Wind tunnel examined: Which aero street bike helmets are the quickest?

When shopping for a street bike helmet, your main motivation almost certainly pertains to security. In the occasion of a crash, the added safety provided by an authorized helmet will be the distinction between strolling away with little greater than your ego bruised and, properly, not strolling away in any respect. 

But there is not a easy reply as to whether one helmet is safer than the following. There are a choose few third events that carry out unbiased assessments, however at an trade stage all we all know is that they’ve met the related native authority’s minimal commonplace, which, manufacturers inform us, is a low bar. 

As a end result, selecting which helmet to purchase is commonly a steadiness of different components. Ventilation is necessary for many who dwell in hotter climates. Weight might be a key issue for mountain goats who spend their lives using uphill. The fashion-conscious will prioritise the way it appears to be like, however for almost all of us, the necessary metric might be aerodynamics. Who would not need to go sooner for much less effort?

Around a decade in the past, the class of aero street helmets sprung into life, and nowadays some take an unambiguously aero strategy to their design, with lengthy tails and closed-off frontal profiles. Others take a extra refined strategy, with a extra rounded rear and some vents up entrance. 

Given their go-faster intentions, it isn’t unusual for an aero helmet to be launched with claims of being some watts extra aerodynamic than that different helmet, or any variety of seconds sooner than one thing else over a 40km time trial. Those comparisons normally relate to a model’s outgoing mannequin or different merchandise within the lineup; not often will they name out the competitors. 

As a end result, there is not a lot info on the market that compares throughout manufacturers, such because the Specialized Evade in opposition to the Trek Ballista, or the Met Manta in opposition to the Giro Eclipse. 

Luckily, that is the place we are available in! 

We took 23* completely different helmets from 18 manufacturers to the wind tunnel for a back-to-back check to search out out which was quickest (and which was slowest!). We additionally ran some further assessments on sun shades, gloves and extra, which we’ll share within the coming weeks. 

*We really took 24 helmets, however one was an unreleased helmet that launches later this 12 months. We examined it beneath the promise of preserving the outcomes to ourselves till then. I’m afraid that is all you may hear about it till it does. 

Before we get into the info, a fast interlude to say that this function isn’t sponsored and we paid the conventional business charge for our wind tunnel entry. This content material was made potential solely and fully by our paying subscribers.

The helmets

Of all of the helmets we took, the bulk had been described as aero helmets by their respective model and fell someplace on the spectrum between ‘all-out aero’ (such because the Trek Ballista or S-Works Evade) and ‘aero all-rounder’ (just like the Giro Eclipse or POC Ventral). 

A small quantity can be classed as ‘vented’ helmets, as a result of we additionally needed to get a really feel for the distinction between the ‘vented’ and ‘aero’ classes as collectives. In alphabetical order, they’re as follows:

Aero helmets

• ABUS Gamechanger 
• Carnac Evo
• Giro Eclipse
• Julbo Sprint
• Kask Elemento
• Kask Utopia Y
• Lazer Vento Kineticore
• Limar Air Atlas
• MET Manta
• Oakley ARO7 (examined twice – with and with out visor)
• POC Procen Air (examined twice – with and with out visor)
• POC Ventral
• POC Ventral Tempus
• Rudy Project Nytron
• Scott Cadence
• Smith Ignite
• Specialized S-Works Evade III
• Sweet Protection Tucker 2VI
• Trek Ballista
• Van Rysel FCR 

Vented helmets

• Specialized S-Works Prevail III
• Trek Velocis
• Uvex Rise Pro

Each helmet was measurement medium.

The determination course of for selecting which helmets to check was primarily based on our analysis of every model’s finest out there choice(s) in the marketplace on the time of testing; what’s getting used within the WorldTour; and which helmets we expect folks will contemplate when deciding to purchase. 

It was restricted, to some extent, by what we might get our fingers on. For instance, we needed to incorporate the Ekoi Aerodinamica however our a number of makes an attempt to contact the model went unanswered. We additionally tried to get the brand new Kask helmet (the one which goes down over the ears), however neither Kask nor Ineos had a spare they may mortgage us.

