Marginal Gains – Helmets

One of the most popular speed oriented purchases, though often hotly debated. Helmets rank very high on the speed per dollar (or currency of your choice) scale. However, what is not always appreciated is that the fastest helmet varies by individual.

Recent years have seen the price of new aero helmets skyrocket (as with many other cycling products), partially thanks to brands wanting to establish a ‘halo’ product and partly because the nature of the market has dictated a lot more R&D. For a brand that previously created helmets based on aesthetics it is an expensive proposition to recover the cost of CFD and wind tunnel testing. Additionally the last couple of years have seen the advent of aero focussed road helmets which are a useful new option on the market.

Time Trial Helmets

Giro Advantage 2 - bad for my but generally pretty good
Giro Advantage 2 – bad for me but generally pretty good

One of my first posts when I started this site was about a trip to the Canterbury University Wind tunnel. During that testing I discovered that the Giro Advantage was 0.8s per km slower than An LG Rocket for me. And yet the Advantage is one of the most reliable aero helmets around – by which I mean that is usually one of the better options for most riders. But not for me. A later test of the Giro Selector was similarly disastrous for me (disastrous as I’d been racing in it and slowing myself down unintentionally).

I’m not about to share the info from testing my clients but suffice to say – the variation between helmets that I’ve indicated for myself is not uncommon.  It’s almost hard to credit how individual the selection of an optimum helmet is.

So when you see marketing claims along the lines of “our new helmet is x% faster than the best of the competition” – ignore it. It means nothing to you. Unless you have the opportunity to formally test helmets you’re just guessing. As a general piece of advice I’d recommend not buying a TT helmet costing more than NZ$400 (unless you have the opportunity to test first) – I’ve rarely seen a client have the best results with one of the really expensive options.

Given the individual nature of performance gains it’s not possible to give precise data on the benefit of aero helmets. As a general guideline I normally work with ~1min per 40km. For some riders the gains will be significantly more. Further – an aero helmet offers roughly the same benefit as a set of deep (60mm or more) carbon wheels (vs training wheels) at 5%-10% of the cost so helmets are clearly a cost effective way of gaining speed.

Kask Bambino - not a helmet I recommend unless you can test before buying
Kask Bambino – not a helmet I recommend unless you can test before buying

There has been a trend over the last few years towards snub tailed TT helmets – Kask and Casco notable contenders in this market. If you are a triathlete I’d be very cautious about purchasing a helmet of this style – they tend to work well for those who can adopt a position with their head down in front of their torso. If your head is sticking up above your back it is likely that you will gain more benefit from a longer tail to smooth the airflow off your head (but as above – this is a gross generalisation and a snub helmet may actually be fastest for you as an individual even if your head is sticking up).

If you want a compact helmet for Triathlon you’re probably best to focus on the next section.

My general advice for TT helmets is to get one that is comfortable and you like the look of and then don’t worry about it unless you get a chance to test other options properly. The Giro Advantage (my results notwithstanding) is a good first port of call – not too expensive, well proven, comes in 3 sizes and is usually pretty quick. Bell offer the Javelin if you like the idea of a visor. I’ve had extremely good results with the LG P-09 for a number of athletes in recent testing and that is probably the helmet I’d recommend if you’re looking for latest tech.



Aero Road Helmets

LG Course - my preferred aero road helmet currently
LG Course – my preferred aero road helmet currently

Giro rather reinvented the high end road helmet market with the introduction of the Air Attack – a premium priced stack hat similar to what you had as a kid in the 90s (if you were a kid in the 90s). The dubious aesthetic appeal did not deter a horde of riders from taking advantage of the (now well proven) aerodynamic benefit.

Fortunately for those with delicate sartorial sensibilities there are other options – the LG Course and just released Giro Synthe (not available in NZ yet) look much like a normal helmet. The Specialized Evade sits partway between those two and the Air Attack for visual (lack of) appeal. All are fast helmets and I find the Course and Air Attack to be very comfortable.

Giro Synthe - not in NZ yet but will be a good option
Giro Synthe – not in NZ yet but will be a good option

For a road cyclist these helmets offer a real benefit in a racing situation – no weight penalty, better aero, equal comfort (in my experience). Obviously a draft legal triathlete would gain the same advantages.

For a long distance triathlete aero road helmets offer a nice balance. Not quite as aero (for most people) as a full on TT helmet but much lighter (which can aid neck comfort), better ventilated and generally more comfortable (ears aren’t squeezed). If you object to the looks of a long tailed helmet the innocuous speed of an aero road helmet is a real boon. Over the coming years I expect aero road helmets to outnumber TT helmets at hot Ironman races.



Aero helmets are one of the few things that no one really argues aren’t worth it – the performance advantages are easily (and fairly universally) proven. Of course, which particular model is best is hotly debated – but that is a pointless discussion. My advice is that you should definitely race with an aero oriented helmet and choose based on looks/price unless you have access to demo helmets and accurate testing.


Reflecting the importance of helmets I actually have quite a few in stock, apart from the ones for use in testing. As with any aspect of performance I make sure I can source the best products for my clients.







Synthe is claimed weight, all others I weighed the medium. Specialized Evade 278g for a size small and I believe they’re $399 – you would have to talk to a member of the Empire for more details.

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