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Pro bike: Aaron Gwin’s Specialized S-Works Demo 8

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This year the two-time world champ is racing aboard Specialized's flagship S-Works Demo 8

This year the two-time world champ is racing aboard Specialized's flagship S-Works Demo 8 (Image credit: Dan Severson/Future Publishing)
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Aaron Gwin took second at the first PRO GRT race of the season in Boulder City, Nevada

Aaron Gwin took second at the first PRO GRT race of the season in Boulder City, Nevada (Image credit: Dan Severson/Future Publishing)
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Specialized developed the Butcher with the help of Sam Hill and the Monster Energy/Specialized team

Specialized developed the Butcher with the help of Sam Hill and the Monster Energy/Specialized team (Image credit: Dan Severson/Future Publishing)
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Gwin was running Specialized's Butcher tires at Bootleg Canyon

Gwin was running Specialized's Butcher tires at Bootleg Canyon (Image credit: Dan Severson/Future Publishing)
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An X0 Type 2 short cage rear derailleur is tough enough for downhill racing

An X0 Type 2 short cage rear derailleur is tough enough for downhill racing (Image credit: Dan Severson/Future Publishing)
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There are two cogs missing from this 10-speed cassette. Note the plastic space/spoke protector

There are two cogs missing from this 10-speed cassette. Note the plastic space/spoke protector (Image credit: Dan Severson/Future Publishing)
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The S-Works Demo 8 has a carbon front triangle and an aluminum rear end

The S-Works Demo 8 has a carbon front triangle and an aluminum rear end (Image credit: Dan Severson/Future Publishing)
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A Fox RC4 rear shock keeps the rear end planted

A Fox RC4 rear shock keeps the rear end planted (Image credit: Dan Severson/Future Publishing)
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SDG I-Beam saddle and carbon seatpost

SDG I-Beam saddle and carbon seatpost (Image credit: Dan Severson/Future Publishing)
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Up front, Gwin is running CrankBrothers Mallet DH pedals, SRAM X0 cranks, a 36T Renthal SR4 chainring and e*thirteen LG1+ chainguide

Up front, Gwin is running CrankBrothers Mallet DH pedals, SRAM X0 cranks, a 36T Renthal SR4 chainring and e*thirteen LG1+ chainguide (Image credit: Dan Severson/Future Publishing)
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A Cane Creek 40-Series headset sits in the integrated head tube

A Cane Creek 40-Series headset sits in the integrated head tube (Image credit: Dan Severson/Future Publishing)
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SRAM's X0 group handles brake and shift duties

SRAM's X0 group handles brake and shift duties (Image credit: Dan Severson/Future Publishing)
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Gwin runs a 780mm-wide Renthal Fatbar handlebar

Gwin runs a 780mm-wide Renthal Fatbar handlebar (Image credit: Dan Severson/Future Publishing)
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A prototype version of the Fox 40 RAD. RAD stands for 'Racing Applications Development'

A prototype version of the Fox 40 RAD. RAD stands for 'Racing Applications Development' (Image credit: Dan Severson/Future Publishing)
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We're looking forward to seeing more of Gwin aboard the Demo 8 this season

We're looking forward to seeing more of Gwin aboard the Demo 8 this season (Image credit: Dan Severson/Future Publishing)

This article originally published on BikeRadar

BikeRadar has been profiling Aaron Gwin’s bikes since he first turned pro in 2008. The 25-year-old World Cup downhill racer first rode for Yeti aboard a 303 Factory DH, then for Trek on a Session 88 and 9.9.

Gwin has made some significant changes for the 2013 season, swapping Shimano for SRAM and leaving Trek for Specialized. We caught up with America's winningest male downhill racer in Boulder City, Nevada, following the first stop on USA Cycling Pro GRT.

New year, new team, new bike

Not surprisingly, Specialized’s top downhill racer is riding the company’s recently introduced flagship gravity bike, the S-Works Demo 8. New for 2013, it features a carbon front triangle mated to an aluminum rear end.

