Being the lightest helmet isn’t always desirable, but somehow Specialized has checked every box with the new S-Works Prevail II Vent helmet while still being among the lightest helmets I’ve ever tested. As the name suggests, the Prevail II Vent is made to breathe and it does that quite well.
S-Works Prevail II Vent Helmet Features:
- Ultralight MIPS SL offers 10-15mm of unidirectional movement
- Aramid-reinforced skeleton
- Energy Optimized Multi-Density EPS construction
- Ultralight Mindset HairPort II micro-dial fit system
- ANGi Crash Sensor for added peace of mind
- Uses new 5th Dimension Cooling System
- Thin, soft, and lightweight 4X DryLite straps
- 5-star rating from Virginia Tech
- Weight: 285 grams (medium, actual)
- MSRP: $250

Feathery-light helmet for hot days
When cooler heads need to prevail, the S-Works Prevail II Vent is the obvious choice. With airflow that moves 18% faster than the standard Prevail II, the Prevail II Vent is made for ultimate cooling. To make this happen, Specialized engineers utilized an aramid skeleton that removes material that gets in the way of airflow, thus allowing more unobstructed ventilation — especially at higher speeds. That braided aramid structure also keeps the multi-density EPS foam connected for 360-degree protection.
Two different EPS foam colors were used to showcase the different densities. The center section is charcoal while the sides are lighter grey in color. With that, side impacts are better absorbed and ultimately the MIPS SL system then can act as a second layer of brain protection to cushion impacts and reduce the forces that your brain has to absorb. The “watch” attachment points attach the pads at strategic locations to allow the proper rotational movement upon impact. These pads are attached with velcro dots for removal, if needed. But, I’d hold off playing around with them and instead wash the pads in place throughout the helmet’s lifetime.

I began testing the S-Works Prevail II Vent in the spring, with morning temperatures in the low-40’s. I have to admit that I passed it over on one particularly-cold morning and instead went with the Bolle Furo MIPS, due to it’s vent covers. The next day, I put on my big boy boots and decided to endure the chill with the Prevail II Vent. No question, you’re not going to want to wear this helmet on the coldest rides without at least a cycling cap. Clearly, that’s not the intended purpose of this helmet. No, it’s made for the hottest of days in the saddle.
As I have discovered, on the hottest of days, there’s no finer helmet than the S-Works Prevail II Vent. How does this helmet perform so well in the heat, you ask? Specialized claims that this is the most airy helmet they have ever made, with 18% faster airflow than the standard Prevail II. I’m here to say that those claims are absolutely true! I can’t think of a better helmet for even the hottest days. With a shaved head, I can feel every nuance regarding helmet performant and airflow and the proof is in the pudding… err… airflow.

To further lighten the helmet, there’s more exposed foam, but not in common wear areas, like the rim. The rear and some areas of the side of the helmet are exposed to damage from allowing the Prevail II Vent to roll around in the back of the Subaru. My advice: take care of this helmet. It is a high-tech, purpose-built helmet that does require special care. You don’t park a Ferrari in just any parking space, so don’t just toss this fine piece of equipment around.
The light and thin straps are ultra-comfortable. Something nice about them is how they attach to the helmet. Instead of just threading through the shell in a loose fashion, they are hard-mounted to the rim at fixed mounting points. This eliminates twisting and frustration when trying to put the helmet on. It’s easy to get the straps out of the way and slide the helmet in place. Interestingly, the strap yokes are fixed, but the sit just right on my face (hopefully they also work pretty universally for others). A simple buckle with traditional strap adjustments ensure the Prevail II Vent fits nicely.

Rounding out the fit of this helmet, I’d say it fits an oval-shaped head just right. I don’t have any pressure points and the micro-fit dial system allows for quick fit adjustments. It’s a good fit system, but instead of tightening the helmet evenly around the circumference of your head, it does push the head forward as it is tightened. And, that little knob is pretty miniscule. Sometimes the fit systems do interfere with sunglasses, but I didn’t have any issues with the Koo Demos, Tifosi Sledge or Smith Attack Max sunglasses during testing. In addition, the vents offer the perfect perch for sunglasses when not in use (see above).
Sweat management is always a factor with every helmet. I’d say it’s pretty good, but not perfect. During hard efforts, I will get drips into my sunglasses. It’s not a river of sweat, but it does drip. The best helmet I’ve tested for sweat management is the Giro Helios Spherical MIPS.
Luckily, I haven’t crash-tested this flavor of MIPS, but I have experienced a crash with traditional MIPS. I’m a believer and don’t have any doubt that MIPS SL will perform just as well as the original.
This helmet is ANGi-equipped to notify loved ones in the event of a crash. To use it, you must open the Specialized Ride App, pair your ANGi and then pair your head unit. Each time you start your ride, you need to open the Ride app, but you can then start/stop your ride on your head unit, like the Wahoo ELEMNT ROAM. It would be nice to have it just sync directly with your GPS.
The Good
- Instantly disappears
- So breezy and cool on hot days
- Thin straps sit comfortably
- MIPS SL saves weight and still protects upon impact
- Secure sunglass storage
- Easy fit adjustments
- Includes ANGi system
- Quiet at speed
The Bad
- Very cold on early mornings
- Micro dial could be a little larger
- ANGi is nice, but should sync directly with Wahoo
- ANGi taps on the back of the helmet on rough terrain
The Bottom Line: S-Works Prevail II Vent
For hot summer days, the S-Works Prevail II Vent Helmet is the obvious choice. It’s so airy that bugs fly right through the vents and you are cooler and fresher as a result. It is a lightweight helmet, but not so light that safety is compromised. The overall fit and function of the Prevail II Vent is exceptional and the MIPS SL system looks to provide just as good of performance as the original.
Buy Now: Available from CompetitiveCyclist.com