GT Helion Carbon Expert review

Burlier than the average cross-country rig

Our rating 
3.5 out of 5 star rating 3.5
GBP £3,000.00 RRP | AUD $4,499.00

Our review

An impressively capable frame, which outshines some of its components when pushed hard. Quite heavy though
Buy if, You want something a little chunkier than most xc bikes, and are willing to make a few tweaks to maximise its potential
Pros: Gutsy, lively ride, impressively stiff frame
Cons: Frame can take more punishment than some of the kit
Skip to view product specifications

The Helion is billed as an “aggressive cross-country bike” courtesy of some burlier spec choices and lower, slacker and longer than average (for XC) geometry. Sounds good, right? We hit the hills to see how it behaved.


At the Helion’s heart sits GT’s Independent Drivetrain Angle Optimised Suspension system with its high main pivot and meaty Path Link. This rocker arm compresses the shock, houses the BB – in theory helping to isolate pedalling forces – and connects the front and rear triangles.

Classy spec sheet

Fox’s latest DPS rear shock – albeit in cheaper Performance, not top-end Factory, guise – burrows its way through the split seat tube of the carbon front triangle. A bar-mounted remote lets you toggle through its three modes and control the 110mm (4.3in) of rear travel. Cables are routed externally, with things getting a little busy above the BB area.

GT’s floating bb ‘aos’ design is meant to isolate the suspension from pedalling forces: gt’s floating bb ‘aos’ design is meant to isolate the suspension from pedalling forces
GT’s floating BB ‘AOS’ design is meant to isolate the suspension from pedalling forcesOur medium frame had a 69.5-degree head angle, 606mm effective top tube and 440mm chainstays, and the BB stood 330mm off of the floor.Related: Which is faster: hardtail or full-suspension?

Everything on the Helion Carbon Expert is top-notch stuff – just as it should be at this price. GT has included Shimano’s latest 2×11 XT transmission complete with 11-42t cassette. At 13.3kg (29.4lb), you’ll be glad of the wide gear spread, especially if you have a lot of miles in your legs already.

With just 110mm of rear travel and a carbon mainframe you’d expect the Helion to be a touch lighter than 13.3kg. Fortunately, the impressively stiff frame and the bar-mounted remote that lets you lock out the rear suspension mean that the GT is more efficient than its weight would suggest when it comes to putting the power down through the pedals.

Singletrack slayer

With the shock’s low-speed compression damping in ‘open’ mode, the Helion will claw up the face of any technical climb, with plenty of rear wheel traction and without excessive suspension bob, even at slower speeds.

The helion lights up on technical singletrack: the helion lights up on technical singletrack

The Helion lights up on technical singletrack

Technical singletrack is where the GT really comes to life though. The wide bar and relatively short stem help make for lively, accurate steering, while the well balanced, supple suspension delivers predictable handling and more grip than expected from the low-profile tyres. Increase the speeds further and it becomes obvious just how capable the frame is.


The Helion’s rear suspension deals with the big hits impressively well, with just enough progression and control that you’ll throw it into far nastier situations than would normally be wise with this amount of travel. But it’s in these situations where the frame’s capabilities overshadow its components, which are more XC focused. Slap on a shorter stem, more aggressive front tyre and stiffer fork and the Helion would be a right ripper.

Product Specifications


Name Helion Carbon Expert
Brand GT

Available Sizes S M L XL
Saddle /WTB Silverado Race SL
Wheelbase (in) 42.91
Top Tube (in) 23.86
Standover Height (in) 35.52
Seat Tube (in) 18.11
Chainstays (in) 17.24
Bottom Bracket Height (in) 12.8
Weight (kg) 13.3
Stem Race Face Ride 35, 70mm
Shifters Shimano Deore XT
Seatpost Race Face Ride
Seat Angle 70.5
Rims WTB ST i23
Brakes Shimano SLX
Rear Tyre Maxxis Ikon 27.5x2.2in
Rear Shock Fox Float DPS Performance w/ three-position remote
Rear Hub Shimano SLX
Rear Derailleur Shimano Deore XT
Head Angle 69.5
Handlebar Race Face Ride 35, 740mm
Front Tyre Maxxis Ardent Race 27.5x2.2in
Front Hub Shimano SLX
Front Derailleur Shimano Deore XT
Frame Material Carbon fibre front triangle, 6069 aluminium rear triangle
Fork RockShox Reba RLT w/ remote lockout
Cranks RaceFace Aeffect SL, 36/26T, 2x10
Frame size tested M