Which is best - aerodynamic or lightweight? The debate over which offers the greatest advantages for cyclists and triathletes continues to rumble on, so we've asked former pro triathlete and Team PF&H captain Brad Williams to give us the lowdown on this divisive topic...

In recent years, the discussion has been easily solved due to the vast amount of studies and research looking into the relative benefits of aerodynamics and weight. Additionally, easy-to-use modelling software, such as Best Bike Split, have become available, and this helps answer any questions you might have when it comes to what's more important for you on race day.

What are rider weight variables?

When we look at weight, there are two different variables that we're looking at:

1. The rider 

2. The rider's equipment.

For many people, the easiest place to save weight is by cutting out a few extra pastries throughout the week, or skipping a few pints...

Some athletes have already reached what they perceive to be their 'optimal weight' and the only place where they can save weight is through their equipment.

In fact, there are people who obsess with their equipment weight - these obsessed riders are known in the cycling world as 'weight weenies'.

They closely analyse every item they put on their bike, ensuring it's the lightest part available in order to make sure they've got the lightest setup that they could possibly have.

But is this 'nit-picking' really the best way of going as fast as you possibly can

Probably not...

Swiss Side’s Jean-Paul Ballard told road.cc, “In general, I say that in more than 90% of cases (rides), you would choose the aero setup.”

But why is that?

When it comes to aerodynamics, the rider makes up 70 to 80 percent of the drag, and the bike/equipment make up the other 20 to 30 percent.

For most people, they will find more gains focusing on their aerodynamics and reducing their CdA (coefficient of drag), rather than focusing on weight.

The exception?

According to Swiss Side, for an average rider, weight gains will mean bigger time savings than aero ones if the ride has an average gradient of 4.5% or more.

So if you're focusing on a race that has an extreme amount of climbing, or you're doing a hill climb, you definitely want to pay attention to your equipment choices when it comes to those rides.

If you have the luxury of multiple road bikes, these hillier rides would be the rare occasions where you should favour your super light road frame over the aero frame.

Image Credit: Finisherpix via Brad Williams ©

Additionally, maybe leave the flat kit at home and aim to carry the bare minimum - anything in the name of saving weight when you’re trying to set a PB and find that top step on the podium.

When should you focus on aerodynamics?

As a triathlete, I very rarely worry about weight.

Weight was a big topic of discussion in the summer of 2019 when the 70.3 World Championships course went up a mountain and then back down again. We discussed the course and potential equipment decisions just before the race, and even on a course like that, being aerodynamic still trumped being worried about weight, according to the models that we ran on Best Bike Split.

Furthermore, Team PF&H athlete Allan Hovda found himself in an interesting position at the end of 2018. He was without a bike sponsor and lacked equipment sponsors. He decided to make his best effort to become as aerodynamic as possible, under a project he's named 'Faster Than Superman'.

To accomplish this, Allan left no stone unturned and headed to the Boardman Performance Centre to utilise their wind tunnel. Whilst there he was able to confirm which equipment choices were optimal for him (i.e. helmet, wheels, kit, shoes, position, etc.).

Once he left the wind tunnel, Allan started making use of STAC Zero virtual wind tunnel to continue to refine his position and equipment choices.

On top of all of that, he is now dialling in all of the “little” things by having custom parts made for his cockpit with a 3D printer. Needless to say, Allan has taken his project, 'Faster Than Superman' to extremes in order to make gains, but Allan is just one example of someone who's paying very close attention to the details when it comes to aerodynamics.

Tools to help you improve aerodynamics

So now that we’ve convinced you that aerodynamics are more important than weight (most of the time), what can you do to ensure you're making smart choices? There are a few tools that I typically recommend to athletes who are looking to improve:

Aero Assistant (via AeroWeenie.com): A really simple starting place which will help you understand what the most affordable investments will be in order to get the most 'bang for your buck' when it comes to aero upgrades.

Best Bike Split: Packed with features to help athletes make the best decisions when it comes to not only equipment choices, but also pacing plans and knowing how hard (or easy) to ride certain sections of races.

AeroAnalysis.org: Quite advanced, but a web-based platform to use to analyse segment runs to see what gains (or losses) have been made with different setups.

AeroCamp (A2 Wind Tunnel): If you have the financial resources to make a trip to the wind tunnel, I highly recommend doing so with Brian Stover & Heath Dotson of AeroCamp.

They mainly utilise the A2 Wind Tunnel in North Carolina, but they have amassed a lot of data and knowledge on how to optimise and help make athletes faster.

I haven't been to the Silverstone Sports Engineering Hub and their wind tunnel, but if you're UK-based that's another potential option.

The wind tunnel is typically the most expensive investment when it comes to getting faster, but more often than not it's where you'll find some of the biggest gains as you optimise your equipment choices to you and your setup.

So, next time you’re contemplating which water bottle cage to purchase based on weight, maybe consider taking your money and investing in a more aerodynamic helmet or tighter fitting cycling kit/suit. Because, as Jean-Paul Ballard said, “in more than 90% of cases (rides), you would choose the aero setup.”

Further reading