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EB16: AX Lightness teases VIAL evo Gravel prototype, plus news on the XC, road, wheels & saddles…

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Just a few weeks before Eurobike we got a sneak peek at the new lightweight cross country racer from AX Lightness – the Vial Evo XC hardtail with its 870g frame.  Now the superlight carbon craftsmen at AX have finally let more details loose on a bike that we’ve know they were developing for sometime. The new Vial Evo Gravel aims to blend the trail performance of the XC with the speed and weight savings of their Ultra road bike. Coming in between but able to tackle any terrain, AX has set their goal of building the first complete production gravel bike under the 6.8kg UCI, and it seems they have hot that mark, even with up to 2.1″ tires. Take a closer look after the break as we get up close and personal with the new bike. At the same time we get another focused look at the XC bike, and how AX has simplified their frame and wheel lineups, and revamped a couple of crazy light saddles for more comfort…

VIAL evo Gravel

ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_toptube ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_3t-luteus-ii-fork

First, what we do know about the new Vial Evo Gravel is that it won’t be available until at earliest the beginning of 2017. The bike we see here was called a prototype, but looking closely, it is pretty clearly well finished and close to production. Our guess is that AX is done will their design and just working out finalizing the molds and and carbon ply layups across their full size range.

The bike is a mix between the 700c road Vial and the 29er cross country Vial, so comes in between for tire sizes. That means that it is designed to fit up to a 700 x 40mm gravel tire or a 27.5 x 2.1″ trail tire. In either guise AX has plenty of lightweight wheel options to keep the complete bike light. We were told that this bike as it stood weighed just 6.7kg (14.8lb).

ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_headtube ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_modular-routing

The headtube of the gravel bike gets its looks derived from the road-going Vial Evo, but with a slightly more prominent looking taper. The Gravel is matched to a 3T Luteus II LTD fork, which as we’ve seen already has the matching big tire gravel clearance with their Exploro frame, but uses a 15mm thru-axle.

The decision to stick with a single ring drivetrain means that the Vial Evo Gravel gets a clean cable routing setup. Both shift and brake lines share a single non-driveside cable port that uses a modular locking housing clamp to keep them from moving around or rattling inside the frame.

ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_1x-drivetrain ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_bottom-bracket

That 6.7kg total weight is more impressive when we look at the drivetrain on this bike. While many of AX’s show bikes hit superlight targets through the use of boutique (read: expensive) carbon components and maybe even durability compromises throughout, this one uses a mostly stock SRAM Force1 groupset. OK, so those Ashima ai2 rotors shave some weight off, and who’s to say how they help braking. AX’s own cockpit components certainly won’t keep the price tag low, but they are said to be able to stand up to solid off-road riding abuse. But in the end this 1x specific gravel bike should be able to be built up with a fairly reasonable set of components and still roll away really light.

ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_thru-axle-rear-routing ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_seatstay-bridge

The bike will use a 12mm rear thru-axle, of course with the same 142mm rear spacing of their XC bike. The seatstays on this bike are much thinner than the mountain bike suggesting a more compliant rear end for more time in the saddle. They also come together in a wide and flat seatstay bridge with a curious ridge in it the seems designed to control where the flex occurs (and away from the seat cluster.)

The seat cluster also makes a great example to see how AX Lightness puts together a frame. Building individual assemblies of different parts of the bike, like individual tubes or stay assemblies, they then overwrap the joints by hand, often with a different type of carbon depending on stresses, as they finally are put into the mold to become one.

ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_bottom-bracket-shaping ax-lightness_vial-evo-gravel_ultralight-carbon-275-gravel-road-bike_asymmetric-chainstays

Sticking with the 1x specific build the Vial Evo Gravel is able to keep its very asymmetric chainstays short and widely spaced to fit that fat rubber. It also leads to a bottom bracket cluster that provides a very broad connection for the wide downtube and seattube. That wide seattube, flattened front-to-back also suggests a focus on controlled flex and comfort at the saddle which meshes with the ever so slightly curve molded into the seatstays.

Brake mounts on this prototype were post mount and 160mm rotor only, but AX didn’t have any answer as to whether those would carry over into the production bike.


Overall frame weight is still a bit up in the air. Early claims set it at under 1000g. While that sounds fairly light for the rough and tumble life of a gravel bike that will encounter everything from smooth dirt roads to a fair share of technical trail riding, it’s a bit underwhelming for a bike from AX. (Remember that hardtail in the next image has an 870g frame.) The most recent notes we’ve heard from AX Lightness places frame weight for the new Vial Evo Gravel between 800-900g. That sounds more reasonable, and we can safely bet that they are working to get it to the lighter side of that range before it goes on sale to the public at the start of 2017.



We already got some details on the 3000€ Vial Evo XC frame, that had been more than 2 years in the making. The frame gets a long & slack modern geometry which should be a big help for stability on a bike that can be built up under 7kg/15.5lb. Anyone who has spent time riding a bike that light off road will have experienced it literally bouncing around on the trail just because of how light it is. The bike’s short headtube should allow for a low enough position, even for the most flexible racers over the 100mm 29er fork.

