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GT Helion Carbon Expert Complete Mountain Bike - 2015

Sale $2,418.99 $4,099.99 41% off

Item # GTE0006

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Item # GTE0006


It's hard to find a weak spot in the 2015 GT Helion Expert Carbon Complete Mountain Bike's armor. It's got top-notch materials, a revolutionary suspension platform, a great build, and for everything you get, we think the price ain't all that bad, either.

The Helion Expert's frame benefits from GT's recent years of investing enormously in developing the most advanced applications of carbon fiber to the world of mountain biking. While they have a few different versions of the specific carbon types they've developed, the Helion Expert utilizes only the lightest and strongest, called FOC Ultra. FOC stands for Force Optimized Construction, which is a vague way of describing GT's complicated proprietary process of allocating carbon to various areas of the frame and aligning its fibers within fractions of millimeters of precision to achieve maximum stiffness where the frame needs it, and shed all excessive weight at the same time. The result is a chassis that has only been on the market for a few months, but has already won numerous awards for its outstanding overall performance, and it's causing a lot of frustration among GT's competitors.

Helping out that performance is GT's revolutionary Independent Drivetrain suspension platform. The idea of isolating the drivetrain so that it's not affected by suspension movement is nothing new, but GT's approach is, and it works really, really well. The crankset and the rest of the drivetrain make their home entirely on the rear triangle, unlike many designs that put the crank on the mainframe and the rest of the drivetrain parts on the rear triangle. The problem with this is suspension compression that occurs with pedal force, robbing you of efficiency. It's simpler to build bikes this way — indeed, the I.D. system on the Helion is complicated to look at, but it works. Sprinting or out-of-saddle climbing is rewarded with hardtail-like efficiency, not dependent on a shock's damping, yet it's incredibly compliant, and the front half of the bike remains extremely stable. One spin and you'll see why we love it.

Tech Specs

Frame Material:
FOC Ultra Carbon
Rear Shock:
FOX Racing Shox FLOAT CTD Remote BV, 6.5"x1.5" Air Shock, w/ Rebound Adjust & Remote Lockout
Rear Travel:
110 mm
RockShox Reba RL 27.5 Solo Air
Front Travel:
110 mm
Orbit C-40-ACB
Shimano SLX, SL-M670, Rapid Fire
Front Derailleur:
Shimano SLX, FD-M676-D
Rear Derailleur:
Shimano Deore XT Shadow Plus, Direct Mount, RD-M786-D, GS Cage
Shimano SLX, FC-M675, 38/24T, 2x10
Bottom Bracket:
Shimano CS-HG81-10, 10-Speed, 11-36T
180 mm Shimano SLX, BL-M675
Race Face Ride
Handlebar Width:
740 mm
GT Statement Single Lock-on Grips
Race Face Ride
Stem Length:
80 mm
fizik Tundra2, Manganese Rail
Race Face Ride, 31.6x375mm
Seat Collar:
All Terra Alloy, 34.9mm
Shimano HB-M678, SLX, for Center Lock Disc Rotor, 32H, for 15mm thru type axle, Shimano Freehub, FH-M678, SLX, for Center Lock Disc, 8/9/10-Speed, 32H, for 12mm thru type axle
Continental X-King
Tire Size:
27.5 in x 2.2 in
Recommended Use:
cross country
Manufacturer Warranty:
lifetime on frame

sizing chart

Helion size by rider height


Geometry chart


Geometry Chart


Helion Carbon Team/Pro/Expert
110mm Travel Fork

Seat Tube


Effective Top Tube


Fork Offset


Stand Over

Head Tube


Head Tube Angle


Seat Tube Angle


Bottom Bracket Drop




S 18.1in 22.8in 1.6in 32.4in 3.5in 69.5o 70.5o 1in 17.2in 41.8in
M 18.1in 23.8in 1.6in 32.5in 4in 69.5o 70.5o 1in 17.2in 43in
L 19.3in 25in 1.6in 33.4in 4.7in 69.5o 70.5o 1in 17.2in 44in
XL 20.5in 26.1in 1.6in 34.4in 5.3in 69.5o 70.5o 1in 17.2in 45.2in

Reviews & Community


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Excellent bike, old school feel

  • Familiarity: I've used it several times

I long for the days of my 26" Bontrager OR hardtail. That bike was fun no matter what you threw at it. XC geometiries just feel good to me and the Helion made me feel like I was 20 years old again, railing that steel bike of old. Handling is quick. Suspension is more than sufficient for singletrack duty. The bike is on the heavy side and with both suspension lockouts, there's a spaghetti bowl of cables of front. Those two knocks are the reasons for 4 stars. But at this price point, it's a tough bike to beat.

Give me a shout if you want to know more...btowery@backcountry.com