After racing the Trans-Provence in France and couple years ago, GT product manager Todd Seplavy noted some differences in the European mountain bike scene. In particular the XC crowd, who tackled big mountain riding on shorter travel bikes that were equally capable ascending as descending.

That got him thinking. Admittedly, the XC race market is shrinking, and the hardcore, calorie-counting set are mostly going to race hardtails anyway. But that doesn’t mean there aren’t a ton of people riding XC on a daily basis, and for that, the new Helion (pronounced ‘heel-eeon’ and not ‘hell-yun’) looks to imbue a capable trail bike with XC performance.

To get that blend of fun and raciness, they gave it a slightly slacker head angle, lower BB and longer top tube. And, of course, 27.5” wheels. Why 27.5″ wheels for a cross country bike? Lots of reasons…


Twenty nine inch wheels have come to dominate XC racing, but GT thinks in some cases the middle wheel size is better. Why? Because rolling speed is only part of the equation. They wanted something that was equal parts fun, able to accelerate quickly and have really good descending properties. It’s not just about being fast in a straight line, it’s a combination of reducing inertia and reducing braking time, increased agility and more geometry options (lower standover, shorter chainstays, tighter suspension package, etc.), particularly at the smaller frame size range. That means better fit for a wider range of rider heights. Oh, and it’s lighter.


They adapted their AOS (Angle Optimized Suspension) linkage design from the 2014 Force and Sensor to work in a shorter travel, 110mm setting. AOS works by isolating the drivetrain from the suspension, much like their original I-Drive for longer travel bikes. The difference here is it’s biased toward going up hill rather than downhill, making pedaling much more efficient. The PathLink, which is the main rocker, uses a new LOCKR expanding axle system that’s lighter and stiffer than before.


Like the other models, the Pathlink rocker is forged as two halves then welded together. That lets them shape the inside to reduce weight without the added time and expense of extensive machining.



The bikes come with remote controls for the rear shock since it sits so low on the frame. Most Fox equipped models get CTD versions with their newer, lower profile remote. Others spec different shocks with lockout only.


While the suspension focuses on keeping things fast and efficient, the geometry adds the fun. A size medium frame has a 69.5º head angle, 606mm ETT, 325mm BB height and 1090mm wheelbase. So, slacker than a typical XC bike, which lets you be a little more aggressive in the descents. The longer top tube helps keep the front wheel out in front on steeper drops, too.


They’re also stocked with nice, wide 740mm handlebars across the range.


Other features include full length housing with external runs for brakes, shifting and rear shock remotes. Given the shorter travel and design intentions, none of the models are spec’d with a dropper post.


Rear brakes get GT’s standard replaceable direct mounts so you don’t have to worry should you strip a threaded insert.

One notable spec choice comes on the Carbon Pro – it gets the e*thirteen oversized EX Cog on the cassette with a single front chainring to give the bike wider range on a Shimano-equipped drivetrain. We’re stoked to see some of these hop-up kits get used in an OEM spec!



The alloy models get all the same features of the carbon frames but in less expensive builds. The top model still sees a respectable build, and they trickle down to some very affordable options.


Even the tube shaping mimics the carbon versions pretty closely.



The top alloy models also share the carbon bikes’ 12×142 rear thru axle, but bottom two models switch to a standard quick release.


Full carbon models get carbon fiber front triangles and rear ends, alloy bikes are all alloy. Claimed weights are 2,241g for medium carbon frame (w/o shock) and 2,825g for medium alloy frame (w/o shock). Alloy bikes come in XS through XL, Carbon are Small thru XL. They come stock with 110mm travel forks, but you could run a 120mm fork, too. Spec highlights are:

Helion Carbon Team $7,499
– not available in US
– Fox 32 FACTORY Float/CTD suspension with Boost Valve rear shock & dual remote lockouts
– Stan’s Crest rims with DT 240 hubs
– XTR 1×11 full group

Helion Carbon Pro – $4,999
– Fox 32 Float/CTD suspension with Boost Valve rear shock & dual remote lockouts
– XT 1×10 drivetrain w/ e*thirteen oversized cog (US, S. America, Asia)
– XT 2×10 drivetrain (Europe)
– XT brakes

Helion Carbon Expert – $4,099
– Rochshox Reba RL w/ remote lockout
– Fox CTD BV shock w/ remote lockout
– Stan’s Rapid rims and sealed hubs
– XT/SLX drivetrain
– SLX brakes

Helion Alloy Pro – $3999
– not available in US
– Fox Float/CTD suspension with dual remote lockout
– XT drivetrain
– Maxle rear thru axle

Helion Alloy Expert – $3,199
– Fox 32 Float/CTD suspension with dual remote lockout
– XT/SLX mix
– Maxle rear thru axle

Helion Alloy Elite – $2,349
– Rockshox XC32
– X-Fusion shock
– WTB tubeless wheels
– Deore/SLX mix
– QR rear axle

Helion Alloy Comp – $1,549
– SR Suntour Raidon air fork w/ lockout
– X-fusion shock
– Alivio 3×9 drivetrain
– Shimano disc brakes
– QR rear axle

Frameset also available for European markets. Look for availability in late summer/early fall.


