You are probably chasing aero in the wrong order. While you fret over tyre pressure and the latest deep-section wheels, Alex Dowsett — former UCI Hour Record holder — was in the wind tunnel helping Mark Cavendish find the gains that actually mattered. And what mattered was rarely the expensive stuff. Dowsett walked through the whole approach on Dowsett's Aero Masterclass At Astana on the Roadman Cycling Podcast, and the lesson for amateurs is uncomfortable: most of your free speed is sitting in your position, not your kit.
Key Takeaways
• Position comes first — Dowsett says most amateurs would gain more from a proper time-trial fit than from any component they could buy • An aero bottle returned roughly a 2.5% drag reduction in testing — around 3-4 watts at 40km/h, or 30-45 seconds over a 40km time trial • The aero helmet gave Cavendish another 2.5%, which is why teams started using time-trial-style helmets in bunch sprints • There is no universal fastest tyre — it depends on your wheel, frame and conditions • This was only the second time Cavendish had been in a wind tunnel in his entire career — big gains are still on the table even at the top • Only trust aero improvements measured within the same test protocol; relative gains, not absolute numbers • Drag you cannot hold is not a gain — sustainable position beats aggressive position every time
Position First, Equipment Second
The single most useful thing Dowsett says is also the cheapest. Before you spend a penny on aero kit, get your position right, because that is where the largest improvement lives for almost every amateur.
It sounds obvious until you look at how people actually buy. Riders will drop a four-figure sum on a wheelset while riding a position they have never had assessed and cannot hold past the first hour. Dowsett's point is that everyone is different — there is no single setup that works for ninety percent of riders — so the order of operations matters. Get fitted for the discipline you are riding, learn to hold that position under fatigue, and only then start adding equipment on top of a body that is already cutting a clean hole in the air.
The reason this matters so much is that drag you cannot maintain is not really a gain. A position aggressive enough to look fast in the car park but impossible to hold for 40km is slower over the distance than a slightly higher one you can sit in all day. The win is sustainable aero, not maximum aero.
The Aero Bottle: The Best Value Watts You Can Buy
When Cavendish texted Dowsett a few weeks before the Tour asking about aerodynamics, the wind tunnel turned up a number that should reframe how you think about kit. The aero bottle delivered around a 2.5% reduction in drag.
That figure sounds modest until you translate it. At 40km/h, 2.5% is roughly 3-4 watts saved — and over a 40km time trial that is 30-45 seconds. For an amateur, that is a bigger swing than most of the marginal gains people spend hundreds chasing. And here is the part Dowsett likes: it is functional. You are already carrying water. An aero bottle just makes the bottle you needed anyway do a second job. As he put it, you look at it, you reckon it ought to work, and then it works.
The only caveat is reliability. A bottle that is fast but that you cannot actually drink from mid-effort defeats the purpose — you will dehydrate to save four watts, which is a bad trade. Pick a system you can use, not just one that tests well.
The Helmet That Jumped From Time Trials Into Sprints
The helmet story is the one that tells you how much is still on the table. The aero helmet Dowsett tested with Cavendish returned another 2.5% — a number large enough that a helmet designed for time trials started showing up in bunch sprints, where riders are millimetres and milliseconds apart. When a TT lid is worth using in a road sprint, the advantage is no longer marginal.
What stuck with me was the context. This was only the second time Cavendish had been in a wind tunnel in his entire career. One of the fastest sprinters the sport has produced had spent almost two decades barely testing his aerodynamics. If gains that size are sitting there for him, they are absolutely sitting there for you.
The lesson is not "buy this exact helmet." It is that helmet airflow depends on how you hold your head and back — which loops straight back to position. The same helmet on a rider with a clean back and a low, stable head will test very differently to one perched up and tense. Fix the position, then let the helmet do its job.
Tyres, Wheels, and the Order You Should Spend
This is where most amateurs reach for first, and where Dowsett pumps the brakes. There is no universal fastest tyre. Tyre aerodynamics depend on your specific wheel, your frame, and the conditions you ride in — a combination that tests fast on one setup can be slower on another. Chasing a tyre-shaped gain before you have sorted position, bottle and helmet is spending in exactly the wrong order.
The deeper principle is how you measure at all. Dowsett does not trust absolute numbers between sessions — wind, temperature and protocol all move the result. He trusts the relative improvement when everything else is held constant. That is the bit amateurs can copy without a wind tunnel: pick a consistent test, same loop, same kit, same effort, ideally back-to-back, and only believe a change if it shows up under those controlled conditions. A watts-saved claim from a different day on a different road is not evidence.
What This Means for Your Training
The thread through everything Dowsett says is systems thinking and order of operations. The gains are real, but they only show up if you take them in the right sequence.
Start with position. If you race or ride time trials, get a discipline-specific fit and then practise holding it under fatigue until it is automatic — that is the largest, cheapest improvement available to you, and it makes every component that follows work better.
Then spend on the two big-ticket items: an aero bottle you can actually drink from, and a helmet that suits your position. Each is worth roughly 2.5% on its own, which dwarfs the smaller stuff most people obsess over. Hold the tyre-and-wheel rabbit hole until you have banked those.
And build a testing habit. You will not have Silverstone, but you have a quiet loop and a power meter. Hold conditions constant, compare relative numbers, and refuse to believe a gain you cannot repeat. That discipline is what separates riders who get genuinely faster from riders who just keep buying things.
If you have optimised your position and your kit and the speed still is not coming, the limiter is probably not aerodynamic at all — it is somewhere in your training, recovery or progression. The Plateau Diagnostic looks at the whole system and shows you where the real constraint sits, so you stop spending watts of attention on the wrong thing. Three minutes. Free.