The rear end os the bike is a noticeable departure from the other framse AX has developed. Like the Gravel which was partly developed out of lessons learned on this bike, the XC gtes asymmetric chainstays. Here the difference is less dramatic at first glance, but the driveside stay is much taller and thinner to get the best balance of power transfer and chainring/tire clearance. Both chain and seatstays also use thicker sections towards the front end of the bike, tapering to very thin profiles as they approach the drop out to allow for more flex. AX sees this as not just adding comfort to the rider, but for a more important performance benefit to let the rear wheel move a bit to better track the ground and provide improved traction without bouncing, again a big deal for an ultralight trail bike.

ax-lightness_vial-evo-xc_ultralight-carbon-29er-hardtail-mountain-bike_bottom-bracket ax-lightness_vial-evo-xc_ultralight-carbon-29er-hardtail-mountain-bike_rear-thru-axle-post-mount-brake

The bike builds on the success of years of developing ever lighter Vial Evo road bikes. And to hit the design target of 427mm chainstays they spread the stays as far as they could and even curved the seattube on the 29er. Like the Gravel bike, the XC is also 1x specific, making no accommodation for a front derailleur.

At the back the bike uses a light X-12 thru-axle as part of an all-new for AX dropout assembly. The bike sticks with 142mm rear spacing. It uses a captured nut post mount brake setup inside of the rear triangle with clean internal routing through the top of the chainstay.

VIAL evo Ultra & Race


On the road side of things, updates are pretty minor. The Vial Evo line up goes mostly unchanged for 2017, save for a much appreciated boost in tire clearance. With the explosion in popularity of wider tires, that might be seen as the reason for the update, but it is in fact the expansion in with of lightweight wheels. The move from 15mm internal rims to somewhere around 20mm becoming the new norm, riders on lightweight road bikes have been having clearance issues even when mounting 23 or 25mm tires. All of the new Vial Evos will now clear a tire up to 28mm wide (real measurement). That doesn’t mean many riders will try to mount a 28 on a 4.4kg road bike, but now they should be safe with 25s on most wheels.


The other big move on the road since AX Lightness was helped out of financial troubles by the buyout last fall from Benobikes, is that the Vial Evo line has been simplified (as have the wheels.) AX Lightness has kept all of the design, development, and production team (they are actually back in expanding mode again now), but now when they develop new and better tech, they will phase out the lower-end stuff more quickly.

That means the top-level, lightest will remain with the Ultra designation, as the eTap Vial Evo Ultra with red AX decals above. Then the only other level of the road frame will be the Race which gets a slightly heavier, more durable frame and also raises the max rider weight limit. This Vial Evo Race bike is said to offer slightly more aggressive geometry and will be sold both directly under the AX brand, as well as under now sister brand Benotti as its premier made-in-Germany road bike.

ax-lightness_vial-evo-ultra_ultralight-carbon-road-race-bike_wireless-specific ax-lightness_vial-evo-ultra_ultralight-carbon-road-race-bike_customizable-routing

On the Vial Evo Ultra side, AX has also added the option for more customization. As more and more wireless and semi-wireless drivetrain options join the likes of Di2 & EPS, most manufacturers have added modular cable routing solutions. AX Lightness can do that, but they are also happy to build your bike with fewer cable ports for a cleaner (and marginally lighter) look to your premium bike.

UD rims

ax-lightness_light-carbon-rims_ud-unidirectional-carbon-finish-option ax-lightness_light-carbon-rims_3k-weaveud-carbon-finish-options

AX wheel lineups have been simplified as well. Gone are several different levels of light rims built into complete wheels. Now all wheels that they sell to customers will use their top-end, lightest Ultra rims. Their second-tier (but still really light) Selection rims will now go only into wheels being sold to bike companies for OEM spec. That means simpler management from AX’s side, which should result in faster turnaround to customers, and maybe even a small reduction in pricing down the road?

All rims now will also be made available with a unidirectional (UD) outer carbon layer. The 3K weave versions will still be available, but to allow  buyers to better match other components, AX refined their layups a bit so they can deliver the same weigh, stiffness, and durability whether the outermost carbon ply is 3K or UD.

Leaf II & Endurance saddles


Lastly for saddles, AX has introduced a new version of their best selling saddle, now the Leaf II. The comfortable all carbon, unpadded saddle gets a new flush leather insert for a less slippery perch. They’ve also added a couple of new embossed leather finishes with either more texture or a 3K weave look.

ax-lightness_leaf-ii_ultralight-full-carbon-saddles ax-lightness_leaf-ii-plus_ultralight-full-carbon-saddle_new-textures

On top of the new Leaf, the same covers make their way to the Endurance. Both also get a full leather cover option as well.


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7 years ago

So nice!

Paul Wirz
Paul Wirz
7 years ago

Looks as they have copied the open up and one+

7 years ago
Reply to  Paul Wirz

Well, they did actually build the first generations of the Open bikes…

Gerard Vroomen
7 years ago
Reply to  Carlos

No they actually didn’t. We wanted them to build a new OPEN frame but two years and an enormous investment on our part later, the final frame they said passed all testing broke within a few hours of riding.

They did however still have a set of OPEN U.P. molds lying around …

7 years ago
Reply to  Gerard Vroomen

Wow, that’s rather unexpected seeing you here participating (frankly, I don’t go to comment section very often). Is there anywhere I can find what is the actual difference between Open UP and Exploro, as in why would I buy one over the other?

Sorry for question to a different topic, I just can’t talk to my LBS about this anymore.

7 years ago

The same bike available from x3 different brands. Hats off to Gerard Vroomen!

Gerard Vroomen
7 years ago
Reply to  Woody

Actually, the U.P. is only available from one brand: OPEN. Maybe you are referring to the 3T Exploro, but that’s a completely different design. But yes, also by me. As for this thing, well, what shall I say, see above.

7 years ago

What is the smallest chainring you can put on these gravel bikes?

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