What are the best aero upgrades to save watts for less?

We've been to the National Windtunnel Facility in Glasgow to find out which items of cycling kit offer the best value aero advantage

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 Visualbikefit.com, 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.

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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.

Which aero gains are the most cost efficient? - full results

ItemWatts savedCost Watts saved per pound spent
Carnac aero helmet vs non-aero vented helmet18w£79.99£4.34/w
Carnac skinsuit vs relaxed jersey and shorts32w£79.99£2.53/w
Aero overshoes vs Planet X shoes, no covers 18w£14.99£0.81/w
Planet X EC-130E aero bike vs RT80 lightweight bike7w£2499.99£379.94/w
Vision Metron 55m wheels vs Vision Team 30mm aero wheels0w£1349.99 each£0/w (equal)

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.

Paul Norman
Paul Norman

Paul started writing for Cycling Weekly in 2015, covering cycling tech, new bikes and product testing. Since then, he’s reviewed hundreds of bikes and thousands of other pieces of cycling equipment for the magazine and the Cycling Weekly website.

He’s been cycling for a lot longer than that though and his travels by bike have taken him all around Europe and to California. He’s been riding gravel since before gravel bikes existed too, riding a cyclocross bike through the Chilterns and along the South Downs.