The power of aero
How can I get faster? A deep dive into TT aero gains
How can I get faster? A very simple question with many very complicated answers which effectively break down into two parts: physiology and aerodynamics. With the World TT Championships coming up, we’re going to take a deeper look into the time trial world and what better place to start than the UK domestic scene?
With a small gap between European race days and under the premise of heading back to the UK to see family, I found myself on the startline of the National 10-Mile Time Trial Championships. The “National 10” is held under the rules of Cycling Time Trials (CTT) an independent governing body which rules the weird and wonderful world of the British domestic cycling scene, something I wrote all about back in 2020.
This year was my first go at senior TT nationals where I placed eighth, not bad but certainly not great. Without sounding above my station, I came to win or at least podium. At first it didn’t make sense to me how I’d come so significantly short.
Riding back home after the race, the cogs in my brain were in overdrive, so I asked my aero-man George Fox to run the data. I headed over to Twitter to write all about it, and got a fair bit of attention. I was called stupid (numerous times) for certain equipment choices, and some kind soul even made a YouTube video breaking everything down for me.
Looking through all the responses, I realised that few understand the true power of aerodynamics, myself included. In this article, I’m going to break everything down.
The course:
The championships used the ‘V714’ course in Yorkshire: 10 miles long (16.1 km), out and back along a non-busy ‘B’ road. 5 miles in one direction, around the roundabout and 5 miles home. The course is fast, and the road surface mostly good. There were four mini motorway bridges, but my total elevation for the ride was only 18 metres (59ft), so it was effectively pan-flat.
The nature of the course meant it was a true power to CdA test (CdA is a representation of a rider’s aerodynamic efficiency). When it came to pacing, it was relatively simple given the out-and-back nature of the course. However, there was a slight headwind on the way home, and the four motorway bridges (around 30 seconds each) threw a slight spanner into the ‘typical’ pacing plan.
The results:
Former pro, John Archibald crushed the field and won by 44 seconds. John has all the attributes of a great time trialist and was a class above everyone. Behind John, there was a battle for the medals with eight riders within 35 seconds of each other.
| Name | Team | Time | Average Power (W) | Average Speed (MPH) | Watts/Kilogram |
| John Archibald | WattShop | 17:53 | 425w | 33.5 | 5.52w/kg |
| Chris Fennell | Independant Pedaler- NoPinz | 18:37 | 430w | 32.23 | |
| Michael Gill | Saint Piran | 18:40 | 391w | 32.14 | 5.51w/kg |
| Richard Bussel | Aerocoach | 18:53 | 31.77 | ||
| Will Perrett | Ward Wheelz | 18:54 | 393w | 31.75 | 5.46w/kg |
| Ashley Cox | Team Bottrill | 19:00 | 390w | 31.58 | 5.74w/kg |
| George Peden | Team PB Performance | 19:06 | 375w | 31.41 | 5.59w/kg |
| Joe Laverick | Hagens Berman Axeon | 19:08 | 412w | 31.36 | 5.89w/kg |
| Adam Duggleby MBE | Vive le Velo | 19:09 | ~400w | 31.25 | ~5.26w/kg |
Thanks to all the riders who shared their data with me. As everyone was on different power meters, these numbers have to be taken with a pinch of salt.
The data:
Looking at the table, you can see there is more to time trialling than just raw power or even watts per kilogram. Although, given the how similar some of the wattage figures are, it is worth noting many the riders were using different power meters. Still though, there are multiple parts to the time trialling puzzle, and the winner is usually the person who puts that puzzle together best. Power, pacing and riding technique are all important, but a key piece to it all is aerodynamics.
Aerodynamics has come on in leaps and bounds in recent years. Coming through the youth ranks in the late 2010s, I was guided on nutrition, training and recovery; it was rare to hear about aerodynamics. Some coaches were ahead of the game and gave little snippets of information, but that was the exception rather than the rule. I distinctly remember once being told that equipment accounts for nothing and it’s all in the head, I should just pedal harder.
Aero what?
Aerodynamics is effectively the way air moves around things. In cycling, we refer to how aerodynamic a rider is as their ‘CdA’, the coefficient of aerodynamic drag. CdA is a dimensionless number which is a result of drag size, shape and texture.
