Stilo ST6 GT Carbon SA2025: Lighter, Cooler and Built to the Newest Snell Standard

 The Stilo ST6 GT Carbon SA2025 is Stilo's carbon fiber closed face helmet certified to Snell SA2025 and FIA 8859-2024, the newest standards for auto racing helmets. Compared with the ST5, Stilo says the ST6 line is 10% lighter, flows 26% more air and gives 11% more visibility. It comes in three shell sizes so each driver gets the smallest, lightest shell that fits.

The ST5 set the bar for closed-face helmets in GT and endurance racing. The ST6 keeps what drivers liked about it, including the side ports for radios and accessories, and rebuilds nearly everything else. Below we cover the carbon construction, the new ventilation, the upgrades over the ST5 and what SA2025 certification actually means for your next tech inspection.

What's New in the Stilo ST6 Compared With the ST5?

Short answer: The ST6 is lighter, better ventilated and easier to see out of than the ST5. It also adds a third shell size, a new visor system and updated certification.

The downward visibility gain is more useful than it sounds. A wider lower eyeport makes it easier to see your harness buckle during a driver change and to scan gauges without tilting your head.

The dual lock visor holds in both the fully closed and the cracked open vent position. That lets you vent the visor on a pace lap without it creeping open or shut.

Why Does Carbon Fiber Construction Matter in a Racing Helmet?

Short answer: Carbon fiber gives the shell high strength for very little mass. The ST6 GT Carbon passes the same Snell SA2025 impact tests as the composite version, but it does so in a noticeably lighter package.

What Is Stilo Puro Technology?

Puro is Stilo's carbon manufacturing process. It uses limited fillers, clearcoats and lacquers, so the shell carries less of the extra weight that paint and finish layers usually add. The result is a strong, thin carbon shell with a premium finish.

How Much Weight Do You Save?

Retailers list the ST6 GT Carbon at roughly 1,100 to 1,350 grams depending on shell size. One retailer puts the carbon shell about 270 grams lighter than the composite ST6.

That difference matters over a race stint. A lighter helmet is less mass for your neck to hold up under braking and cornering loads, which means less fatigue late in a long session. Three shell sizes help too, because a smaller head is not stuck carrying a shell built for a larger one.

Is a Carbon Helmet Stronger Than a Composite Helmet?

Both must pass the same certification tests, so both meet the same minimum protection standard. Carbon's advantage is strength-to-weight: it reaches that standard with less material. For drivers, that means equal certified protection with less weight on your head.

And Yes, It Looks the Part

Because Puro uses minimal finish layers, the carbon weave shows through in a polished, clean finish. It looks as good in the paddock photo as it performs on track, and it is a strong base for a custom paint design if you want one later.

How Does the ST6 Ventilation System Keep You Cool?

Short answer: The ST6 has a redesigned front intake and vents in the top of the shell that route air through channels in the EPS liner. Stilo rates the ST6 line at about 26% more airflow than the ST5.

Heat is one of the biggest causes of late-stint mistakes in a closed car. Sweat in your eyes, a fogging visor and rising core temperature all slow you down. The ST6 attacks that in three ways:

1. Redesigned front intake. Developed with input from F1 and endurance drivers, it moves more air across your face without compromising safety.

2. Top vents through the EPS. Air passes through channels in the impact liner, pulling heat and moisture away from your head.

3. Vented visor position. The dual-lock visor holds securely cracked open, adding airflow on cool-down laps and in the pits.

Can I Add Forced Air to the ST6?

Yes. The top vent holes accept a Stilo Top Air System, which feeds cool air from your car's fresh-air blower to the top of your head and across the inside of the visor. No drilling is required. Options include the Stilo Short Top Air System for Maglock, the Non-Adjustable Top Air System for Maglock and the Non-Adjustable Top Air System with Aluminum Oval Intake. Top Air kits come in sizes matched to the helmet shell, so choose the one for your shell size.