The check

We took the helmets to the wind tunnel on the Silverstone Sports Engineering Hub, testing the aerodynamic efficiency of every helmet. 

Naturally, the check was standardised, that means the identical situations had been met for every information seize. These included the identical bike (Pinarello Dogma X), rider, package (Santini Viper skinsuit, Velotoze overshoes, Oakley Radar glasses), wind pace and extra. 

We ensured every helmet was sitting stage earlier than every run, and the straps for every helmet had been clear in opposition to our mannequin’s face with none strap ‘tail’ (which might flap and skew the outcomes). The wind tunnel itself was additionally put by way of a taring course of earlier than every seize to make sure accuracy. 

The protocol was designed on my own, with steerage from aero consultants Casper von Folsach within the run-up and Huw Williams on the day. 

Pedalling the bike was Cyclingnews Tech Writer and beginner racer, Tom Wieckowski. We needed to attempt to get as near an actual rider as potential, so we accepted the (monetary) value of working longer captures with an actual individual to get a extra sensible end result, relatively than utilizing a static model.

Tom’s place on the bike was captured in an preliminary baseline check, after which a top level view of that place was projected onto the ground in entrance of him for the remainder of the day. This supplied an correct cue for Tom to stay in place throughout subsequent runs. We additionally examined for positional drift, which comprised a number of assessments with the identical helmet to work out how a lot distinction there could possibly be between two an identical setups, and thus how a lot blur we should always settle for in our outcomes. 

We examined every helmet at 40km/h (24.85mph). This is reflective of excellent amateur-level racing speeds, however the ensuing CdA information might be priceless in any respect speeds. In the outcomes beneath, I’ve extrapolated the info to supply the ability required at 30, 40 and 50km/h, the pace anticipated at 250, 350 and 450 watts, and the way these speeds relate to a 40km time trial.

Each information seize was carried out in five-degree increments from 0 to +15 levels yaw. That means 4 seize factors of 0, +5, +10 and +15 levels. Helmets are symmetrical, so there was no have to seize the info at unfavourable yaw angles too. Each helmet was examined in a sweep in the identical optimistic path (0 to fifteen) for consistency and held for 30 seconds per seize. 

The wind tunnel itself was operated by skilled Engineering Technician Huw Williams and is designed to account for any modifications in temperature or air density in its outcomes.

Holding the bike in place was a set of stanchions, and no corrections had been made for these, since they had been the identical throughout all assessments. We’re primarily within the distinction between helmets right here, not absolutely the values.

Some caveats

We’ve examined the aerodynamics right here, so we’ve the CdA determine for every helmet at 4 completely different angles of yaw. With the typical determine, we have accomplished some calculations to resolve for energy (watts) at completely different speeds, for pace at completely different powers, and the time saved over a 40km course the place all different components stay equal. These calculations don’t think about further losses reminiscent of drivetrain friction or rolling resistance, however we’re solely within the variations right here, relatively than absolute values.

Our rider Tom’s positional drift equated to 1.19%. As a end result, every end result inside 1.19% of one other ought to bear this in thoughts, because it might merely be a results of this. We will proceed to share the testing outcomes as they had been obtained for simplicity.

The outcomes of our testing are consultant of simply that: our testing. We perceive that helmet manufacturers may see completely different outcomes primarily based on completely different assessments or completely different protocols. We do not intend to assert that our outcomes are the ultimate phrase in helmet aero testing, however relatively a further stream of unbiased, unbiased testing and knowledge for Cyclingnews readers. 

We perceive that the aerodynamic efficiency of a helmet can differ from individual to individual relying on the way it interacts with the physique. We sat Tom in a fairly relaxed ‘hoods’ place, reflecting an all-day using place, in order that the helmet would sit larger away from his physique to minimise this connection. 

