Change C17 is the darkest of the new Atom colourways and the most graphic: a matt navy shell with angular orange and red shapes cutting across the flank and over the crown, black chin bar, and the MT logo picked out on the side. What sits behind the paint is a chin bar mechanism worth understanding before you buy any modular helmet.

How the chin bar actually works

A single button under the chin releases the bar, which then rotates up and back over the crown. One gloved hand, one movement, and it stays where you put it.

The thing to check on any modular is not whether it opens but how it closes: the bar has to seat and latch in one push, with an audible click, without needing to be helped into place. A mechanism that requires two hands or a wiggle is one you will eventually ride with unlatched. On the Atom 2 SV the bar drops shut under its own weight and the latch engages at the bottom of the travel.

P, J, and the question MT does not answer

ECE 22.06 marks a modular helmet with a P if the chin bar is tested as protective and the helmet is approved to be ridden closed, a J if it is approved to be ridden open, or both. The marking is printed on the label sewn into the chin strap.

MT does not publish which marking the Atom 2 SV carries, and we will not infer one. The safe reading, and the one we recommend regardless of marking: ride it closed. A chin bar rotated back over the crown moves the helmet's mass and its aerodynamic profile in ways nothing was designed around, and a P-only helmet ridden open is riding in a helmet that has not been tested in that configuration at all.

If riding open matters to you specifically — some riders want it in slow city traffic in summer — read the strap label before you rely on it, on this or any modular.

About the Change C17 finish

Matt. The base is a deep navy with graphite panels; over it run angular orange and red shapes — long wedges along the flank, a broken chevron across the crown, and smaller fragments scattered towards the tail. The chin bar and the visor mechanism cover are black.

Navy is an underused base colour on helmets and a good one. It reads as dark without the flatness of black, it does not show dust the way grey does, and warm accents on it hold their saturation far better than the same accents on a black ground, where they tend to look muddy in overcast light.

ECE 22.06 and DOT

The Atom 2 SV clears the current European standard, mandatory since January 2024, and MT additionally lists DOT. The 22.06 uses 18 impact points against the 22.05's five, several impact speeds, an oblique impact against an abrasive anvil for rotational loading, and a Brain Injury Criterion ceiling.

What a mid-price modular gets you

MT developed the Atom 2 SV with the same team as the Thunder 4 SV, and the equipment list reflects that: a retractable MT-ESP sun visor aligned with the nose deflector, MT-FSOS visor opening with an automatic anti-fog position, an MT-ESLS release with a vent stop, a chin curtain as standard, a rear spoiler over a ventilation system developed with fluid-dynamics work, and translucent material in the vent pieces.

A Pinlock DKS512 insert is supplied in the box, which at this price is genuinely uncommon.

Weight: 1,700 g

The number is the honest cost of the mechanism, and it is about 200 g more than a comparable fixed full-face. There is no modular helmet anywhere that avoids this.

It matters least where a modular is most used — upright touring and commuting, where your spine carries the load nearly vertically — and most on a sports bike with your neck extended. Match the helmet to the posture and the number stops being an argument.

Retention

The strap closes on MT-MDTC, a micrometric ratchet with a double hook. The double engagement is the structural answer to the standing objection against ratchets — that a strap fastened on a single tooth can walk loose under vibration — while keeping the one-handed, gloved operation that makes a ratchet worth having on a helmet you open several times a day.

Ventilation, and where a modular loses out

Air enters at the chin bar and the brow and leaves under the rear spoiler; MT used fluid-dynamics work on the layout and gave the vent pieces a translucent material that is normally a high-end touch.

The honest limitation is structural rather than a design failure: a modular's chin bar has a hinge, a latch and a seal running through exactly the area a fixed full-face uses for a large chin intake. Every flip-up ventilates the face a little less well than a comparable full-face for that reason. The Atom's answer is the visor's anti-fog detent — a few millimetres of open screen does more for the inside of a visor than any chin vent, on any helmet.

Interior and repairability

The lining is fully removable and washable, and MT designs the external parts to detach individually so that a broken vent trim or a cracked visor mechanism cover is a spare part rather than a written-off helmet.

What it does not have

• No safety rating. The Atom 2 SV is not in the SHARP database, and no ADAC or Snell result exists.
• No published P/J marking — see above.
• No tinted screen supplied; the internal shade covers most situations.
• Matt paint cannot be polished. A scuff in the clearcoat stays.

In the box

• MT Atom 2 SV helmet — Change C17, matt navy with orange and red
• Protective bag, user manual and MT Helmets stickers
• Chin curtain fitted · Pinlock DKS512 insert supplied

Size guide

Specification

• Model — MT-Helmets Atom 2 SV · Part number — 1335E14C172 (XS–XXL: …03 to …08)
• Colour / finish — Change C17 — matt navy with orange and red graphics
• Homologation — ECE 22.06 and DOT · P/J marking not published
• Safety rating — none; not tested by SHARP
• Type — modular / flip-up
• Shell — HIRP (High Impact Resistant Polymer), approx. 1,700 g
• Sizes — XS to XXL
• Visor — MT-V-35 · MT-FSOS opening with anti-fog position · MT-ESLS release with vent stop
• Anti-fog — Pinlock DKS512 included · FogOff FOG013 compatible
• Sun visor — retractable MT-ESP, aligned with the nose deflector
• Chin bar — single-button release, latches under its own weight
• Retention — MT-MDTC double-hook micrometric closure
• Chin curtain — fitted as standard
• Interior — fully removable and washable, parts individually replaceable
• Communication — intercom-ready; no system supplied
• Manufacturer — MT Helmets, Spain
• Fitting — measure at the widest point above the brow; between sizes take the smaller
• Care — never wipe a dry shell; matt cannot be polished
• Replacement — after any impact, and after roughly five years regardless

• 1x MT Atom 2 SV helmet — Change C17 — matt navy with orange and red graphics
• 1x protective bag
• 1x user manual
• 1x sheet of MT Helmets stickers
• Chin curtain fitted as standard
• Pinlock DKS512 insert supplied