Aerodynamics is extremely important because aero drag force is proportional to velocity squared, so the power required to overcome it is proportional to velocity cubed. So in layman’s terms: the faster we ride, the harder it becomes to go even a little faster.
If we look at my ride, I averaged 412w with a normalised power of 414w for 19:08. At around 70kg, this places me at 5.89w/kg – presuming my power metre is accurate.
There are three options if I want to equal John Archibald’s time:
- Keep my current equipment and position, but produce 500 watts – approximately 20% – more power than I was capable of.
- Simply maintain the same power, but reduce my CdA to 0.168, an extremely aerodynamic position almost unheard of on the road.
- Alternatively, if I lowered my CdA to 0.19, the power required drops to 460 watts. That’s still a significant 45-watt jump and well beyond what I can produce.
Wind tunnel testing back in May suggests my current CdA sits at around 0.207. At the pointy end of the sport, a CdA above 0.20 for a rider of my size isn’t great. If I was capable of doing Filippo Ganna power numbers, then maybe I’d be able to overcome my aerodynamic inefficiencies, but unfortunately, I cannot do 500w for 20 minutes.
Equipment race
In my Twitter thread, I stated that time trialling has become “an arms race”. This proved a controversial comment, but thankfully, I’m not limited to 280 characters here and can elaborate much further.
The good news is you do not have to remortgage the house to be competitive, have fun and race time trials. In fact, when it comes to time trialling we are all racing against the clock and ourselves. Regardless of equipment or upgrades, simply bettering our own personal best or most recent time is motivation enough.
That said, to challenge for the podium in the National 10 and 25, I believe you do need good equipment, as well as a few watts, pacing, position discipline, and so on and so on. Of course, part of the fun of time trialling is nerding out on equipment upgrades, and those upgrades come much easier with a bigger budget. But money isn’t always a shortcut to TT success.
On one hand, there is the newly released WattShop Anemoi Basebar, which is reported to save a mind-boggling half second per kilometre at 50kph (yaw angle dependent). The starting price for this basebar, not including the aero extensions, is a cool £1,540.
On the other, Michael Gill placed third using a frameset from 2009. Gill has maximised this frame’s potential, both with his own efforts and also with his chosen upgrade route, helping to improve the airflow over him with an improved position and the bike with ‘slippery’ tech.
Equipment choice is vital, because as we mentioned earlier… aerodynamics, speed, power. Even tiny aerodynamic improvements can make huge differences when the speeds are high. Perhaps the most famous example of this was the 1989 Tour de France final time trial battled out between Greg LeMond and Laurent Fignon. LeMond used the then revolutionary aero-bars and put 57 seconds into Fignon in 20km. Had Fignon used the same bars, he likely would have won the Tour de France – that’s the power of aerodynamics.
Given all that, it was hardly surprising the sheer number of comments I received questioning some of my equipment choices. The fact is, though, most of my equipment weren’t ‘choices’ at all, but sponsor-correct components on a team-supplied bike.
I ride with the Hagens Berman Axeon team and we have very supportive sponsors. I am very grateful for those sponsors support, without whom the team, or my 2022 racing season, do not exist.
Although we have team sponsors, we don’t necessarily get access to their whole equipment range. For example, I would have liked to have a bigger chainring to increase drivetrain efficiency, and while SRAM makes a 56T chainring, it’s not something that we had available in the team warehouse. It was also pointed out that swapping my tyres for the fastest available option could have saved me around 15w, and while that may be true, it would have meant going rogue on team-issue rubber, and not really an option.
There is a certain irony that professional riders often have less optimised equipment than amateurs. While top teams can afford to select from outside their sponsors’ catalogue for the fastest equipment, lower-level teams rely on those sponsorship relations to stay on the road, meaning there is less wiggle room.
Take BikeExchange-Jayco. Their official kit partner is Alé but for time trialling they have a partnership with British brand Vorteq. Vorteq creates custom skinsuits with a price tag of around £2,750. That’s £2,750 per suit. Riders like Simon Yates can demand faster products and live in the grey area of sponsorship contracts, and Simon, for one, has in turn repaid the team’s investments by delivering time trial success on several occasions.