We additionally perceive that there are different components that come into play when shopping for an aero street bike helmet. For instance, how properly it’s going to defend you within the occasion of a crash, how snug it’s, its air flow properties, its weight, its fashion, and the way properly it performs with glasses are simply a few of the different components it is best to contemplate when deciding which to decide on.

The outcomes

For every helmet, we are going to record the CdA for all 4 yaw angles, together with the typical and an accompanying line graph. We will order the helmets utilizing the typical from quickest to slowest. 

We will then use it to calculate the ability required to experience at 30km/h (18.64mph), 40km/h (24.85mph), and 50km/h (31.07mph) utilizing the next calculation: 

Power (watts) = 0.5 x AirDensity x CdA x Velocity^3

We will even calculate the anticipated pace if using at 250 watts and 350 watts utilizing the next calculation: 

Speed (km/h) = 3.6 x ((Power / (0.5 x AirDensity x CdA)) ^⅓)

We will then apply this pace to calculate how lengthy it might take to cowl a 40km course. The calculation for this assumes ideally suited situations and so components reminiscent of wind, elevation, cornering, drivetrain effectivity, rolling resistance, acceleration, and so on are all completely equal. Again, we’re highlighting the variations right here, we’re not interested by absolute values. 

The leads to temporary

Detailed outcomes, ordered by common CdA

1. Poc Procen Air (w/ Visor)

The winner of the Cyclingnews wind tunnel aero helmets check, when you think about the typical CdA throughout the 4 yaw angles, is the POC Procen Air full with visor. 

It’s the helmet that the EF Education-StraightforwardPost males’s workforce and EF Education-Cannondale ladies’s workforce have been utilizing within the WorldTour this season, and was designed at the side of riders from the workforce. 

It’s unsurprising as a result of the Procen Air might be higher described as a time trial helmet tailored for the street. Aesthetically, it would not conform to what most individuals would describe as an aero helmet, and to be completely trustworthy, you may really feel a bit of bit foolish in the event you turned as much as a neighborhood membership experience sporting one. 

If you had been to carry 250 watts for a 40km time trial, it might prevent 55 seconds in comparison with the slowest helmet in our check, or in the event you had been to experience at 40km/h, it might prevent 12.76 watts.

On common, it’s seven seconds sooner over 40km than the 2nd place S-Works Evade III when using at 250w. It can be 10 seconds sooner with the visor than with out it. 

However, whenever you look nearer on the CdA information on the particular yaw angles, the successful margin turns into a bit of extra blurred. At each 0 levels of yaw (ie no crosswind in any respect) and 15 levels of yaw (various crosswind), the Procen Air performs excellently, however in between at 5 and 10 levels, the S-Works Evade III edges forward. 

2. Specialized S-Works Evade III

Second place goes to the Specialized S-Works Evade III, with a mean CdA of 0.3523. This is a strong efficiency and, given the TT heritage and divisive aesthetic of the POC Procen Air, it is maybe the helmet that many individuals will contemplate the one to purchase. 

Compared to the slowest on check, the Evade III will prevent 47 seconds in a 40km TT (at 250 watts). However, when in comparison with the Procen, you may be eight seconds slower, and must put out an additional 1.8 watts to carry 40km/h. With that mentioned, the info at 5 and 10 levels of yaw really put the Specialized on high, so the fact is probably going much less clear lower. 

3. POC Procen Air w/out Visor

Interestingly, whenever you take away the POC Procen Air’s visor, it is nonetheless among the many quickest helmets in our check, however with a mean CdA of 0.3529, you give away 10 seconds in that 40km TT, or it’s essential pedal 2.3 watts tougher to realize 40km/h. 

Of course, sporting the visor may improve the temperature, and this information would not account for any modifications to your consolation or core temperature, so there are caveats to the end result. 

4. Scott Cadence

Next up, rolling into a powerful fourth place is the not too long ago renewed Scott Cadence with a mean CdA of 0.3531. This is the helmet that the Team DSM Firmenich Post NL workforce have been sporting this season, and was worn by Pfeiffer Georgi to her first ever Paris-Roubaix podium.

