These two adventure flagships come at the category from opposite directions. The AGV AX9 is light, sporty and wide-view, with genuine US DOT + ECE 22.06; the Arai XD-5 is a round-fitting, hand-built DOT + Snell M2025Dtouring lid. The decision hinges on two things: which certification philosophy you want, and — just as much — which brand's head shape fits you.
Certification: AX9 carries current ECE 22.06 in the US
The AX9's US SKU is homologated DOT + ECE 22.06, the current rotational-test standard. The XD-5 is US DOT + Snell M2025D— a stiffer-shell standard for high-energy repeat impacts (its European Tour-X5 twin is the 22.06, 4/5 SHARP unit). If you specifically want the current 22.06 standard on the box you buy, the AX9 has it; if a Snell build suits your priorities, the XD-5 is a superb one. Neither is SHARP-tested in its US form, so there's no independent star score to break the tie.
Fit shape: the real divider
This is where they genuinely separate. The AX9 suits intermediate-oval heads and runs sporty and snug; round-oval riders often find it tight at the temples. The XD-5 is built round, and is the reference fit for round-oval heads. There is no "better" shape — only the one that matches your head — and this single factor decides more happy purchases here than any spec. If you know your shape, it may make the choice for you before certification even enters the picture.
Weight and field of view
The AX9 is the lighter helmet at around 1,510 gversus the XD-5's ~1,683 g, and its racing-derived eyeport gives one of the widest fields of view in adventure — a genuinely sporty, open feel. The XD-5 answers with Arai's all-day comfort and a peak that's a standout at speed. So the AX9 is the choice for a rider who wants light and sporty; the XD-5 for one who wants comfort and the round fit.
Character and the ride
The AX9 feels like the racing company's adventure helmet — sharp, airy, eager. The XD-5 feels like a hand-built touring lid that happens to have a peak — planted, comfortable, quiet for the class. Both convert for street and dirt, both have well-mannered peaks. Which character appeals is a real part of the decision, not a tiebreaker to dismiss.
The verdict
Intermediate-oval head, and you want light, sporty and genuine US ECE 22.06? The AGV AX9. Round-oval head, and Arai's fit and Snell build suit you? The Arai XD-5. Try to fit both if you can — head shape matters more than any spec here. Full detail in the AX9 review and XD-5 review.
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.
