Like this site? Help us to make it better.


Bell Star Pro helmet



Comfortable aero helmet with adjustable air vents attempts to offer best of both worlds, but ventilation is lacking

At 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 scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

The Star Pro is Bell's brand new aero helmet and what sets it apart from most aero helmets is a slider that opens and closes the side and top vents. With the vents closed, Bell reckon the Star Pro is faster than the fastest aero helmets currently available, while with the vents open, they claim ventilation as good as any regular helmet.

Aero performance

For this new helmet Bell developed what it calls Active-Aero Technology. Quite simply, there's a plastic slider at the back of the helmet that can move an internal liner to open or close the top and side vents. The rear vents remain open at all times.

When you want maximum aerodynamics you close the vents, when you need some refreshing air over your scalp, simply open them up. It's a simple concept, and well executed. The Kask Infinity has a similar sliding vent but that's at the front.

The slider functions well, and is easy to do on the move WITH just one hand. It doesn't have the premium feel you'd expect of a helmet costing £200 in its most expensive incarnation however, instead it feels a bit cheap and plasticky. I'd expect better at this price.

In its own testing at the Faster wind tunnel in Arizona, USA, Bell reckons the Star Pro with vents closed is faster than any of its competitors such as the Giro Air Attack and Specialized Evade. With the vents open, the company claims it's as effective at keeping your head cool as a traditional road helmet.

"A full range of competing aero helmets were tested at the Faster wind tunnel facility [in Scottsdale, Arizona, USA] utilising the industry-adopted wind-averaged drag (WAD), a wind velocity of 25mph (40kph), and a 30° head angle for all helmets," says Bell. "Tests proved that the Star Pro, with vents closed, is the fastest helmet on the market when compared to other very well-known aero competitors."

These are impressive claims. They're also claims that, along with most aero products, are impossible to verify without access to a wind tunnel. One day the industry might develop a standardised testing protocol for aero products but until that day happens, you can only take the company's claims at face value.

I did attempt to gather some comparative data against several regular vented helmets using a PowerTap to monitor the power requirements at different speeds, but wasn't able to get any meaningful results, which demonstrates how marginal the gains are with such a product.

If you want even more aero, the Star Pro can be bought with an optional visor (£30) that clips into place with a magnet, offering an extra aero advantage to those seeking every performance gain they can spend their money on.

I ditched it after one ride; it might be fine for racing but I didn't half feel a tit on a spin around the lanes. Let's just remember that this helmet has been designed for racing; it was developed in partnership with the Belkin team, so it's really aimed at those wanting the highest performance product.

A bit hot in here

What the Star Pro helmet does prove is that providing an aero helmet with adequate ventilation is a tricky compromise, despite Bell's best efforts to offer the best of both worlds.

There are vents underneath the front of the helmet, dubbed 'Overbrow Ventilation' which in combination with the side and top vents when the slider is open, does provide reasonablE cooling. It's nothing like the ventilation a Specialized Prevail or POC Octal provides though, but it's not bad. Even during this unseasonably warm weather, I never experienced an uncomfortable increase in temperature when riding around with the vents open.

With the vents closed, and if you're racing you'll be wanting to make the most of the aero benefits, it's another story. Those small 'Overbrow' vents simply don't provide enough airflow and my sweat rate increased massively, and it has nowhere to go but all over your face.

Even before half distance on a brisk one hour ride the other day, I was dealing with such an excessive amount of sweat pouring down from my brow into my face that I was ready to just ditch the helmet right there. There's simply inadequate venting that on a remotely warm day, you're going to struggle to prevent the extreme buildup of sweat.

You can partially combat this by leaving the vents open all of the time, but then you're compromising the aerodynamics, and thus defeating the point of buying an aero road helmet. Once you've reached the point of becoming a sweaty mess, opening the vents is too little too late.

Good fit and comfort

What of the rest of the helmet? Well it's a comfortable place to put your head for a ride, with the size medium fitting my head very well. There's a good range of adjustment and the retention system, though sitting a little high, is easy to operate and clasps the head with just the right degree of pressure. There is a good smattering of soft pads inside as well.

The helmet is constructed from a two-layer EPS, with lower density foam in the interior and high density EPS foam for the outer layer. The Star Pro will be available in three sizes and is CPSC and CE EN1078 certified, and there is a choice of six colours.


I was ready to love the Star Pro helmet. As it is, wearing it in warm to hot temperatures is just asking to become a horrible sweaty mess. Given most people looking to buy an aero helmet are probably racers, and most races are in the summer, that does limit its usefulness quite a bit.

