MET Trenta 3K Carbon helmet review

MET's 30th anniversary continues with the Trenta 3K Carbon, which uses a carbon structure for improved safety, weight reduction and increased road performance over the standard model

MET Trenta 3K Carbon
(Image: © Graham Cottingham)

Cyclingnews Verdict

The Trenta 3K Carbon is very comfortable and well-ventilated but, for the price, it’s hard to justify over the standard Trenta or Trenta MIPS


  • +

    Superb ventilation

  • +

    Secure and even head retention

  • +

    Carbon structure is claimed to improve safety


  • -

    Cradle fouls on the inside of the helmet causing abrasions to the EPS

  • -

    Better in moulding coverage to protect vulnerable areas of the helmet

  • -


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Met developed the Trenta to celebrate its 30th anniversary and the Trenta 3K Carbon, as the name suggests, introduces carbon construction to create a lighter and safer helmet that MET describes as 'the most advanced road cycling helmet we have ever made'.

Design and aesthetics

The Trenta 3K Carbon sits as an aero all-rounder within the Met range and is sandwiched between the Manta with its minimal venting and the Rivale which is more about weight saving than cutting through the air. The Trenta helmet has quite a distinctive profile, cutting an elongated shape when viewed from the side - it's all very aero.

One of the first things that caught my eye on the Met Trenta is the scoop vent on the top of the helmet. This unusual intake is purportedly developed by NACA and its positioning creates a venturi effect to suck hot air out the reverse of the helmet, cooling the head without adding drag. Met says the exhausts at the rear have been optimised to be most effective when riding hard in the drops.

The top NACA vent doesn’t appear to have any physical channelling away from it so it’s effectiveness is hard to measure. However, this is clearly a feature that Met believe in as it features it on the Manta and Rivale helmets as well. 

As any point where the helmet makes contact can be a point of head build-up, keeping these areas to a minimum will aid airflow. The Trenta has been designed to make contact with only 30% of the head and features large channelling areas along the sides of the helmet leading to the rear as a passage for airflow. 

As with anything that is aerodynamic it’s not only the way the air hits a shape but also the influence of airflow as it leaves an object. Met used the wind-tunnel testing facilities and the Newton Laboratory of Milan to create a tail shape to help reduce drag and work with the front vents to create the aforementioned venturi effect. Met claims that when riding in a group, the Trenta will reduce drag by seven per cent compared to a regular helmet, however, this is one of those unquantifiable manufacturer measurements of performance that should be taken with a large pinch of salt. 

Performance and fit 

The Trenta 3K Carbon differs from the regular Trenta as it uses a carbon structure within the EPS liner. Met says that because the carbon is resistant to deforming it has been able to reduce the EPS foam density by 20 per cent, which reduces weight without affecting safety. In moulding has been used to protect some of the vulnerable areas for damage although it could offer a bit more protection.

Retention is handled by Met’s Safe-T Orbital retention system. The ratchet dial gives firm click for a good level of accuracy to fine-tuning fit. Further adjustments can be made with the option of four vertical positions and 2wo options for positioning the occipital pads. The retention system is also ponytail friendly for long hair and excessive lockdown growth alike.

Available separately, Met sells a rear light featuring multiple flashing modes which clips on to the rear retention system. Riders who often ride at night will really appreciate being able to mount a light as high up as possible as this makes a huge difference to visibility on the road. The small cover which stops water getting in the charger port doesn’t attach to the light itself so make sure to keep it safe while charging.

The Trenta 3K Carbon doesn’t come with MIPS or any alternative rotational safety system. If this is an essential feature for you, Met does offer the regular Trenta in a MIPS option.

The straps don’t feature any neat junctioning like some other helmets we have tested however the anchoring points give the straps plenty of clearance around the ears and jaw. With adjustment using secure clasps to refine positioning I didn’t ever feel them flapping and causing annoyance or irritation. 

There are two small grippers in the front vents for storing sunglasses although we found the narrow entrance into the vent didn’t play well with our selection of eyewear we had at hand. Possibly by coincidence but we found that sunglasses stored far more securely into the rear vents facing backwards. 

Riding experience

Ventilation is impressive and whether Met’s NACA vent actually does anything becomes a moot point as the helmet creates a good flow of air across the whole head. Airflow never feels breezy but even when moving slowly on a climb, hot air seemed to be dealt with before it builds up, exhausting out the rear before becoming a problem. 

The Met Trenta 3K Carbon offers a very comfortable fit as well. The Safe-T Orbital retention system cinches down extremely evenly around the head which provides a secure fit. The occipital pads which position on the back of the head feel just right but with the options of different positions can be fine-tuned.

One flaw I noticed is that with the occipital pads set in the wider position the retention system comes in contact with the EPS of the helmet. As there is no in moulding protection in this area the abrasions are quite noticeable although we are unable to determine if it might develop into something more than superficial without more use.

MET Trenta 3K Carbon

During the testing period the occipital pads rubbed against the EPS causing abrassion marks (Image credit: Graham Cottingham)


If you are looking for a performance road helmet that offers impressive levels of comfort and ventilation with some aerodynamic’s thrown in then the Trenta 3K Carbon is a great consideration. Whether the price difference between the top Trenta 3K Carbon model and the standard Trenta, which shares the same fit, ventilation and aero shape at the cost of around 15g, is justifiable is a decision you need to make yourself. To further confuse the situation, Met also offers the standard Trenta in a MIPS version that sits right in the middle.

Test conditions

  • Temperature range: Spring and summer, 2-20 degrees 
  • Test duration: Two months
  • Terrain: Road. gravel

Specifications: MET Trenta 3K Carbon 

  • RRP: £270 / €300 
  • Weight: 260g (actual, large)  
  • Rotational safety: No
  • Retention: MET Safe-T Orbital
  • Aero: Yes
  • Sizes: S, M, L 
  • Colours: 4

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