Argon 18's new Anti Matter is a 1x-only aero gravel racer with 55mm clearance

Argon 18 has launched the Anti Matter, an aero gravel race bike that sits above the brand's adventure-focused Dark Matter and shares its platform DNA with the Nitrogen Pro aero road bike. The frameset weighs a claimed 1,050g in a medium — about 125g over the Nitrogen Pro — and Argon 18 claims a 14.5-watt aerodynamic advantage over the Dark Matter at 45 km/h. The full Red XPLR AXS build hits a claimed 8.1kg.

The bike is a direct response to how fast gravel racing has become. Product director Alexandre Côté told Cyclist that race speeds in major European and North American series have climbed by more than 30% since the late 2000s, and that the Dark Matter, Grey Matter, and Krypton no longer meet the requirements at the front of those events. The Anti Matter is meant to be the no-compromise race bike — pro-level road efficiency, optimised for dirt — and was first spotted at the Traka.Cyclist

Aero work was extensive: 800-plus hours of CFD simulation and 45 hours of wind-tunnel testing across 130 tube profiles. The cockpit is the same ATTEN CHB-01 one-piece bar from the Nitrogen Pro, claimed to save 6.7 watts at 45 km/h over a competing two-piece system. Argon 18 says it went 'as narrow as possible within the UCI regulations' in anticipation of the governing body's incoming handlebar width rules — bars are offered in 360mm and 380mm widths, with stems from 80mm to 130mm. Even the bottle cages get the aero treatment: the down tube cage is side-loading and sits flush against a shaped down tube so it can be reached when an ATTEN x Apidura frame bag is fitted.CyclistBikeRadar News

Geometry borrows directly from the Nitrogen Pro: 555mm stack and 392mm reach, which puts the Anti Matter 27mm lower and 14mm shorter than the Dark Matter. Chainstays come in at 425mm — 9mm shorter than the Dark Matter — with the seat tube offset relative to the bottom bracket to clear large tyres. Maximum tyre clearance is 55mm, with stock 45mm Schwalbe G-One RS Pro rubber. Côté said the 55mm number was 'a very conscious choice' to find the sweetspot where the front end stays stiff without the weight penalty of reinforcing for a wider fork. The frame uses a T47 threaded bottom bracket, UDH dropout, CeramicSpeed SLT headset and a standard 1-1/8in round steerer — the last point notable because it leaves the door open for a gravel suspension fork.CyclistBikeRadar News

Two design choices will be contentious. The Anti Matter is 1x-only — there is no front derailleur mount on the frame, and Argon 18 expects more performance gravel platforms to drop 2x in the next few generations. The cockpit is also wireless-only: at 360–380mm, the bars are too narrow internally to route mechanical or wired electronic shifting. Argon 18 frames both as deliberate calls for performance and packaging gains, but they meaningfully constrain the buyer pool.Cyclist

Three builds, all SRAM XPLR AXS. The flagship Red XPLR AXS gets Zipp 303 XPLR SW wheels, a power-meter crankset, the Schwalbe G-One RS Pro 45s and the ATTEN x Apidura frame bag for £10,495 / $12,999 / €12,495. The Force XPLR AXS step keeps the power meter and bag, swaps to Zipp 303 XPLR S wheels, and runs £7,495 / $8,999 / €8,995. The entry Rival XPLR AXS drops to DT Swiss G1800 alloy wheels at £5,495 / $6,499 / €6,795. A frameset is offered separately at £4,395 / €4,995.BikeRadar NewsCyclist