Read this first: the LS2 IRID Dynamic Dark visor supplied with this helmet is not road legal. LS2 sells it for track use, and its darkened state is below the light transmission any road-approved visor has to reach. The helmet itself is fully approved to ECE 22.06 and comes with a legal screen — but the visor this article number exists for belongs on a circuit, in daylight, and nowhere else.

Why a visor can be illegal when the helmet is not

Helmets and visors are approved separately, and the visor rule is about light rather than impact. A visor has to transmit at least 80 per cent of the light reaching it to be approved for use at any hour of the day or night. Between 50 and 80 per cent it can still be approved, but it is marked for daytime use only. Below 50 per cent it is not a road visor at all, and that is where a genuine dark track screen sits.

The Dynamic Dark is photochromic, so it has two states rather than one, and its dark state is the reason LS2 restricts it. That restriction does not soften because the sun is out or because the helmet underneath is approved.

In practice this matters in two places. A police check reads the marking on the visor, not the helmet. And your insurer, in the event of a claim, may read it as well. Neither conversation is worth the convenience.

Then who is this article for

Somebody who rides on circuits and wants one screen instead of a bag of them. On a track day the light changes constantly — pit lane, shadowed braking zones, a low sun on the back straight — and a photochromic that follows it is genuinely better than swapping a fixed dark visor twice a day.

You still need a legal screen for the ride there. LS2 packs a tinted visor with every GP Aero, and the helmet arrives with a screen fitted; the Dynamic Dark is the one that goes on when you sign on.

What LS2 claims for the visor, and what we would qualify

Twenty grams. Waterproof. No batteries, because the tint is chemical rather than electronic. An integrated anti-fog coating that LS2 tested to 120 seconds. A transition quoted at 0.09 seconds.

The 0.09 seconds is the figure we would treat with most caution — photochromic chemistry usually takes seconds to darken and longer to clear, and we have not tested this one. The temperature dependence is not a claim but a property: cold makes the dark state darker and the clearing slower, which on an autumn track day is a real effect rather than a footnote.

Two visors, one helmet: the swap itself

An article like this only works if changing the screen is quick, so it is worth describing what the mechanism actually asks of you. The GP Aero uses a tool-free quick release: the visor comes off its pivots without a screwdriver and without removing a side plate, which is the arrangement race helmets use because a pit-lane visor change happens under time pressure and often in gloves.

Two practical notes. Do the swap on a bench rather than on your knee, because a dropped visor lands on its coated face and a scratch across your line of sight is the one blemish you will notice every ride. And carry the screen you take off in the bag it came in rather than loose in a rucksack, for the same reason.

Matt carbon, and why it stays matt

A matt clear coat over a visible 6K carbon weave. It shows no highlights, hides fingerprints and photographs flat.

What it cannot do is recover. Polishing compound works by levelling a clear coat, which is exactly what puts the gloss back into gloss — apply it to matt and you get a shiny patch that never blends. Wash it wet, never dry, and accept that a scuff from a dropped helmet is permanent.

The shell

100 per cent carbon fibre, 6K weave, one outer shell size for XS to XXL, 1,280 g declared with a 50 g tolerance. Approved to ECE 22.06; the FIM homologation in this family belongs to the Thunder GP PRO, which is a different laminate on three shells.

The single shell size is the honest weak point. Padding, not shell size, makes the difference between XS and XXL, so the helmet suits the middle of the range best and both ends deserve a fitting.

Ventilation on a hot lap

Chin, brow and crown intakes feed channels cut into the EPS; the air leaves under the rear spoiler. A breath deflector keeps exhaled air away from the screen, which matters more with a dark visor than a clear one because fog is harder to spot before it bites.

The vents are operable in gloves. That is not a small thing when you are trying to open a chin vent on the warm-up lap.

The pads come out under load

The cheek pads sit on LS2's Emergency Release System: red tabs at the base pull them clear of the shell so a marshal can remove the helmet without rotating the rider's neck. On a helmet sold for circuit use, this is the specification that most deserves its place in the list.

ECE 22.06 — the helmet, not the visor

Eighteen impact points instead of five, several test speeds, an oblique impact against an abrasive anvil that measures rotational acceleration, and a Brain Injury Criterion assessment rather than peak deceleration alone. Vents and visor mechanism are tested fitted. Mandatory in the EU since January 2024. None of that changes the visor rule above.

What this helmet does not have

• No road-legal Dynamic visor. The dark version is for daylight track use.
• No FIM homologation. That is the GP PRO's.
• No sun visor, and none needed with a photochromic screen.
• One outer shell size across the six helmet sizes.
• No SHARP, ADAC or Snell result for any FF805 Thunder.
• No published noise figure, and we do not estimate them.

In the box

• LS2 FF805 Thunder GP Aero helmet — Matt Carbon
• LS2 IRID Dynamic Dark photochromic visor — daylight track use only
• Carrying backpack
• Tinted visor
• Pinlock Max Vision 120XLT anti-fog lens
• Tear-off films
• Reflective stickers

LS2 publishes a single packing list for the GP Aero model and none specific to the Dynamic versions. The list above is that packing list plus the visor this article number is built around.

Size guide

Size	Head circumference
XS	53–54 cm
S	55–56 cm
M	57–58 cm
L	59–60 cm
XL	61–62 cm
XXL	63–64 cm

Specification

• Model — LS2 FF805 Thunder GP Aero
• Part number — 168058814
• Finish — Matt Carbon
• Supplied visor — LS2 IRID Dynamic Dark, photochromic — track use only, not road legal
• Road use — fit the supplied clear or tinted screen; the Dynamic Dark is for daylight track use
• Homologation — ECE 22.06 (helmet)
• Shell — Carbon 6K, one outer shell size
• Weight — 1,280 g ± 50 g declared; the visor adds 20 g
• Retention — double D-ring, Emergency Release System pads
• Sizes — XS to XXL (53–64 cm)
• Photochromic behaviour — darkens and clears in 0.09 s, mechanical, battery-free
• Anti-fog — integrated coating tested at 120 seconds, plus a Pinlock 120XLT MaxVision lens
• Ventilation — three intakes, channelled EPS, exhaust under the spoiler
• Interior — removable and washable, hypoallergenic laser-cut foam

• 1x LS2 FF805 Thunder GP Aero helmet — Matt Carbon + IRID Dynamic Dark
• 1x LS2 IRID Dynamic Dark photochromic visor (daylight track use only)
• 1x carrying backpack
• 1x tinted visor
• 1x pinlock Max Vision 120XLT
• 1x tear-off films

Size guide — all measurements