This will prevent 10.29 watts at 40km/h when in comparison with the slowest on check, or in the event you had been to carry 250 watts in our arbitrary 40km time trial, you’d arrive on the end 44 seconds sooner. However, you’d end three seconds slower than in the event you had worn the S-Works Evade above. 

5. Van Rysel FCR

Sneaking into a really shut and massively spectacular fifth place is the Van Rysel FCR, with a mean CdA of 0.3531; precisely the identical because the Scott Cadence. 

We needed to record them so as, although, so we went all the way down to extra decimal locations to separate these two, however what it means in the true world is that both helmet gives nearly an identical aero efficiency. Looking on the particular yaw angles, the Cadence is marginally sooner at 0, 5 and 10, however when the crosswinds begin to blow, it stalls and the FCR steps up. 

However, one very huge issue to keep in mind is the value. At simply £89.99, this helmet undercuts most others on the check by a major margin. The Cadence will set you again nearly 3 times as a lot, whereas the successful helmet on this check is greater than FOUR occasions costlier at £360.00. 

If you are searching for aero efficiency at a value, this needs to be in your record. 

6. Giro Eclipse

Next up, rolling into sixth place is one other shock performer. The Giro Eclipse, which at the moment sits on the very high of Virginia Tech’s unbiased influence check desk, appears to be like extra like a vented helmet than a devoted aero helmet, however in our testing, it carried out properly with a mean CdA of 0.3541. 

This would prevent 40 seconds versus the slowest on check in a 40km time trial, however would lose you 14 seconds when in comparison with the winner. 

As we have present in our finest street bike helmets shopping for information, lots of people discover themselves torn between this and the S-Works Prevail III, as they each carried out properly within the Virginia Tech check. In my very own expertise, the air flow of the Specialized is leagues forward, however aerodynamically the Giro would prevent a not-insignificant 3.87 watts at 40km/h. 

7. Trek Ballista

In seventh place is the newest model of the Trek Ballista, an aero helmet that undoubtedly shouts ‘aero’ in the way in which that it appears to be like. The efficiency would not fairly match its unashamed aesthetic in opposition to just a few of the others right here, however with a mean CdA of 0.3542, it’s going to prevent 9.38 watts in comparison with the slowest on check at 40km/h, and 40 seconds in a 40km TT. 

8. Trek Velocis

Perhaps extra of a stunning end result within the Trek camp is the Velocis, with a mean CdA of 0.3549. This means it’s going to end simply three seconds slower than the Ballista, otherwise you’d have to generate a bit of over half a watt extra to maintain 40km/h. 

Given its unashamed aero form with lengthy tail, we would hazard a guess that the Ballista would check sooner in a extra aggressive aero place, so it’d nonetheless be the helmet of alternative for solo breakaway artists, however for these of you using in a number of positions in various situations, it is a nice alternative. 

9. Julbo Sprint

In ninth place, rolling comfortably on the entrance finish of a mid-table end, is the French model Julbo with its Sprint helmet, with a mean CdA of 0.3560. This helmet is being utilized by the Groupama FDJ males’s workforce this season, and in comparison with a few of the different fashions proven right here, is a fairly priced affair at €149.90. 

Interestingly, Groupama had been sporting Giro Eclipse helmets earlier than partnering with Julbo, and primarily based on our testing, that transfer value them round three watts (on the sooner peloton speeds of 50km/h), though we perceive that completely different riders in numerous positions may even see completely different outcomes. 

10. Kask Utopia Y

In tenth place is the primary of two helmets from Italian model Kask, with the Utopia Y aero helmet. 

The Utopia Y is the minimally up to date model of the unique Utopia helmet, which has been round for greater than 5 years, so given the age of the design it is possibly not a large shock to see it battle to problem the newer merchandise. 

