These two premium full-face helmets optimise for opposite things. The AGV K6 S is the safety-data leader — the lightest full-face we cover, with genuine US DOT + ECE 22.06 and a perfect 5/5 SHARP score. The Arai Contour-X is the fit specialist — a DOT + Snell M2025 lid with the roundest interior in the class. The decision is really about whether data-and-weight or fit-and-comfort leads for you.
Certification and data: the K6 S leads
The K6 S carries genuine DOT + ECE 22.06 and a 5/5 SHARP score — the current rotational standard plus top independent impact data, on the US helmet. The Contour-X is US DOT + Snell M2025(its European Quantic twin is the 22.06, 4/5 SHARP unit). Both are superbly protective, but on the exact US helmets, the K6 S holds the current standard and the higher independent score. If certification data is your deciding factor, it's the clear pick.
Weight: the K6 S wins
The K6 S is around 1,255 gof carbon-aramid — one of the lightest full-face helmets made — versus the Contour-X's ~1,530 g. That's a real difference in neck fatigue over a long day and a lighter, more agile feel through corners. The Contour-X isn't heavy, but it can't match the K6 S's featherweight number.
Fit shape: the Contour-X wins
This is the Arai's whole reason to exist. The Contour-X has the roundest interior of any full-face we cover — a genuine relief for round-oval heads that the sportier, snugger K6 S will pinch. The K6 S suits intermediate-oval-to-sporty heads. If your head is round, the Contour-X may simply be the more comfortable helmet by a wide margin, and a helmet that fits is the one whose protection you actually get.
Character and features
Neither has a sun visor — both keep the shell clean and light. The K6 S is the sportier helmet, with a huge racing-derived field of view; the Contour-X is the all-day-comfort helmet with Arai's smooth glancing shell. Both are impeccably finished. So beyond data and weight vs fit, it's also a sporty-vs-relaxed character choice.
The verdict
Want the lightest helmet with the best safety data and a sporty fit? The AGV K6 S — the safety-data leader of the class. Have a round-oval head, or want Arai's all-day comfort and smooth-shell approach? The Arai Contour-X. Let head shape and priorities decide — see the K6 S review and Contour-X review, or the lightweight roundup.
How we picked
We compiled published specifications, cited each helmet's certification (DOT, ECE 22.06, Snell, SHARP) from the standards body or manufacturer homologation, and aggregated owner reports, then scored against a published method. The scores are judgments from documented research — not measurements we took. We do not run a crash lab. Certifications reflect the US-market build; where it differs from the European version, we say so and cite it.