What Does Snell SA2025 Certification Mean?

Short answer: SA2025 is the newest Snell standard for auto racing helmets. It took effect October 1, 2025, and it is stricter than SA2020: helmets must pass a harder impact test while letting less force reach the head.

Snell updates its auto racing standard every five years. Two changes make SA2025 tougher than SA2020:

• Lower peak g limit. The maximum force allowed to reach the test headform dropped from 300 g to 275 g across all headform sizes.

• Higher impact energy. The first of the two impacts at each test site is now more severe, which is especially demanding for larger helmet sizes.

In plain terms, the test hits harder and the passing score is stricter. SA2025 also brings Snell's testing into alignment with FIA 8859-2024, which is why the ST6 GT Carbon carries both ratings.

What SA2025 does not add is rotational impact testing. Fire resistance, chin bar, shield and head-and-neck restraint anchor requirements continue from SA2020.

How Long Will an SA2025 Helmet Be Legal?

Most sanctioning bodies accept a Snell helmet for about 10 years from the standard's release. SA2025 helmets are expected to be eligible until around October 2035, compared with around October 2030 for SA2020. Always check your series rulebook, since each organization sets its own dates. Manufacturers will stop producing SA2020 helmets by the end of 2026.

For the full timeline and testing details, read our Snell SA2025 helmet certification guide.

Fit, Communications and Head-and-Neck Restraints

Short answer: The ST6 GT Carbon has an intermediate oval shape, comes in 8 sizes across 3 shells, and ships with M6 terminals for head-and-neck restraint anchors. The GT version includes earmuffs and is prepped for radio speakers.

How Should the ST6 Fit?

Measure around your head about one inch above your eyebrows and pick the size in centimeters. The intermediate oval shape suits most heads. A correct fit is snug, with cheek pads pressing firmly and no movement when you shake your head. If you sit between sizes, call us before ordering.

GT or FN: Which ST6 Do I Need?

The GT includes noise-reducing earmuffs and speaker cutouts for radio communication. It suits endurance racing and anyone running a radio. The FN is open-ear for maximum awareness and airflow. If you prefer a lower price over carbon, the Stilo ST6 FN Composite SA2025 shares the same ST6 design.

Does It Work With a HANS Device?

Yes. Every SA2025 helmet comes with M6 terminals installed for head-and-neck restraint anchors. Pair it with a device such as the HANS Sport 3. Our guide to head and neck restraints explains how they work.

What's in the Box?

Clear face shield, tear-off posts and a helmet bag. A radio intercom kit is sold separately.

Stilo ST6 GT Carbon SA2025 at a Glance

Ready to Upgrade to the ST6?

Shop the Stilo ST6 GT Carbon SA2025 helmet, or call our team at 844-438-7244 for help with sizing, a Top Air System or a matching head-and-neck restraint.

Frequently Asked Questions

Is the Stilo ST6 GT Carbon Snell SA2025 certified? Yes. It carries both Snell SA2025 and FIA 8859-2024 certification.

How much lighter is the ST6 than the ST5? Stilo rates the ST6 line about 10% lighter than the ST5, with three shell sizes to keep weight down for smaller heads.

Is a carbon helmet safer than a composite one? Both pass the same certification tests. Carbon's advantage is lower weight for the same certified protection.

Should I replace my SA2020 helmet now? Not necessarily. SA2020 helmets are expected to stay eligible until around 2030. Upgrade if your series requires it, your helmet has taken a hit, or you want the longest eligibility window.

Does the ST6 accept a forced air system? Yes. Stilo Top Air Systems fit the top vents without drilling.

What is the difference between the ST6 GT and ST6 FN? The GT has earmuffs and radio prep. The FN is open-ear for more awareness and airflow.

Do I need to replace a helmet after a crash? Yes. A helmet's protective capacity can be used up in a single impact, even with no visible damage.