  1. Nice. Around where I live, most people don’t need either 130mm of travel or XC race geo, so this looks like a sweet option.

  2. GT’s old XC bikes (ala Zaskar 100 26″) had 69.5 degree head tube angles. The old Sensor did as well. And not Giant has gone that way with both the 27.5 Anthem and XTC. So yes this appears to be a departure from the normal XC race bike, but is it really anything new for GT. And is it possible they have been a bit ahead of trends in this area for a while? Or is that over simplification of things? Also, the last 26″ Zaskar and Sensor had the same HTAs but the Sensor had shorter chain stays, making it shorter overall. It seems to me this year’s Sensor is basically a combination up of last year’s Force’s geometry, 20mm less travel, 27.5″ wheels, and AOS. Which is a trend I saw Giant has and is doing (ie take 26″ from next longer travel segment, shorten the travel, give it 27.5″ wheels and gently tweak geo to taste). So is this bike a short travel 26″ Sensor with 27.5″ wheels and AOS, or a long travel Zaskar 100?


  3. When I read the title I though this could be just the bike I’d been looking for but for me it would need a dropper post with stealth routing, a short stem, a bit more tire clearance and I’d prefer 29 wheels. Maybe if they could make the XS-M in 650B and M-XL in 29er?

    I’d still love to demo one with a dropper post, ~60mm/70mm stem and a 120mm fork though.

  4. as long as there’s *some* available routing for a dropper post of the consumer’s choice, i’d just as soon it didn’t come with a crap stock one. i think this will be a smart choice for a lot of my customers, and maybe myself. looking forward to having one in the shop. GT is to be reckoned with in 2015 it looks like, and not just in DH. good news for me. (prodeal!)

  5. Looks so close to two water bottle mounts 🙁
    Specialized is killing it in that respect.
    Sacrifice a lil stand over height

  6. None of the trails being rode in the video necessitated nor showed off the suspension.

    Then again I’m a hardtail stalwart until my body says otherwise.

    But seriously, why all the ridiculous skidding in corners? That’s not how to ride.

  7. @Brad

    Have you looked at the Avanti Ridgeline 29 (presuming it’s available where you are)?

    100mm travel, reasonably slack 29er trail bike. I think they can run an internal dropper. A couple of people I know have them and love them, one with a 120mm fork up front to slacken it out a little more.

  8. I’d buy it if it was a 29er. It would be great for marathon racing. This looks like something for the European market.

    BTW You will see even 29ers going to head angels around 69.5° as well now that the chain stays are going down to 435mm and there abouts, the new Cannondale HT is an example.

  9. So all of a sudden 27’5″ is a good wheelsize for XC?
    Keep up with MTB trends is even more difficult than with computer stuff…

  10. The GT Helion makes sense if you live in the mountains. A truly good climber, and very capable descender.
    Good good GT for recognizing this niche.

  11. @gillis how can you say “thats not how to ride”?
    Of course you are entitled to your opinion but I think I speek for a large percentage of us when I say as soon as mtbing is no longer about or allowed to be riding in a way that is most fun I wont do it anymore.
    I really like that GT is bringing another new type of bike to the table. Definitely on my radar.

  12. What are they speaking about ?
    – reducing braking time ? IMHO this is better with the more GRIP of 29er wheels.
    – Short chainstay ?
    So Specialized Enduro 29er with 430mm stays or BMC trailfox with 435mm how is possible ?

  13. @gillis, I agree that the trails selected didn’t do much to show suspension at work. those were pretty groomed and I’d like to rip em on my ss. but, c’mon about the fun and skidding. It’s a marketing video. There’s like one superfluous skid to get some dirt flying while showing off a ‘dirt bike.’
    that said, and cool marketing video aside, i’m sticking to my hardtail for now. I did ride a nice full sus recently. It’s crazy how comfortable a ride in the woods can be – I just can’t bring that much change to my riding right now. I mean the ride was so good; so comfortable; so fast; I just can’t get my head around it. It wasn’t like ‘mountain biking’ has been for me for the last 25 years or so.

  14. Where i live and ride trail erosion is a problem and excessive and/or unecessary skidding is generally frowned upon.

  15. Where can we find complete geo numbers? What’s front-center and rear-center, for example? And SO height and BB height?

  16. I’m digging this style of bike. Just what I’ve been looking for. Although I don’t agree with GT’s assessment that it can’t be as “fun” if it were a 29er. I’m now wondering what this bike will be like with bigger wheels.
    Where can we get the complete geo numbers? I’d like to know the chainstay length for one. Also, the TT on the medium seems long.
    I find it funny that GT tout the AOS to be efficient and yet they go to the trouble of installing a remote for the CTD.

What do you think?