Compared to the successful POC Procen Air, you’d have to generate a further 5.1 watts to maintain 40km/h. Bump that as much as 50km/h and that distinction grows to just about 10 watts. Compared to the extra road-style S-Works Evade III, you’d end a 40km time trial 15 seconds off the tempo. 

With all that mentioned, Kask has a brand new aero helmet on the way in which. Rumours inform us that it is known as the Nirvana, however you most likely realize it as ‘the one which comes down over the ears’. It’s been in use by Ineos Grenadiers to this point this season, and regardless of our greatest makes an attempt to pay money for a pattern for this check, neither Kask or Ineos had been capable of assist. 

11. Lazer Vento Kineticore

Just lacking out on a top-10 efficiency is the Shimano offshoot, Lazer, with its Vento Kineticore helmet. The Kineticore brings some novel concepts to the helmet design desk, not least the Kineticore expertise itself, which moulds the interior EPS foam into blocks that may shear and break within the occasion of a crash, providing superior rotational influence safety when in comparison with a regular EPS development, in addition to further airflow inside. 

It additionally replaces the dial retention tightening system with a ‘Scrollsys’ rolling belt that is built-in cleanly into the again of the helmet, in addition to a twist-in rear gentle that provides versatility for these using past daylight. 

It won’t be the quickest helmet on this check, nevertheless it’s removed from the slowest and there are a handful of different causes to purchase it. 

12. MET Manta

Given MET sponsor the UAE Team Emirates squad, the MET Manta is often seen atop the pinnacle of Slovenian famous person, Tadej Pogačar. It comes with a MIPS liner, albeit the much less inconspicuous variant that places a bodily liner between the pinnacle and the EPS foam. 

The end result right here is considerably stunning, given Met has entry to its personal wind tunnel, however we’ll take a second right here to remind everybody that the outcomes might range barely from rider to rider. 

With that mentioned, our check places the Manta into twelfth place, which is a strong mid-table end result and one which beats out helmets a lot pricier and way more geared in direction of the aero design. 

13. Smith Ignite

In thirteenth place, the Smith Ignite stands out for one major purpose: Koroyd. While some helmets make use of MIPS for rotational influence safety, and others create their very own designs, reminiscent of Lazer’s Kineticore, Smith appears to be like to Koroyd. 

This is a cloth that resembles a set of straws bunched collectively, and it’s mentioned to permit shearing and compression at varied angles, to extend security. In our expertise, it does include downsides although, together with a decreased airflow and an lack of ability to scratch your head. 

Regardless, the Ignite has landed a mid-table end result right here, which is fairly first rate given it has been in the marketplace for round half a decade already.

14. Sweet Protection Tucker 2VI

We’re into the underside half of the desk now, however the Sweet Protection Tucker 2VI remains to be sooner than 11 different helmets on this check, which is not any imply feat. The Tucker is a fairly enclosed helmet with two small vents on the entrance. One dries out the forehead, whereas the opposite reduces strain on the centre-most level. There’s additionally a slot on the high to reap the benefits of the Venturi impact. It’s borne out of the Tucker time trial helmet, however with the visor eliminated and a slight redesign. 

It boasts MIPS’s properly inconspicuous Air Node system for added influence safety however the minuscule dial on the rear lets it down, as generally is a bit powerful to know, particularly when sporting gloves. 

Compared to the quickest on check, you may be gifting away simply shy of six watts at 40km/h, or deal with a 40km at 250 watts and you will lose round 25 seconds. That’s a not insignificant period of time, however nonetheless, a better hole separates the Tucker 2VI and the slowest on check. 

15. Kask Elemento

The helmet of alternative for most of the Ineos Grenadiers workforce, the Kask Elemento is the following period of helmet design, based on the model. A carbon fibre shell replaces conventional EPS foam, which implies it may possibly provide related ranges of influence safety with considerably much less bulk. Elsewhere, 3D-printed pads substitute conventional foam pads, and with their lattice-like development, the airflow inside is improved.