It just goes to show you can't have an aero helmet without sacrificing decent ventilation. The rising popularity of aero helmets does show that this is a compromise many are happy to make, but for most people the potential gains are so small that you're probably better off sticking with a well ventilated helmet.


Comfortable aero helmet with adjustable air vents attempts to offer best of both worlds, but ventilation is lacking

If you're thinking of buying this product using a cashback deal why not use the Top Cashback page and get some top cashback while helping to support your favourite independent cycling website test report

Make and model: Bell Star Pro helmet

Size tested: 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?

Star Pro is equipped with first-of-its-kind Active-Aero™ Technology, which gives cyclists the ability to regulate airflow, temperature and aero efficiency on the fly with a simple slider mechanism that opens or closes its vents. This ensures riders are able to adapt to situations and gain optimal performance benefits throughout the course of a race. The Star Pro and its Active-Aero™ Technology was developed to address a long-standing gap in the market where riders previously had to sacrifice one for the other when it came to aerodynamics and ventilation. While other manufacturers may promise the same, never before has a cyclist been able to control the ventilation or aerodynamic capabilities with a simple flip of a switch in the middle of a race.

Extensive research and testing was conducted on the Star Pro to validate its abilities and to back up its performance claims. A full range of competing aero helmets were tested at the FASTER wind tunnel facility utilizing the industry-adopted wind-averaged drag (WAD), a wind velocity of 25 mph (40 kph), and a 30-degree head angle for all helmets. Tests proved that the Star Pro, with vents closed, is the fastest helmet on the market when compared to other very well-known aero competitors. And when measuring the Star Pro's cooling efficiency, with vents open, it proved to be near equal to a traditional road helmet over a 30-minute period, but more importantly, cooled faster than a bare head during the initial five-minute period giving the cyclist the ability to cool their head mid-ride.

Beyond its Active-Aero™ Technology, the Star Pro is packed with innovative design features, providing riders with Overbrow Ventilation, multi-density Progressive Layering, and a Magnetic Zeiss Shield for integrated eyewear on select models. Overbrow Ventilation regulates temperature by drawing cool air into the intake ports and circulating it through a matrix of air channels that push out warm air through the exhaust ports. The Progressive Layering includes a two-layer liner that has softer density EPS foam on interior sections and stiffer EPS foam on exterior zones. A Magnetic Zeiss Shield provides optimal protection and visibility, but removes and stores easily on the helmet exterior when not in use. Additionally, the Star Pro will come with an all-new Float Fit System that has optimal adjustment to ensure it sits comfortably on the head.

Tell us some more about the technical aspects of the product?


Gives you the ability to regulate airflow, temperature and aero efficiency on the fly with a simple slider mechanism


Regulates temperature by drawing cool air into the intake ports and circulating it through a matrix of air channels pushing out warm air through the exhaust ports


Two-layer liner has softer density EPS foam on interior sections and stiffer EPS foam on exterior zones


Integrated eyewear for optimal protection and visibility; removes and stores easily on helmet when not in use

Rate the product for quality of construction:

Well constructed generally but the slider operating the vent is seriously lacking a premium feel you'd expect of a £200 product.

Rate the product for performance:

Fast if you believe the aero claims, but lacking in ventilation does limit its practical usefulness.

Rate the product for weight, if applicable:

It's not particularly heavy, nor is it particularly light.

Rate the product for comfort, if applicable:

No problems with comfort on the head, a nice fit with good adjustment. The retention system does sit a bit high at the back of the head though.

Rate the product for value:

A tricky one this, some will be sold on the aero benefits but unless you're looking for every performance gain you can lay your hands on, there are better ventilated helmets that are more practical in the real world.

Tell us how the product performed overall when used for its designed purpose

Doesn't quite live up to Bell's claims to offer the best of both worlds, ventilation is seriously compromised.

Tell us what you particularly liked about the product

The potential aero gains.

Tell us what you particularly disliked about the product

Looks like a bowling ball; very sweaty on hot and fast rides.

Did you enjoy using the product? Not when it got sweaty.

Would you consider buying the product? No.

Would you recommend the product to a friend? Probably not.

Anything further to say about the product in conclusion?

Unless you're seeking every performance percentage increase, there's too little to be gained for the serious lack of ventilation provided by this helmet.

Overall rating: 6/10

About the tester

Age: 31  Height: 180  Weight: 67

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,


David worked on the tech team from 2012-2020. Previously he was editor of and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

Latest Comments