Really appreciate the wind tunnel series, Alex. Thank you. In regards to the TT5, here's a hypothesis: 1) the airflow at the rear helmet/shoulder interface is improved by using the entire interior of the helmet to funnel a larger volume of air out the rear channel; and 2) the helmet/rider system is better optimized by doing things like closing down the gap between the head and hands, as others have mentioned. As you point out, the Tempor and the Redeemer use vents and ducts to guide airflow over the shoulders. My guess is the volume of air coming through the rear channel of the TT5 is significantly greater than the volume going through the relatively smaller channels of the Tempor/Redeemer. If Specialized is using the helmet interior as a flow channel, it gives insight into design features like that damn sock and the pointy parts on the side of the helmet below the visor. The sock eliminates hair as a flow restrictor and the pointy sides act as guides to increase flow. Combined, both of these features increase flow through that rear channel, which improves flow attachment across the rider's back. I suspect too that the effectiveness of the TT5 rear channel diminishes at higher yaw angles, simply because of less flow through the helmet, which would explain why the performance advantage of the TT5 relative to the Tempor/Redeemer goes away at higher yaw angles.

15:50 The visor is set so far away from the face to close the gap between the head and the hands, you can see it beautifully in 13:30

Alex the helmet box rule already exists.

favorite part of this series: "Big gains"

Thank you Alex!!! Much appreciated

Alex, thank you for such great content!

Test the new helmets anyway CTT and triathlon riders could still use them if the UCI ban them

Kask flap is most likely a trip line. Makes flow turbulent instantly. Turbulent flow has less pressure drag and more skin drag. The opposite is tru for laminar flow. Generally pressure drag is the main component of your total drag. So taking an increase in skin drag would be ok if you decrease the pressure drag considerably.

Please test the POC Tempur with and without the front vents taped up. Thanks!

Loving the series!

👏👏👏Everything you said, about the fia, the uci, everything! Couldn´t have said it better myself!

Great video Alex, I have been enjoying the content. Me and probably 50% of all triathletes are looking to see how the Aerohead compares to all the other helmets. Thanks

Very interesting information. I would love to throw on that POC for a gravel race and let people gawk 🤣. In all seriousness will definitely be taking this information and applying it to my road and gravel setups as much as I can. Great series Alex!

it would be interesting to see the difference on the helmets that have the laminar air flow, if the rear "holes" were plugged...basically testing the effectiveness of the airflow.

The Specialized helmet looks like it is considerably taller than the others and directs the air above your back rather than along it. Maybe the cutout creates a trip or pressure difference that somehow benefits the airflow over the back.

Attila Valter's position suited the Giro 2 near perfectly, looked one of the best under/behind it

Thanks for this Alex. Would be interesting to hear your thoughts on the mistral vs the bambino pro evo and if you tested them?

with every new video on aero helmets I get more unsure about which one to pick 😂 will do my first real aero tests with aerotune this year and see... thx Alex 👍 (if I win the lottery before, I'll fly over to SIlverstone instead)

I couldn't give a tinkers cuss about how fast I cycle; like many (most?) cyclists, I think. But this and all your wind tunnel videos are fascinating! I guess it is because it is always entertaining to watch an absolute expert, enthusiast and good communicator talk/demonstrate his/her passion. Plus one with world leading credentials .... I strongly suspect that Chanel, 8.9999 months pregnant, crabby as hell, and wanting to be anywhere else would be faster than me (not prettier, though)

with the tt5 helm all of the odd lines and things line up very well when you have your head tucked into the bike especially with the flat back it is directly inline with your back, and the visor looks like a bubble of nonmoving air so aat speed the wash just flows over that part and to the next piece of drag. *just saw the included clips and maybe i'm wrong?

Good job

Looking at the TT5 at 13:29 in the video, I wonder if it works so good because the visor hangs down much longer and its not the back of the helmet that makes it fastest? The visor covers your whole face at that angle and might help fill in the gap kinda how triathletes now are putting a water bottle down the jersey.

The sweetspot doesn't actually look so bad in black. It's made worse by the Uno-X colour scheme.

thanks Alex - I was debating getting the POC Tempor - I'm a wider person and you convinced me to save my hard earned dollar.

It's a pleasure to watch your videos! They are priceless! But I'm not completely agree with the comparison between the UCI and the F1. F1 doesn't make or influence everyday car, they have little to no implication to even the raciest open road car, but UCI did (in some sense). It's true UCI from time to time seems to ban things that are "futuristic" or too much "forward thinking", but in a whole it's probably the only reason why we commoner's are still riding bike almost identical to the pros. if UCI were like F1, just within years the pros will all be racing recumbent bikes with wind shields like a torpedo lying down because that is the most aerodynamic position. With pro's power we could expect to see the race speed jumping to 60K or even 80K (I don't really know that, how fast will a torpedo recumbent bike go, in a peleton, with drafting, averaging 300+ watts...). That's the F1 form of bike. It's just lucky that we have UCI that we haven't come to that. In my oppinion the F1 is not a good example. How related can you feel with an F1 car??? When the distance is so great people will just walk away and don't care about it anymore. That's the problem of motor sport like F1, it doesn't relate to what you can drive anymore. Most people would rather watch cars like an AMG or M3 because that's much more real. Luckily today we are still riding the technically same bicycle that you guys pros riding. I think UCI is protect this sport in the terms of "accesibility". The aesthetic is actually part of that accessibility problem. If something looks too wierd -> people won't try as easy -> hard to access (more mental commitment needed, more social barrier). It did protects the "integrity of the sport".

