (Image credit: Jonny Irick)
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Rocky Mountain includes a tapered carbon fork with Geoff Kabush's team-only carbon frame.

Rocky Mountain includes a tapered carbon fork with Geoff Kabush's team-only carbon frame. (Image credit: Jonny Irick)
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The top tube underside is just slightly flattened for shouldering.

The top tube underside is just slightly flattened for shouldering. (Image credit: Jonny Irick)

Geoff Kabush (Maxxis-Rocky Mountain) arrived at last Saturday and Sunday's UCI races in Boulder, Colorado with a new carbon fiber 'cross chassis currently unlisted in the Rocky Mountain catalog. According to team head mechanic Gary Wolff, Rocky Mountain supplied a few of these frames just for Kabush and might turn them into a production item but for now, they're team-issue only.

Kabush's frame features most of the features common to modern 'cross chassis these days: a tapered front end, internal cable routing, and what look to be carbon rear dropouts. We don't have a frame or fork weight available – and Wolff didn't know it – but total weight on Kabush's complete bike is a very competitive 7.55kg (16.64lb).

Easton adds even more carbon fiber to the mix with sub-1,200g EC90 SLX tubular wheels, the EC90 seatpost with molded carbon shaft and clamp, and the semi-anatomic EC90 SLX handlebar, and even TRP gets into the composite mix with its CR950 cantilevers.

TRP have released a slightly wider-profile CR959 SL cantilever to better match the power of Avid's Shorty Ultimate lever but Geoff Kabush sticks with the original CR950

Shimano provides a complete Dura-Ace drivetrain and mechanical transmission, including the shift/brake levers, both derailleurs, the chain, 12-27T cassette, and forged aluminum crankset with 'cross-specific 39/46T chainrings. As is common practice, Kabush runs the levers run up on the bars and despite his large-sized hands, the reach is brought in just a touch for easier braking and shifting while in the drops.

Kabush is sponsored by Maxxis but the company notably doesn't make 'cross tubulars and at this level of the sport, they're a virtual necessity to even think about being competitive. The team has gotten around the problem, however, by sending stock Maxxis clincher tires over to tubular tire expert Dugast, where the treads are carefully removed and them hand-glued on to a supple 32mm-wide cotton casing.

Kabush races on custom Dugast tubulars covered in Maxxis treads. He uses the Raze for most days

The end result is the tread that Kabush wants but also with the suppleness he needs. For most courses, Kabush says he runs the Maxxis Raze tread with its fast-rolling but reasonably openly spaced square knobs but he also has a set of custom Mud Wrestler tubulars for sloppier courses.

Rounding out the mix are fi'zi:k Antares k:ium saddle and padded tape, an FSA integrated headset, Crankbrothers' feathery Eggbeater 11 pedals, and Shimano cables, housing, and sealed end caps.

Kabush uses an alloy stem but a carbon bar on his Rocky Mountain carbon fiber 'cross bike

This article originally appeared on BikeRadar

Complete bike specifications

Frame: Rocky Mountain Solo Carbon prototype
Fork: Rocky Mountain Solo Carbon prototype
Headset: FSA Orbit integrated
Stem: Easton EA90, 120mm x 0°
Handlebars: Easton EC90 SLX3, 44cm (c-c)
Tape/grips: fi'zi:k dual:tape
Front brake: TRP CR950 w/Easton carbon-specific pads by SwissStop
Rear brake: TRP CR950 w/Easton carbon-specific pads by SwissStop
Brake levers: Shimano Dura-Ace STI Dual Control ST-7900
Front derailleur: Shimano Dura-Ace FD-7900
Rear derailleur: Shimano Dura-Ace RD-7900-SS
Shift levers: Shimano Dura-Ace STI Dual Control ST-7900
Cassette: Shimano Dura-Ace CS-7900, 12-27T
Chain: Shimano Dura-Ace CN-7900
Crankset: Shimano Dura-Ace FC-7900, 175mm, 39/46T
Bottom bracket: Shimano Dura-Ace BB-SM7900
Pedals: Crankbrothers Eggbeater 11
Wheelset: Easton EC90 SLX tubular
Front tire: Custom Maxxis Raze tread on Dugast tubular casing, 32mm
Rear tire: Custom Maxxis Raze tread on Dugast tubular casing, 32mm
Saddle: fi'zi:k Antares k:ium
Seat post: Easton EC90 Setback
Bottle cages: n/a
Computer: n/a
Other accessories: Shimano SP41 derailleur housing and sealed end caps

Critical measurements

Rider's height: 1.90m (6' 2")
Rider's weight: 75kg (165lb)
Saddle height, from BB (c-t): 775mm
Saddle setback: 75mm
Seat tube length, c-t: 585mm
Seat tube length, c-c: 540mm
Tip of saddle nose to C of bars (next to stem): 570mm
Saddle-to-bar drop (vertical): 50mm
Head tube length: 180mm
Top tube length: 570mm
Total bicycle weight: 7.55kg (16.64lb)