At road.cc every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.What the road.cc scores mean
Good scores are more common than bad, because fortunately good products are more common than bad.
The Specialized S-Works Prevail II Vent is a better-vented version of the company's top-end vented helmet. It is cool, comfortable and fits very well, plus you still get the safety benefits of MIPS and ANGi technologies should you have an off.
Specialized has probably looked at the world of smartphone tech and decided that incremental changes make for good business because the American brand has come out with lots of iterations of its main products. Here it has made a more airy version of its top-end vented helmet, the Prevail II (note, no Vent), by using aramid struts that turn that helmet's ten big vents into three huge ones. Specialized claims this change means it'll move air across your head 18 per cent faster than the non-Vent Prevail II.
With my hair set to wavy mode and calibrated for waft, I headed out before I went on an actual ride to see if I could tell the difference. The results? A marginally more frozen head on a January morning with the Prevail II Vent than with the standard Prevail II.
With that highly scientific testing done, I put a warming hat on under the Prevail II Vent and set off for an actual ride. I found the standard Prevail II to be very comfortable, that is until I crashed on my head halfway through last year and changed the shape of the helmet. The Vent keeps that (pre-crash) comfort and is an easy lid to wear on longer rides.
On my head the Vent sits quite low, with the front rim dropping to just above my eyebrows. How it sits on you will depend on your head shape, but if you're looking for a bit of extra skull coverage, it could be a good option. The retention system provides plenty of adjustment at the rear.
Specialized opts for a fixed splitter on the straps, which doesn't work for everyone. On me, they sit just below the ear and are perfectly comfortable, but there is one thing I would change about the strap design and that is the anchoring point. I'd like it to be on the inner edge of the helmet shell, rather than in the middle. The current middle position leaves both split straps sitting away from my face if I don't wear sunnies, and the rear split strap sits out regardless. At higher speeds, the wind gets at the split straps and causes them to buzz against the cheekbones. It's a minor annoyance, but one that I don't have with other helmets.
The internal MIPS liner didn't irritate me while riding and it does help the helmet to gain a five-star safety rating from the Virginia Tech team.
We can argue about helmet safety all you like but for me, a MIPS-equipped lid is worth the marginal weight penalty as the data is there to show a reduction in rotational forces acting on the brain in the event of a crash. I like my head, so I'll take that.
Another safety feature, though not one that I use myself, is the ANGi device on the back of the Vent. Specialized says that it'll detect a crash if you have one and then contact a nominated number without you needing to be conscious. My issue with it is that it needs to be connected to the app and then the app needs to be running on your phone in the background. If my head wasn't fixed to my body I'd forget to take it with me, so it's probably not something that I'd remember to be doing before each ride. And also, I wasn't about to go and do another head skid to test if it works. Anyway, it's there if you want it and easy to remove if you don't.
Price-wise, it is £20 more than the standard Prevail II and you can easily get a comfy road lid for less – the Lazer Z1 MIPS is a favourite of mine, now up from £169.99 when George tested it in 2020 to £209.99 – but equally, you can spend more – the Met Trenta 3K Carbon is £270, while the Giro Aether MIPS is £289.99.
If you've got the cash for the Prevail II Vent, you won't be disappointed. Everything that was good about the standard Prevail II is here, it's just a bit more breathable. Overall, it's a superb vented helmet, even if it does sit in the upper range of what many will be willing to pay.
Airy and comfortable, this is a top-end road helmet with good safety features
If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website
road.cc test report
Make and model: Specialized S-Works Prevail II Vent
Size tested: Medium, 55-59cm
Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
"Cooler heads will always prevail. The new S-Works Prevail II Vent's massive cooling power helps better regulate your body's temperature to keep you cooler so that you'll always be ready when your ride heats up.
"We took everything that the S-Works Prevail II was doing right, and did it even better. One of the greatest benefits resulted from the removal of a total of seven foam 'bridges' from the center and sides to create more effective ventilation channels. These expanded channels move air across your head 18% faster than the original Prevail II. The faster air moves across your head, the faster heat is whisked away from your head and the cooler you remain''it's called 'convective heat transfer'. This all adds up to the coolest helmet we've ever made."
Tell us some more about the technical aspects of the product?
The new 5th Dimension Cooling System, with its redesigned, patented, aramid-reinforced skeleton, provides internal EPS support allowing for 20% larger vents with deep internal channels and aligned exhaust ports.
Our ultralight and supremely comfortable version of MIPS, MIPS SL, has only gotten better. We've added perforations, along with a ripstop mesh to maximize breathability and performance. With MIPS SL, we've essentially integrated MIPS technology within the helmet padding itself. MIPS SL's minimalist "watchband" attachment system provides 10 to 15 millimeters of rotation in every direction and offers the same brain protection benefits as other versions of MIPS, while also ushering in a new level of comfort and weight savings.
Patented Energy Optimized Multi-Density EPS construction helps to manage impact energy.
Ultralight Mindset HairPort II micro-dial fit system with height adjustability for the perfect fit.
Thin, soft, and lightweight 4X DryLite webbing won't stretch out with sweat or water.
Tri-Fix web splitter improves comfort and ease of strap adjustments, while an in-strap webbing system delivers ultralight construction and security.
Five Star Virginia Tech® Helmet Rating ™''Virginia Polytechnic Institute and State University awarded the helmet its highest rating of five stars.
This helmet is ANGi ready, with a fit system mount designed for easy integration with our ANGi crash sensor.
Our available aftermarket ANGi sensor gives you and your loved ones peace of mind like never before. When combined with our Specialized Ride app, the ANGi sensor will evaluate the forces acting on the helmet in the event of an accident and, if necessary, send a text message to your specified contacts with your location.
Tell us how the product performed overall when used for its designed purpose
Very well. It is cool and comfortable.
Tell us what you particularly liked about the product
This is just a very comfortable road helmet, making it great for long days on the bike.
Tell us what you particularly disliked about the product
A minor point, but I'd like the straps to anchor closer to the head.
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
The Lazer Z1 Mips is £209.99 while the Abus AirBreaker is £229.99, but without MIPS. It is cheaper than the Met Trenta 3K Carbon (£270) and the Giro Aether MIPS (£289.99).
Did you enjoy using the product? It's an easy helmet to love.
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
It's a bit better than the already excellent standard Prevail II; I wouldn't say the changes made warrant an 'exceptional' mark, but it is certainly excellent.
About the tester
I usually ride: Specialized S-Works Tarmac SL7 My best bike is:
I've been riding for: Under 5 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, club rides, general fitness riding, I specialise in the Cafe Ride!
Son of a Marathon runner, Nephew of a National 24hr Champion, the racing genetics have completely passed him by. After joining the road.cc staff in 2016 as a reviewer, Liam quickly started writing feature articles and news pieces. After a little time living in Canada, where he spent most of his time eating poutine, Liam returned with the launch of DealClincher, taking over the Editor role at the start of 2018. At the weekend, Liam can be found racing on the road both in the UK and abroad, though he prefers the muddy fields of cyclocross. To date, his biggest race win is to the front of the cafe queue.