Bike and cycling kit manufacturers are really promoting the aero benefits of their equipment and introducing a lot of lines with aero benefits at the moment. You could spend a lot of money making yourself more aero, but which items are likely to give you the best aero benefits for their cost?

>>> How to be more aero on your road bike

To find out, we headed up to the De Havilland windtunnel at Glasgow University, part of the National Windtunnel Facility. Along with, it’s developed its expertise in testing cyclists and their kit for their aero efficiency.

The National Windtunnel Facility has developed cycling-specific analysis software

The National Windtunnel Facility has developed cycling-specific analysis software

We were hosted by Planet X Bikes, which had brought along its Planet X-Northside pro rider Ben Hetherington to test its kit’s aero benefits.

>>> Are longer cycling shorts more aero?

Ben started out in a standard vented helmet and relaxed fit jersey and shorts, which he gradually swapped out for more aero kit. Each time, his drag was measured for a minute with the wind tunnel running at 47kph, using highly accurate strain gauges attached to the platform on which he was pedalling.

The measuring platform cost £500,000 to install

The measuring platform cost £500,000

In his starting kit, Ben would have to put out about 400 watts to overcome wind resistance at this wind speed, but by the end of the changes he’d saved around 50 watts. The largest gain came from swapping from the jersey and shorts to a skinsuit, which saved over 30 watts.

Ben cycled on a platform in the test area of the wind tunnel

Ben cycled on a platform in the test area of the wind tunnel

Swapping to an aero bike saved seven watts, whereas changing from 30mm deep aero wheels to 55mm deep aero wheels did not show a saving in drag at zero yaw angle.

>>> Aero bike buyer’s guide

But the lowest price per watt saved came from covering up the buckles and vents in Ben’s shoes with a pair of aero overshoes. Although the power saving was lower than a skinsuit, at 18 watts, the lower cost of the overshoes makes this the biggest gain for your buck.

We’ll be publishing more windtunnel videos over the next few months, so look out for more marginal – and not so marginal – gains to come.

  • Janusz Gajos

    The perfect scenario of a skinny guy in a flat back/forearms position putting 400W and clocking 29mph is way too detached from the reality. It produces real but irrelevant inflated numbers.

    Instead I’d like to see an average build sporty guy at around 20mph 200-250W spending half the time on drops on a bike with bottles, computer, spare kit in his pockets etc…

    Now, that would make an interesting, relevant video enabling consumers to make “educated decisions”.

  • The video is clever and informative. CW & Planetx had the courage to examine products & their benefits so that everyone can make an educated decision based on data. Upgrading wheels & frame deliver little benefit at high speed / therefore at low speed deliver even less benefit. Dont be so quick to be dismissive, its normally an indicator that you dont know what you are talking about. Specialized Venge Vias, all the marketing bs says its just for you

  • Janusz Gajos

    So which bit of “irrelevant to vast majority of cyclists” do you disagree with exactly?

  • myultralite

    Disagree, 47kmph is those who are aiming to do 50kmph & win a race. If you cannot sustain 40+ and you have $3K burning in your pocket, take your family / or bike on holidays, enjoy the sport and forget the marketing bs

  • Altimis Nuel

    Aero Frame is bullshit marketing

    TDF riders in the past avg is not that too difference these day TDF and they have poorer tech, rode steel&aluminum bike, not aero shaped.

    Just pure marketing bullshit . . .

  • Chris Broome

    yes that’s because it wont appeal to anyone enough to increase any sales unless they spruce it up. Ride at 15mph then the gain is likely to be less say 5watts which isn’t going to turn anyones heads. The test should have been done at several levels representative of a leisure rider, amateur racer and then a semi pro or something to give an idea of what anyone could achieve. A saving of 18 watts at 400 watts could technically equate to 9 watts at 200watts output.

  • bdh


  • Janusz Gajos

    47kmh… Another aero test at speeds completely irrelevant to vast majority of cycists… What’s the point?

  • Anthony


  • shame I can’t seem to find what these £14.99 aero overshoes are. Not appearing on Planet-X website that I can find.

  • Gilles Dupon

    They tested at 0 yaw.. which isn’t really representative for anything really.

  • Frobble

    Vision will be _very_ unhappy regarding the 30mm/55mm profile depth making zero difference. Could they argue that the wheels not making the same turns needed for 47kmh (i.e. static front wheel, rear wheel on turbo) would invalidate the result?

    // Gets coat. Leaves. Out to the shops for overshoes.