According to Specialized’s Sam Benedict, a carbon rear end is doable but the gains would be minimal and the price increase significant. “The gains you make in weight and stiffness are nowhere near that of the front triangle – we saved 500g on the front end alone,” he said of using carbon over aluminum.

The bike has short, 421mm chainstays and a low bottom bracket. An eccentric cam in the rear shock mount allows the rider to adjust the bottom bracket height from a low unsagged height of 338mm up to 353mm. The frame’s 1.5in head tube allows for AngleSet compatibility, should riders want to go slacker than the stock 64-degree head angle.

Like the rest of the Demo 8 line, the S-Works frame features a low slung, centrally mounted rear shock to keep the center of gravity low. The frame has 200mm of rear suspension travel via Specialized’s Horst Link.

The suspension arrangement looks more complicated than on the company’s other full suspension bikes. That’s due to the fact that the two pairs of 'seat stays' in the linkage have two very different roles: the upper stays and link control the axle path, while the lower stays drive the shock, controlling the spring rate. In addition to bolstering rear end stiffness, this setup allows Specialized’s engineers to tune spring rate and axle path independently of one another.

SRAM X0 – capable of more than XC and trail riding

In addition to switching bike brands, Gwin has swapped Shimano for SRAM. His bike was kitted out in full SRAM X0 in Nevada, with Renthal supplying the 36-tooth chainring and e*thireen’s LG1+ providing chain retention.

Gwin has also opted to run the lighter and still quite powerful X0 Trail brakes, rather than Avid’s downhill-specific Codes. The X0 Trail can be thought of as a scaled-down version of the Code; the four-piston calipers provide ample stopping power in a much lighter package.

Gwin still suspended by Fox

What hasn’t changed is Gwin’s suspension partner, Fox Racing Shox. Up front there’s what appears to be a prototype Fox 40 RAD (Racing Applications Development). We first spotted the air-sprung Fox 40 suspension forks last spring, at the first World Cup stop in Pietermaritzburg, South Africa.

The updated Fox 40 features a lighter chassis that, in conjunction with redesigned internals with a positive air cartridge, is said to be approximately a pound lighter than the 3.14kg (6.93lb) Fox 40 FIT RC2 fork.

At the rear it appears Gwin is running Fox’s RC4 coil shock.

The Demo family has evolved from a freeride platform to a collection of purebred World Cup race machines. We're interested to see how Gwin's input shapes the future of the range, as well as how his setup evolves throughout the 2013 season.

Complete bike specification

Frame: Specialized S-Works Demo 8
Shock: Fox DHX RC4
Fork: Fox 40 RAD
Headset: Cane Creek Forty Series, integrated
Stem: Renthal Integra, 50mm
Handlebar: Renthal Fatbar, 780mm
Tape/grips: ODI Ruffian
Front brake: Avid X0 Trail, 200mm HS1 rotor
Rear brake: Avid X0 Trail, 200mm HS1 rotor
Rear derailleur: SRAM X0 Type 2, short cage
Shift levers: SRAM X0
Cassette: SRAM PC1070 chopped to 8-speed
Chain: SRAM 1091R
Crankset: SRAM X0 DH
Bottom bracket: SRAM PF30 DH, 83mm shell
Pedals: CrankBrothers Mallet DH
Rims: DT Swiss FR 600, 36-hole
Front hub: DT Swiss 240s, 110x20mm
Rear hub: DT Swiss 240s, 150x12mm
Tires: Specialized Butcher DH 26x2.5in
Saddle: SDG I-Fly
Seatpost: SDG I-Beam Micro Carbon

Critical measurements

Rider's height: 1.78m (5ft 10in)
Rider's weight: 74.8kg (165lb)
Seat tube length, c-t: 419mm
Head tube length: 112mm
Top tube length: 580mm
Head angle: 64 degrees
Seat tube angle (effective): 76 degrees
Wheelbase: 1,191mm
Chainstay length: 421mm

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