The Elemento is a really costly helmet, and there are just a few good causes to purchase it, however all-out aero pace is not its forte. A Kask spokesperson informed Cyclingnews that this is not a devoted aero helmet, as its rounded form suggests, and that it might land someplace between the aero Utopia Y and the ethereal Valegro. We did not check the Valegro, however the mid-table efficiency right here suggests Kask was proper. 

16. Limar Air Atlas

We’re undoubtedly getting extra into the realm of all-rounder helmets now, relatively than devoted aero lids, however the Air Atlas remains to be touted as a go-faster helmet by Limar, so the model is perhaps a bit of disheartened by our outcomes. 

This is the helmet you may discover atop the pinnacle of most of the Astana Qazaqstan riders, and as such, the person who kicked off aero helmets all these years in the past, Mark Cavendish (he wore a helmet with an aero shell to cowl the vents when successful the World Championships in 2011). 

With Cavendish in thoughts, for a little bit of enjoyable, I calculated a 200-metre dash – at a flat common of 1500 watts – within the POC Procen Air (with visor) in opposition to the Limar Air Atlas. With every thing else equal, by the point the Procen Air had accomplished the 200 metres, the Air Atlas can be 1.43 metres behind – a particular successful margin.

17. Abus Gamechanger 2.0

The very helmet utilized by Mathieu van der Poel, the Gamechanger 2.0 helmet is a particular aero-first helmet, so the outcomes right here had been a little bit of a shock. 

I’ve personally had an important expertise utilizing, racing and customarily proudly owning the unique Gamechanger helmet, and the two.0 seems to be an enchancment on that, however on this specific check, it did not carry out in addition to we would have thought, dropping round 6.6 watts in opposition to the Procen Air.

18. Oakley ARO7 w/out Visor

If you are worried about wanting foolish within the Procen Air – you and me each – then the Oakley ARO7 takes the prize. Carrying extra of a commuter helmet aesthetic, the ARO7 is chunky, and though that does add to the sense of safety, it sadly additionally provides to the drag coefficient.

Notably, in contrast to the Procen Air, this helmet is quicker with out the visor than with it, however in each guises, it is nonetheless firmly within the backside third of our desk, and would require precisely seven extra watts to carry 40km/h.

19. Carnac Evo

The Carnac Evo is our leftfield inclusion, as a result of in contrast to all the opposite helmets right here that value a not-insignificant sum of cash (the most cost effective being the Van Rysel at £89.99), this one value simply £19.99 plus transport. 

We included it as a result of we needed to see what the distinction between ‘low-cost’ and ‘costly’ are, and see whether or not spending a whole bunch of kilos/{dollars}/and so on is definitely crucial. 

The reply, sadly for these of us on a shoestring funds, is sure on a number of counts. Aerodynamically, it isn’t the slowest helmet on check, nevertheless it’s actually one in every of them. At low yaw angles, the Carnac Evo does rise up properly in opposition to the rivals, however as soon as the wind angle grew, its CdA rocketed. 

However, there are a few huge caveats to this studying. Firstly, anybody who’s been round for just a few years will see this the resemblance of the unique S-Works Evade helmet right here. I’m not right here to invest on how the design got here to search out its means right into a Carnac helmet, however the actuality is, Specialized is aware of tips on how to make an aero helmet, so that is maybe not the fairest illustration of your generic ‘low-cost’ helmet as a comparability to the costly fashions. 

The second caveat is that the standard of the helmet’s development feels according to the low price ticket. For instance, upon eradicating it from its field, a big piece of surplus EPS foam broke off in my fingers, and upon attempting it on, there have been two important strain factors between the highest of my head and the helmet. Of course, your mileage might range, however I might suggest attempting before you purchase. 

20. Specialized S-Works Prevail III

Another leftfield inclusion right here, the S-Works Prevail III is something however an ‘aero’ helmet by design, with big gaping vents up entrance. 

Why embody it then? We needed to get a really feel for the distinction between an ‘aero’ helmet and an ‘ethereal’ helmet, to see what positive aspects you get whenever you make such a swap. The reply, within the case of the S-Works Prevail III in opposition to the S-Works Evade III, is 24 seconds over 40km when using at 250 watts. 

