Argon 18 Dark Matter review: this brilliant, well-priced all-rounder is one of 2026's best gravel bikes

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The new Dark Matter is Argon 18’s answer to what a gravel all-rounder should be. It's designed to be raced at the highest level, while offering class-leading tyre clearance and excellent handling to help it cope with more technical terrain.  

The Dark Matter is a very capable bike that feels swift on tarmac, but it really sings when it hits the dirt, with the excellent large-volume Schwalbe tyres crushing vibrations.  
 
Feeling so confident over a multitude of surfaces, the Dark Matter emerges as one of the star gravel bikes of 2026, earning it a place alongside exceptional all-rounders such as Mondraker’s Arid Carbon RR and the Parlee Taos. The latter took our coveted Gravel Bike of the Year gong last year.  

The bike I tested, with Rival XPLR AXS, retails at a competitive £4,500.

• Read more: Best gravel bikes in 2026 – top-rated carbon, aluminium, titanium and steel gravel bikes reviewed

Argon 18 Dark Matter frameset 

The Dark Matter carries lots of Argon 18’s design criteria. It uses the TCS (Topological Compliance System), where a frame is optimised in design and construction to bring optimal stiffness and compliance where each is most needed.  

In simple terms, anything below an imaginary line drawn from the top of the head tube down to the rear dropout is maximised for efficiency, and therefore stiffness. Everything above this line is optimised for compliance.  

The Dark Matter’s details hit all the right notes for a racy all-rounder – large 57mm tyre clearance, a future-proof SRAM UDH (Universal Derailleur Hanger) dropout, threaded T47 bottom bracket shell, plenty of mounts and integrated down-tube storage. 

Argon 18 Dark Matter geometry 

Compared to its predecessor, Argon 18 has slackened the new Dark Matter’s head tube angle by one degree to 71 degrees (size large). The brand has also steepened the seat angle to 73.1 degrees, and the front end is now corrected for a gravel suspension fork.  

My size-large test bike gets a sporty 603mm stack and a long 418mm reach. But Argon 18 utilises its ‘3D System’ (a series of flush-fit interlocking spacers at the head tube that stack underneath the upper bearing, maintaining head-tube stiffness no matter what stack height fits you).

You can opt for a more relaxed ride position by switching the spacers, pushing the stack up to 627mm and shortening the reach to 410mm.  

The standard lower and longer setting (603mm stack and 418mm reach) suited my favoured ride position perfectly. 

Argon 18 Dark Matter specification 

I opted for the SRAM Rival XPLR AXS model, which sits in the middle of the Dark Matter three-bike range.  

This combines SRAM’s latest Rival XPLR AXS groupset with DT Swiss G1800 alloy gravel wheels.

Other highlights include a nicely shaped FSA A-Wing Pro AGX gravel handlebar and comfortable Repente Quasar saddle, but the icing on the cake is the 50mm-wide Schwalbe G-One RX Pro tyres. 

A SRAM Force AXS and Zipp 303 XPLR S equipped model sits above the bike I tested at £6,500, and the £3,500 model below mixes Shimano GRX RX610 and RX822 groupset components.  

Since the spec is lower than both the 3T and Orbea I tested it alongside, the Dark Matter weighs in at 9.77kg – that’s a little over 500g heavier than the 3T Racemax2 Italia, and more than a kilo heavier than the Orbea Terra M21e Team. That said, the Argon 18 is the only bike on test to come with 50mm tyres.  

At £4,500, the Dark Matter represents good value – although Mondraker’s Arid Carbon R is cheaper at £4,199. Cervélo’s Áspero is £5,100 and Cannondale’s Topstone 1 AXS is £6,250. All of these bikes come with equivalent SRAM Rival XPLR AXS groupsets.  

Argon 18 Dark Matter ride impressions 

Despite being heavier with a lesser spec than its rivals, the Dark Matter isn’t a lesser performer in any way – in fact, it’s by far the superior all-rounder, whether that’s for recreational riding or gravel racing. 

The ride position is aggressive but not limiting, being more road-derived than some of its competitors from the likes of Mondraker, Marin and Whyte. 

Despite wearing 50mm tyres, the Dark Matter is no slouch on the road – it hums along on tarmac at a decent pace, even if it’s not as pacey as the 3T or Orbea.  

As soon as the surface underfoot gets rougher and tougher, the Dark Matter becomes a rapid, fast-handling, confidence-inspiring speedster that works with you as you lean, sprint, hop and corner over the most technical terrain. 

On one of my favourite singletrack descents, with chunky roots and wrist-battering horse-hooved ruts, the Dark Matter excelled, thanks to its direct yet stable-feeling frameset and stunningly good tyres.  

Speaking of tyres, the Schwalbe G-One RX Pros shone. My testing conditions combined very wet and muddy trails, sticky peaty soil, and rocky, rooty single and doubletrack, which would expose the limitations of many gravel tyres. 

While the G-One RX Pros' tight block tread can fill, they clear remarkably quickly, and they corner very confidently with lots of grip. They're almost the opposite of the skinnier and low-profile tread Schwalbe G-One RS Pros supplied on the 3T, which are prone to letting go in a corner without warning. 

Although the Rival XPLR AXS drivetrain is a rung below the Force XPLR AXS on the Orbea Terra, the difference is so minimal as to not matter – Force is just a little lighter.  

I couldn’t tell them apart on the trails – the shift speed and quality were identical, and the braking felt very similar. 

I wouldn’t decry anyone for wanting Force or Red above Rival XPLR, but I’d save money and go Rival every time if it were my bike – it’s a cheaper initial purchase and parts are less expensive to replace down the line. In any case, because there’s inter-compatibility between SRAM’s XPLR AXS 12- and 13-speed gravel components, you can upgrade parts later if you wish.  

The 460% range of the 10-46t cassette, combined with a 40t chainring, offers smooth progression and I had ample gears for descents and steep, technical climbs.  

The DT Swiss G1800 wheels are typically good quality from the brand – easy to live with, built to be robust, and with a modern 24mm-wide tubeless-ready hooked rim profile.

The only downside is they're not particularly light, at 864g for the front and 971g for the rear wheel. It’s testament to the Dark Matter’s great handling and ride quality that this doesn’t feel like an issue when riding, though.

Argon 18 Dark Matter bottom line 

The Dark Matter is a truly impressive all-rounder – quick enough for road and all-road adventures, while capable enough for the toughest terrain.

The frameset and brilliant tyres are the stars here, and despite it being comfortably the cheapest bike out of the trio I tested together, it more than holds its own.  

With its exciting and confidence-inspiring ride, and excellent versatility, the new Dark Matter is the epitome of what a modern gravel bike should be. 

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