Back in 2012, Specialized and McLaren announced a new helmet that they had developed together, and that was supposed to offer revolutionary aerodynamics. This product featured a short tail design that had been extensively tested in the wind tunnel. Most people tend to move their head around while riding, and this type of design offered a significant advantage over long tail aero helmets like the Specialized TT2 that would add a large amount of drag if the tail stuck up into the wind. The McLaren TT helmet was one of the most sought after products, but most people had immense trouble purchasing it. The helmet was produced in very limited quantities, and not sold through most of Specialized's retailers. Those who somehow managed to get a hold of that helmet also had to deal with certification issues. That helmet was not certified for use in CPSC competitions (almost all USA-based cycling and triathlon events), which was a no-go for many triathletes.
The S-Works TT is Snell B-90 certified, and also complies with US CPSC safety standards
This year, however, Specialized has released a new version of that helmet called the S-Works TT. This helmet features the same aerodynamic design as the original McLaren TT helmet, but is readily available throughout Specialized's distribution channels, and is also Snell / CPSC certified allowing it to be used in a variety of competitions. They have also added several new features that will appeal to a broader audience, including the option to use an integrated visor. At TriRig, we are huge fans of visors, so we were very happy to see this included with the helmet. The S-Works TT appears to be a very polished consumer-ready product, so let's take a look at it in further detail.
S-Works TT shape from above
As mentioned in the first paragraph of this article, the helmet features a truncated tail design, which has recently become popular among helmet manufacturers and consumers. When aero helmets first hit the scene, almost all of them had extremely long tails, which worked quite well if you stayed in one position with the tail out of the wind. What engineers discovered, however, is that few riders actually ride that way. For a very small percentage of people--those that keep their head in the optimum position and rarely move it--the long tail designs still usually make the most sense. But for the average triathlete, the short tail design is likely to be a better fit. These helmets truncate the tail about 2/3 of the way back. When you move your head up, down, or side to side, less of the tail sticks out into the wind, resulting in better aerodynamics. Truncated airfoils have already been commonplace on bike frames for many years, and the same aerodynamic principles hold true with helmet design. In many situations, you can get almost all of the benefit of a long airfoil, even if you remove a section from the back of it. The truncated tail of the helmet also allows for the tail to functions as a giant exhaust port for air to flow through the helmet and around your head. This helps with cooling, and is something we will discuss later on in the article.
The S-Works TT is very smooth, and presents as little frontal area to the wind as possible
The next thing you will notice about the helmet is that its frontal area is very minimal. In general, the smaller the helmet, the better it will perform. The sizes of this helmet (which we will detail later) have some overlap, and if you can use 2 different sizes, you will most likely get better aerodynamics from the smaller size.
The helmet is very smooth with no dimples (unlike the Louis Garneau P-09), and no vents on the top of the helmet. This ensures smooth uninterrupted air flow that won't pool up in air vents. There are "gills" on both earflaps that help direct air into the helmet, and channel it out of the exhaust port in the rear. Specialized claims that these gills actually reduce drag, and that covering them up reduces the performance of the helmet. The gills look miniscule, and I was worried that cooling would be terrible. I was pleasantly surprised, however, with how well they worked. I found the helmet to run cooler than most other aero helmets I have used. It is still hotter than a typical road helmet, but not much more. The gills do generate a bit of wind noise as wind speed picks up, and it can be hard to hear what others around you are saying during group rides. If you want to ride and chat, another helmet might be a better choice. But for triathlons and time trials, this is most likely a non-issue.
The "Gills" on the side of the helmet help with cooling, and actually reduce drag.
The ear flaps are semi-rigid, but pull apart a bit to make donning the helmet easier. It is not the easiest helmet to get into, but I found it to be acceptable. It is definitely easier to don than the Scott Split. I have had some trouble removing the S-Works TT, and haven't yet found an easy way to get it off. Sometimes I remove it without issue, sometimes I pinch my ears quite a bit, and sometimes I knock the visor off.
The biggest question most triathletes will have is what does this aerodynamic design add up to in terms of time savings? Specialized claims that the S-Works TT can save 62 seconds over 40km compared to a standard road helmet. If we extrapolate to ironman distance, that would be a savings of 279 seconds (4min 39 sec) over 180km, which is HUGE. This alone is almost enough to convince me to ditch my road helmet. While we haven't had a chance to test these claims, we don't have any reason to suspect them to be false. The helmet's aerodynamic design seems solid, and several pros that have experience testing it in the tunnel have said it lives up to their expectations.