Specialized S-Works Prevail II Vent MIPS helmet review

The Prevail II Vent is Specialized's top-tier lightweight road bike helmet.

The original Prevail II was one of the first helmets to use the MIPS SL system, which forgoes the slip-plane enabling insert. Instead, the MIPS system, designed to reduce the transfer of rotational motion to your brain, is incorporated into minimalist pads.

This design is intended to have no effect on helmet volume, airflow or comfort – something often criticised in the original MIPS design.

The Prevail II was one of my favourite helmets to use, especially on warmer days. It was well vented, light, comfortable and featured the clever ANGi crash sensor, which combines with its app companion to alert your emergency contact should things go wrong.

Specialized S-Works Prevail II Vent MIPS helmet details and performance

The new Prevail II Vent comes ANGi-ready, but the ANGi sensor is now sold separately. I've switched the sensor over from my older helmet.

The Prevail II takes the lightness and comfort offered by the original helmet further.

The new helmet is essentially the same shape. Look closer, however, and you can see that the EPS foam core has had large sections removed.

Seven 'foam bridges' across the central vent and two outermost vents have been removed, leaving the aramid cord of the internal reinforcing skeleton exposed.

That means the already light 304g Prevail II is reduced to 266.4g in my large test sample.

The effect on cooling is impressive, with the helmet now effectively having three vents that run from the brow right back to the trailing edge.

I never felt the Prevail II was an especially warm helmet. I’ve been testing this one in the cooler early months of the year (riding it back-to-back with the older version) and it's significantly airier.

If you ride at speed and dip your head, you can feel a full-on chill.

The outer shell thankfully rolls over the exposed EPS edges.

That’s a positive feature, intended to prevent accidental damage and is especially relevant on expensive lightweight helmets.

I like the amount of adjustability in the straps and rear cradle (more than 4cm of vertical adjustment) and the lightweight silky material of the straps feels good against your skin.

The straps have a solid splitter that sat below my ears in the ideal spot, but there isn’t really any adjustment on offer, so I’d try before you buy.

The minimal rear cradle has a good micro-adjust dial with positive clicks, and its wide-set twin-anchor design means it's long-hair friendly too.

Specialized S-Works Prevail II Vent MIPS helmet bottom line

If you already own a Prevail II, the 40g weight saving (which is only 30g when you omit the ANGi sensor) and extra cooling probably won't be enough to justify the change.

If, however, you’re looking for a new lightweight, good-looking and great-performing helmet, then the Prevail II should be high on your list.

That's especially true because you can find the Prevail II Vent on offer at a much-reduced price.

This suggests Specialized may be bringing new updated premium S-Works road helmets to market in the not-too-distant future.