Thinking of a sprinter, if the likes of Tim Merlier had been to decide on the Prevail as an alternative of the Evade, they’d be gifting away 1.22 metres in a 200-metre, 1500w dash. Things get a bit extra difficult when the temperatures climb, although, as a result of the Prevail is way cooler (temperature-wise; I’m not the most effective decide of trend) and a cooler core temperature might end in higher energy output, which offsets the aero acquire a number of occasions over. 

21. Rudy Project Nytron

We’re moving into the ultimate few now, and apparently, regardless of this gorgeous poor end result, Rudy Project says its Nytron helmet was developed in a wind tunnel with assist from aero consultants Swiss Side. It’s unclear precisely what enter Swiss Side had, nor what assessments had been used within the improvement, however I’m not one to doubt their credentials. 

Instead, let this be a reminder that our information is solely a mirrored image of our assessments – not the ultimate phrase on efficiency – however goals to supply an neutral stream of information in opposition to a backdrop of wider context, that may hopefully assist our readers. 

With that mentioned, at 40km/h, 7.24 watts separate the Nytron and the Procen Air, whereas a nonetheless important 5.51 watts separate it from the slowest on check. 

22. Oakley ARO7 w/ Visor

We’ve already touched on the ARO7 above, and right here we get the results of the identical helmet with the visor connected, scoring a mean CdA of 0.3607. The visor itself is sort of a sizeable factor, it curves laterally across the head, however would not actually curve within the vertical airplane, that means it offers fairly a big floor space to catch the wind and add drag to your experience. 

23. Uvex Rise Pro

Uvex is the helmet you may see atop the heads of the Intermarché-Wanty 2024 workforce. It’s very evidently an all-rounder helmet relatively than a devoted aero lid, however we selected to incorporate it as a result of we needed to incorporate as most of the WorldTour sponsors’ helmet choices as potential. 

Naturally, the likes of Biniam Girmay and co might be disheartened to see that – in our assessments – they’re gifting away round eight watts on the conventional racing speeds (40km/h) and extra because the speeds develop, however with 5 wins and a handful extra podiums beneath their belt to this point this season, it would not appear to be harming them an excessive amount of. 

24. POC Ventral Tempus

Interestingly, whereas the winner of this check is POC with the Procen Air (visor), the Swedish model additionally finds itself on the backside too, with the Ventral Tempus and the usual Ventral, beneath. 

Focussing on the Tempus for a second, the efficiency right here held a strong mid-table end result at decrease yaw angles, earlier than ballooning at a 15-degree wind angle. This is maybe as a result of unconventional strategy of merely taking an present helmet and including a canopy. 

It’s price saying that the Ventral Tempus is not firstly an aero helmet. It was created as a helmet for unhealthy climate in response to the UCI banning add-on helmet covers, which professional riders tended to do within the rain. 

The idea was that including the quilt additionally benefitted the aero efficiency, and whereas that is confirmed true, it isn’t by a lot, with a saving of two.6 watts. 

25. POC Ventral

It’ll be combined emotions for the Swedish model, POC, whose Procen Air helmet lands squarely on the high of this check, whereas the Ventral lands on the very reverse finish. 

There needs to be a loser although, and final, however not at all least, comes the model’s former flagship aero mannequin with a mean CdA of 0.3656. Although, it was by no means a die-hard aero helmet, and extra a refined model of the POC Ventral Air all-rounder. 

Looking on the graph, just like the Ventral Tempus, it held a fairly first rate efficiency on the decrease yaw angles, earlier than stepping up in a giant means at 10 levels. Interestingly it got here again into the realm of the rivals at 15 levels.

