Wind Tunnel is the graphic family built around flow lines, and B3 is its fluorescent version — the most visible helmet in the Thunder 4 R SV range by a clear margin.

What this helmet is — and what changed for the R

🔵 The generation change matters when reading reviews. Everything published about the „Thunder 4 SV" describes the previous helmet; this is the 4 R, with different intakes, a different spoiler and a revised visor mechanism.

No independent test of the 4 R exists yet. MCN's 4/5 belongs to the model it replaced.

About the Wind Tunnel B3 graphic

Fluorescent pigments convert ultraviolet into visible light, which is why they appear to glow rather than merely to be bright — and why they keep working in exactly the conditions where ordinary colours fail: overcast mornings, dusk, rain, and the flat grey of a winter commute. On a helmet ridden in traffic every day, that is a functional argument rather than a styling one. The Wind Tunnel drawing keeps it from looking like workwear by breaking the colour across the shell rather than presenting one flat slab. 🔵 Fluorescent fades faster than any other pigment type under sustained sun — storage out of direct light is the only thing that slows it.

The SHARP stars that belong to a different Thunder

Absence of a rating is not evidence of poor performance — SHARP tests a small subset of the market and buys helmets at retail to do it. Plenty of good helmets have never been through it.

🔵 What matters here is not confusing this helmet with the older MT Thunder or Thunder 3, both of which do carry four stars and neither of which is this helmet.

HIRP, two shells and ECE 22.06

🔵 A note on the weight figure. MT quotes no separate number for the Thunder 4 R; the ~1500 g ±50 here is the documented weight of the Thunder 4 SV and the shared HIRP platform.

Treat it as an indication rather than a measurement until MT publishes a 4 R spec sheet.

MT-QVSS, the visor lock and the Pinlock in the box

🔵 Tool-free visor changes matter more than they sound on a commuting helmet. A visor that needs a screwdriver is a visor that never gets changed, and a scratched one flares badly against oncoming headlights at night.

MT-QVSS makes it a ten-second job, and the visor is the MT-V-28C on the MT-M-28X mechanism.

The integrated sun visor

If you wear prescription glasses, a drop-down shield is considerably more practical than prescription sunglasses or a tinted visor — it goes up and down without removing anything.

🔵 On this helmet it deploys from a single slider and retracts completely out of the way.

Enlarged intakes and a revised spoiler

The revised spoiler works alongside the intakes rather than separately. A spoiler manages the low-pressure wake behind the helmet, and that wake is what pulls air through the exhausts — so reshaping it changes the airflow as well as the stability.

🔵 Both were changed for the 4 R over the Thunder 4 SV.

Interior, fit and retention

A micrometric ratchet is faster than a double-D ring and adjustable in finer steps, which is what you want on a commuting helmet put on and taken off twice a day — and it works in winter gloves, which a double-D genuinely does not.

🔵 The trade is that a ratchet has an adjustment which can drift. Check it periodically.

Intercom preparation and speaker pockets

MT's MT-B01 (Rider Sync) is designed around this shell, which means the cable routing and the speaker positions are accounted for rather than improvised. A third-party unit will physically work; it will not use any of that.

🔵 Neither is supplied with the helmet.

Where it sits in MT's range

MT's range is unusually consistent: almost everything is built on the HIRP platform, with the carbon KRE+ S as the single exception. What changes between models is the body type and the equipment rather than the construction.

🔵 This one is the everyday full-face, with a sun visor, tool-free visor changes and intercom preparation.

When something wears out

Helmets are consumables with a long life rather than permanent objects. MT, like every manufacturer, recommends replacement after around five years of use regardless of condition — and immediately after any real impact, because the EPS crushes once and does not recover.

Between those points, everything you touch on this helmet is replaceable.

In the box

• MT Thunder 4 R SV helmet — Wind Tunnel B3 (HIRP shell)
• Clear MT-V-28C visor, fitted
• Pinlock® DKS435 MaxVision anti-fog insert
• Nose deflector
• 🔵 No intercom — the helmet is prepared for the MT-B01 Rider Sync system; the system is a separate purchase

Size guide

Specification

• Model — MT-Helmets Thunder 4 R SV
• Part number — 1375D50B3203
• Colour — Wind Tunnel B3 — Matt, neon yellow
• Homologation — ECE 22.06 — the current European standard
• 🔴 Safety rating — none. SHARP's four-star „MT Thunder" and „MT Thunder 3" are different, earlier models; the Thunder 4, 4 SV and 4 R have not been tested. No ADAC or Snell result either
• Independent verdict — MOTORCYCLE NEWS 4/5 — 🔴 for the predecessor Thunder 4 SV („surprisingly good for less than £120"), which named ventilation as its main weakness. No test of the 4 R exists yet
• Helmet type — Full-face, everyday / commuting
• Shell — HIRP (High Impact Resistant Polymer); two outer shell sizes
• Weight — approx. 1500 g ±50 — 🔴 MT publishes no separate figure for the 4 R; this is the documented Thunder 4 SV / HIRP-platform weight
• Sizes — XS to 3XL (seven sizes)
• Visor — MT-V-28C on the MT-M-28X mechanism, with MT-QVSS tool-free quick swap and a lock against unintended opening
• Anti-fog — Pinlock® DKS435 MaxVision included as standard
• Sun visor — integrated drop-down, single slider, retracts fully into the shell
• Ventilation — enlarged intakes and a revised spoiler for this generation — MT's answer to the criticism levelled at the Thunder 4 SV
• Retention — micrometric ratchet buckle
• Interior — fully removable and washable, with dedicated speaker pockets
• Communication — prepared for MT-B01 (MT Rider Sync) — system sold separately
• Also supplied — nose deflector
• Impact liner — expanded polystyrene — crushes once and does not recover; replace the helmet after any real impact
• Serviceability — visor, Pinlock lens, lining, cheek pads, sun visor and nose deflector all available separately
• Replacement guidance — after around five years of use regardless of condition, and immediately after any impact
• Manufacturer — MT-Helmets (MT Helmets, Spain)
• Sizing note — measure around the widest part of your head, about 1–2 cm above the eyebrows. With two outer shell sizes, try the size the chart gives you rather than ordering by tape alone — the fit at the shell boundary is less precise than on a three-shell helmet
• Made for — commuting, everyday riding and country roads at ordinary speeds — not a long-distance touring or track helmet
• Care — wash the lining by hand a few times a season; never wipe the visor or the sun visor dry, as road dust scratches both permanently

• 1x MT Thunder 4 R SV helmet
• 1x MT-V-28C clear visor (Pinlock Max Vision ready)
• 1x Pinlock DKS435 anti-fog insert
• 1x nose deflector
• Integrated drop-down sun visor (built in)