But the majority of WorldTour teams and riders must stick rigidly to sponsor correct equipment. Amateurs and time trial specialists, on the other hand, have the freedom to invest in any and all the kit their bank account can handle. This is the reason amateurs quite often have much faster setups and much lower CdAs. Unbeholden by the regimented structures of the WorldTour, time trial specialists in the UK can throw the UCI rulebook to the wind when it comes to position and cherry-pick their equipment too.
Take the skinsuit example again. A WorldTeam might have a sponsor with the fastest skinsuit in the peloton, but their tyre sponsor’s best time trial offering only comes in fourth on the list of fastest tyres. The most competitive riders at the pointy end of the UK time trialling scene will often have tested and optimised every aspect of the entire bike and rider system. Want to see the true “aggregation of marginal gains”? Come watch next year’s National 10.
None of this is to say that any WorldTeams are unaware of the potential gains to be had. Time trials only make up a tiny percentage of a pro’s total race kilometres in a season. Take Primož Roglič, for example. At the time of writing, he has ridden 120.21km of TT(T)s this season, less than 1.5% of his total race kilometres. Personally, my time trialling equates to around 1.3% of my total.
Team budgets are already stretched to the maximum, so trying to free up cash to optimise everything on a TT bike, when you will inevitably be battling with sponsors too, is always a difficult sell.
For a while, there were questions as to why riders that transferred across to Team Sky/Ineos seemed automatically to become better time trialists. Yes, some of that will be training, but a lot will be the extra attention to detail in equipment choices.
The inclusion of a team time trial in the Tour de France route is practically the only time almost all teams are forced to go the extra mile in time trial preparation for their entire squad.
Aero in practice
Perhaps the greatest example highlighting the power of aerodynamics is Dan Bigham’s recent Hour Record. Dan rode 55.548 km for the hour, 459 metres further than Victor Campenaerts.
It is widely agreed Dan doesn’t produce the same power as Campanaerts, who himself required less power than Bradley Wiggins before him, but with Dan’s CdA reported to be around 0.155, he simply doesn’t require as much power despite travelling even faster. In fact, Dan needed only 350~360 watts to break the record (according to data published by WattShop). The graph below shows just how strong the power of aerodynamics is.
With credit to Dan, it is not as simple as getting super aero and riding at ~360 watts, even as difficult as that sounds. Lots of simple yet critical elements went into his Hour Record, so not a single watt was wasted. It’s a topic Dan delved into on a recent episode of the CyclingTips Nerd Alert podcast. Going fast in an aero position is like a dark art: maintaining position discipline, resisting the urge to shuffle on the saddle and hold the quickest line around the banking, all while maintaining maximum effort, is no mean feat. Having the best equipment and a low CdA in the wind tunnel is just one part of the puzzle – maintaining that position while cranking out the watts and experiencing a severe lack of oxygen to the brain is another piece entirely.
The National TT and everything that came with it reignited a fire inside of me, and it also got me thinking: can I get on the podium without breaking the bank? In other words, can I prove myself wrong, and prove watts are still more valuable than pounds?
I don’t yet have a contract for next year as I ‘age out’ of my current team (a whole story in itself). I don’t know what I’ll do in 2023, for who or in what colours. However, on the TT front, I do have an old 2017 Cervelo P2 frameset sitting in my parents’ attic. Could I build that up on a budget and go for the win? Maybe.
I’d need to step up in terms of power output too. Archibald wasn’t just a class above from an aerodynamic perspective, but from a power and stability perspective too. More power, less aerodynamic drag and riding smoother, sounds like I’ve got a bit of work to do.
Getting the tone of this article correct was a difficult one. On one hand, I have some ridiculing me for putting people off the sport by pricing them out and saying it’s an arms race. On the other, people call me stupid for not buying a faster skinsuit or tyres. Time trialling is what gave 15-year-old me the cycling bug. My first race was on the ‘Fonaby 1 Lap’ TT course in Lincolnshire, and as I rose up the ranks I loved that I was beating guys on world-class bikes with my comparatively budget setup.
I’d hate to think that writing this puts anyone off time trialling. Trust me, TTing is a great corner of the sport with a friendly community. Whether you’re on your £150 road bike or £10,000 speed machine, time trialling is all about getting the most out of yourself, and going as fast as you can.
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