Interestingly, on the launch of the Procen Air, POC mentioned it saved 18 watts at “racing speeds,” which it positioned at 30 to 60km/h. We’ve received the CdA right here, so working the maths between the 2 helmets, you get a distinction of 5.38 watts on the comparatively sedate 30km/h, and an enormous distinction of 43 watts at 60km/h, with the caveat that at these speeds, the yaw angle can be constantly near zero, and the rider place would must be considerably extra aerodynamic than our relaxed, comparatively upright testing place. 

The conclusions

There we’ve it, 23 helmets, 25 assessments, and an entire heap of numbers for information nerds to feast upon, however what did we be taught?

1. You do not must be a professional to make financial savings

While we did the check at 40km/h, it is the ability differential at slower speeds that I feel stand out extra. Riding at 40km/h by yourself might be powerful. Not unfeasible for an beginner racer, however powerful. When you do experience that quick, you may most likely be using in a bunch, the place the aerodynamic significance is decreased by the discount in wind drive. While an aero helmet remains to be helpful, the real-world distinction might be smaller than in the event you had been in a time trial or a solo breakaway.

However, most eager amateurs will be capable to maintain 30km/h for prolonged durations of time, and the distinction on provide right here at that pace is round 5.4 watts. For somebody with a 270-watt FTP, that is a 2% bump in efficiency just by swapping helmet. That’s important, and a saving that almost all amateurs will be capable to get. 

With that mentioned, a professional rider in a breakaway at 50km/h stands to avoid wasting practically 25 watts between the POC Ventral and the POC Procen Air. The one caveat right here is that we’re utilizing CdA information pulled from a relaxed using place relatively than an aero-hoods breakaway place, so it isn’t completely transferable, however POC-sponsored EF riders ought to nonetheless take word.

2. Helmets save greater than wheels

Some of you may recall that we went to a wind tunnel again in 2022 to check mid-depth street wheels. The winner of that check was the DT Swiss ARC 1100 Dicut, at 62mm deep. Compared to the slowest on check, they’d prevent 3.87 watts at 40km/h. Those wheels are within the area of £2,300, whereas the 2nd place Hunt Limitless 60 wheels had been 1.9 watts slower and round half the value. 

Of course, in the event you put your cash into some new wheels, there is perhaps different advantages like weight, and improved tyre interplay which might result in improved grip and rolling resistance. Alternatively, you could possibly spend lower than 10% of that money on a helmet and get considerably better aerodynamic positive aspects. Who’s saying you’ll be able to’t do each?!

As all the time, the positive aspects on the desk are completely depending on what you are beginning with, so widespread sense shall prevail. 

3. Aero design is not all the time aero

On visible inspection, evaluating the Rudy Project Nytron with the Specialized Prevail, and everybody would assume the Nytron is the sooner helmet. It has a closed-off entrance with simply a few vents, whereas the Prevail is arguably extra vent than helmet, however the outcomes communicate for themselves. It’s a notable development all through our outcomes. The all-rounder Giro Eclipse eclipsed (pun very a lot meant) devoted aero lids just like the Sweet Protection Tucker, and the Trek Velocis was solely a fraction slower than its aero stablemate the Ballista. 

I feel on the steadiness of averages, the aero design does win out general, however do not assume that simply because it appears to be like aero, it really is. 

4. Sort out your straps

On researching for this text, I met with a helmet designer who spoke in regards to the aerodynamic and security penalty of unfastened helmet straps. You might spend hours toiling over selecting which helmet to purchase, solely to undo all of the positive aspects by having a strap that flaps within the wind. From a security standpoint a correctly fitted strap is smart, even in the event you do not care about aero positive aspects. 

5. Don’t negate match

The final takeaway is extra of a PSA than a studying, per se, however an necessary one nonetheless. You are shopping for a helmet as a result of sporting one is safer than not sporting one, and an ill-fitting helmet is not protected. 

If a helmet saves you six watts, however would not do its main job of defending you in a crash, these six watts may shortly appear extremely trivial, so whenever you’re shopping for a helmet, be at liberty to make use of these numbers as a information, however not as gospel. If a helmet would not match, feels a bit wobbly, or blocks your imaginative and prescient, strive one other one which does.