We took 10 road wheelsets to the wind tunnel, here are the results

Nine front road bike wheels sit in front of the fan within a wind tunnel

(Image credit: Sam Gupta)

When it comes to buying aero wheels for a road bike, there are a few considerations cyclists need to make. Compatibility with your bike, groupset and brakes are naturally going to be top of the priority list to ensure you can actually use them, but that's not exactly why we're buying them in the first place, is it? Tyre compatibility is another factor, and while we all get passionate when discussing why we prefer tubeless or clincher tyres over the other, it's still not what gets our blood pumping.

There are two main motives when it comes to choosing the best road bike wheels: those worried about riding uphill will focus on weight, likely before rattling off a rant about rotating weight being worth double (a still annoyingly common myth), but for the majority of us, the most important metric will be aerodynamics. Want to go faster for less effort? Of course you do.

Brands know this, so rare is the day that a brand launches a new set of aero road bike wheels without some sort of claim about how they're faster than their predecessor or the competition. The claim often originates from some sort of wind tunnel or aerodynamics testing, and looks something like "these new wheels are three watts faster than…" or "will save you 32 seconds over a 40km time trial". Naturally, we are forced to take these claims with a pinch of salt, as each brand is biased towards marketing its own product.

Aerodynamics is measured in CdA, or the Coefficient of drag x Area, which is quantified in metres squared, or M². The drag coefficient is effectively a definition of how easily air passes over an item's surface. This is primarily affected by the shape of the item - for example, a bullet will have a lower drag coefficient than a coin, even when their size (or Area) is the same, due to its shape - but it can also be affected by surface material, and that's why many cyclists wear aero socks instead of bare legs. The area is quite simply the item's frontal area, or size.

Returning our focus to road bike wheels, there's an important balance to be struck with reducing CdA while also ensuring the wheels perform well in other areas, such as handling, comfort, and weight. For example, a solid wheel known as a disc wheel will regularly produce the lowest CdA numbers in a wind tunnel, but they are also considerably heavier than a spoked wheel and more affected by wind, which makes accelerating slower, the overall bike heavier, handling more difficult, and crashes more likely.

That's where mid-section wheels come into their own. Averaging around 50- to 65mm deep, these wheels aren't as aerodynamic as their 80- to 90mm deep counterparts, nor are they as light or responsive as the best lightweight wheels, which are often 30- to 40mm deep. They strike a Goldilocks balance and make for the ideal choice for most riders, who are looking for extra speed, without sacrificing handling ability or adding too much weight.

An admission: I didn't perform the testing myself. I was present and involved, but definitely not in charge of the wind tunnel. Even if I were allowed, I wouldn't have wanted to since the calibre of experts present on the day was immense. I was lucky enough to have Jamie Lowden, aerodynamics specialist at Wattshop, as well as Casper von Folsach, one of the aero masterminds behind the Danish federation's 2020 Olympics track success. They were both entirely happy to indulge our wheelset curiosity.

Each wheelset was fitted to the same frame for testing, without a rider present. However, prior to the test, we spent a long period of time testing various wheelsets with a pedalling rider. We saw very similar differences between wheels, but with increased noise (variance in the resulting CdA figures). To achieve the same accuracy of results across all of our testing, we would have needed a lot more testing time and repeats to get the same information. Having found the same differences with less noise using less testing time and fewer repeats, it was a no-brainer to continue the testing without a rider.

I will order them from worst to best based on the average CdA across all seven yaw angles. I will then use this average to calculate the average power required to ride at 30km/h (18.64mph) and 40km/h (24.85mph) based on the following calculation: Power (watts) = 0.5 x AirDensity x CdA x Velocity^3.
Given we have the CdA of the bike alone, rather than a bike with a rider on it, the actual CdA and wattage numbers are small. An approximate CdA for the best time triallists will be around 0.17, rising to around 0.3 for a road cyclist, whereas the CdA values here are between 0.09 and 0.1. The approximate wattage to ride at 40km/h here works out at around 78 watts, which is obviously unrealistic. So, instead of quoting that number, I've calculated the watts saved vs the slowest wheelset on this test.
The results of our testing are representative of just that: our testing. We understand that manufacturers might find different results based on different testing protocols. We don't intend to claim that our results are the final word in road wheel aerodynamics testing, but rather a separate stream of independent testing and knowledge for our readers.
We also understand that aerodynamics is just one of a number of factors that define the best road bike wheels. Weight, durability, width, crosswind stability, ease of servicing, how easily a tyre is fitted, and how easily a tubeless tyre seats and inflates are just some examples of other factors to bear in mind.

The brand very recently won the Green Jersey beneath Marianne Vos at the Tour de France Femmes, and was also used by Wout van Aert for his victory in the men's Tour de France stage 20 time trial. The wheelset in question is the 50/65 - essentially pairing a 50mm deep front wheel with a 65mm rear. Its +10 and +15 degree values actually came out slightly faster than both 8th and 9th place, but the average CdA across the board is 0.00007 higher (and therefore slower) than 9th place. Importantly, that's almost nothing at 0.06 of a watt.

The top step of the podium and gold medal goes to DT Swiss, whose Arc 1100 DiCut 62 wheels were a bit of a runaway winner, providing a CdA of 0.09217. In terms of power numbers, that's a saving of 3.87 watts at 40km/h, or 1.63 watts at 30km/h. Therefore, based on the results of our time in the wind tunnel, if you're looking to buy a new set of mid-section wheels and aerodynamics matters most, then you should be looking at these.

A more typical road cyclist, riding alone and averaging 30km/h, will see even fewer watts saved; fewer than two watts between the best and worst here. Sure, if you're upgrading from a box-section alloy wheelset, then the gains will be greater, but spending too much time worrying about the difference between the aero performance of two high-end wheelsets is a fool's errand. As mentioned in our caveats above, if this is the position you find yourself in, our recommendation would be to find a wheelset in the ballpark, then ask yourself what else matters to you, so you can focus your energy on other considerations like ease of servicing, tubeless compatibility and more.

With some wheelsets costing around £1,000 ($1,500) - Hunt's entrant in 2nd place is just £1,189.00 - and top-end wheels costing £3,000 ($4,000), the one to four watts you might save by buying a premium pair of wheels would present pretty awful value for money. And sure, a premium set of aero road wheels will definitely add to the visual appeal of your bike, but in a pragmatic approach to going faster, there are better ways to spend that money.

For £1500, you could even book a day in the wind tunnel with Wattshop themselves and ask them to make you faster. You could alternatively work through our guide of watts saved in order of spend and get faster by yourself. Or you could take a different approach and you could buy one of the best turbo trainers to make your training more efficient. You could do any of that, shave your legs, fuel your rides with more carbohydrates, eat less junk food, train more consistently, add strength training to your plan, or simply ride in a more aerodynamic position.

Josh is Associate Editor of Cyclingnews – leading our content on the best bikes, kit and the latest breaking tech stories from the pro peloton. He has been with us since the summer of 2019 and throughout that time he's covered everything from buyer's guides and deals to the latest tech news and reviews.

On the bike, Josh has been riding and racing for over 15 years. He started out racing cross country in his teens back when 26-inch wheels and triple chainsets were still mainstream, but he found favour in road racing in his early 20s, racing at a local and national level for Somerset-based Team Tor 2000. These days he rides indoors for convenience and fitness, and outdoors for fun on road, gravel, 'cross and cross-country bikes, the latter usually with his two dogs in tow.