Thanks for sharing this stuff. The small exit deltoid reflector on the POC (i think) would result in higher airflow velocity, the pressure will be lower (not higher) according to Bernoulli anyway. That would suck air in, like Dyson fan, so probably that’s what makes the air stick.

4 mins: the parallel is more with types of rally car racing and touring car track racing, not Formula 1 - hence products have to be on sale to the public, even if only extremely wealthy members of the public. And Rally car racing is closer to normal world in genral than F1. That would also help marketing and sales so, if you can afford it, you can ride & wear just what the elite pros ride and wear. No matter how wealthy you are, you can't own or drive an F1 car so no market there.

The TT-5 worked for me as good as the tempor. Could be you change a bit on the cockpit and results are totally different. It's testing with open end i fear ...

After looking at these helmets and the recent UCI announcement I am predicting the upcoming the ban/regulations will have something to do with visors. Some of these visors are really absurd for being part of a safety device.

The sock ban is silly. Maybe there will be a bunch of riders with a balaclava on just to stay warm suddenly.

I'd be curious to know how good the tt5 is on different people with and without the snood

If there are slots that make air flow through the helmet shell and over the rider's head, does it matter if rider has spikey hair, bald, lots of smooth lying hair?

15:27 The flaps are there to create a downward force on the rider's head, just so that they are forced into their head down aero position to maximise gainz. #aero #FasterThanThe2024Alpine

The Spesh TT5 is definitely black magic. It looks like a bucket. Head on, in your comparison with the SP, the TT5 doesn't like it's making any attempt to smooth the airflow around the shoulders. How does that bucket manage to be so good?!!

Lamina flow, flaps, helmets, I though I was watching a video about cycling 😉

I wish the UCI made a standard template that gave all riders an affordable, easy to see out of, comfortable, helmet where aero was just standard for all riders

Hey Alex. Im curious to get your thoughts on how to make the current TT5 helmet UCI compliant for all of the individuals (like myself) that already have the helmet with sock. Is it a matter of simply not using the sock in UCI races? (maybe finding a way to pin it to the top to keep it out of the way) I know some modification of products is UCI illegal, so maybe Specialized could authorize the removal of the sock? Im sure you have far more experience with UCI, how strict they are with the rules, and reading the fine print on bans and rules, so I'm curious to get your opinion. Id like to not have a several hundred $ paper weight for nationals...

You have to ask when doe's a helmet become a fairing. Its the same with additions to frames and no actual functional use but simply aero.

They would all make so much difference on the A14/A11 course with all that traffic 🤷🏼‍♂️

Just want to understand, so the difference is 2% on total drag / watts as opposed to 2% difference in the saving of the watts if you know what i mean!!? Secondly do you think any of these have enough ventilation for an Ironman? Love the content 🙏🏽

Hi Alex, any reason why you go with the POC without visor? Have you tested with and without? Coukd you also comment about the use of a magnet in tail which you shared a while back?

With no ventilation how's the heat

Is the data associated with this testing available/posted anywhere? It would be interesting to see how some of the other, older helmets (like original Aerohead) compare to these top 5 - and how much slower are they?

❤❤❤

I'd like to see the riders visibility from inside the giro helmet

was there a reason for the poc to not have the visor?

"it also has to be an item they look at and can sell a lot of" When you see the latest frames used by the national teams (like the hb.t or the speedmax track) being obtusely overpriced at £25k, or even just the stupid practice continental had of making people phone up through hard to find contacts to buy a pro ltd tub years ago, I think plenty of manufacturers just pay lip service to that rule.

Waiting thé results of HJC helmet

very curious how much of a difference TT5 has with/without the sock

"I wish it was longer" Make it longer, tape and cardboard would be cool to see.

Is it just the sock that has been banned, or the entire helmet?

dont you overheat in those helmets and therefore lose more watts due to your body autoregulating your poweroutput to a lower leven than gain from being aero?

Can the specialized sock be removed for washing?

not really (on issue that all product have to appeal to the popular market as well) - how many Lotus bikes are there in the wild? :)) So "in theory" all products have to available for consumers - but that is BS. You are spot on on accountability of UCI (or rather lack of) on how the rules are put in place, followed and executed (in races, for elite and masters racers alike)

This is old mate that designed the Sweet Protection www.youtube.com/@KYLEENGINEERS

Why can you have a fairing on your head, but not have fairings on the fork or head tube, yet aero bikes are okay. The UCI is so fickle.

The definition of a helmet is a device for protection. UCI could just ban all helmets with any other focus then protection. Another possibility could be a UCI one person committee with a none cyclist that should rate: goofy or not Goofy will pass and be legal

Don't think I'd call Vernon narrow tbh. I'm ~35 cm biacromial width at 180 cm but unfortunately with long legs. There was a longer version of the sweet protection during prototyping . Why did they go with this design, who knows?

The box rules helps small cyclists. Thats also why we shouldnt change the bike weight limit.

I would ban all the competition-by-engineering stuff, other than in reliability. I'd have the riders on regulation bikes - metal tubular frames to very strict constraints. I would allow engineering competition for components that wear or fatigue -bearings, chains, tyres, the frame construction, etc. And I would then require that those components are fixed at the start of a race. It has to last. If it breaks due to wear/fatigue failure, tough luck - you can't change it, if that means you're out you're out. I'd probably do similar for clothing. Cyclist are dripping in oil when it comes to their clothes, completely unsustainable and daft. I'd have them back in wool jerseys. ;)

The collaborative effort evident in this video-from scripting to editing-is praiseworthy. It's a testament to the power of teamwork in creative endeavors