Eagle-eyed viewers watching track cycling at the Commonwealth Games this weekend might spot that Team England's skinsuits are not completely smooth, but instead contain ridges beneath the top layer.
The ribbed base layers worn by members of the Team Pursuit squad, for example, on Friday are part of the "next evolution in how aero clothing works", according to Sam Calder, the managing director of Rule 28 Clothing (opens in new tab). They are one of a few companies at the forefront of skinsuit technology in the UK. Rule 28 are not directly supplying the English riders at the Games.
Team England progressed through to the final of the men's Team Pursuit on Friday evening, where they will face New Zealand for a gold medal; they might have been helped, in part, by the funky aero advances they employ.
"You've seen these sort of striped fabrics that have been on the arms for the past 10 years or so," Calder explained. "This is the next evolution of that, it's a slightly more refined way of doing things. The principle for the most part is similar, there are a few different things going on, but the idea here is to create some surface roughness to energise the boundary layer of air as it moves around the arm.
"The arm is a fairly stable shape, it's a very unaerodynamic shape. You can't modify the shape of any body part, so you have to play with the shape of the arm you have. What these striped fabrics do is that the roughness means that the air travelling along it, the textured fabric there distorts the flow.
"It trips it, makes it turbulent, and that sort of spinning vortex that it creates, then infills the pocket of low pressure left behind the arm as it moves through the air. This ribbed fabric with the smooth over layer works pretty much exactly the same, it can just be a bit more targeted."
Similar clothing was employed by riders at the Tour de France this month, and Team England are not unique in using it - other nations at the Commonwealth Games and beyond are at the cutting edge too.
It is better to wear the ribbing as a base layer rather than on the skinsuit itself, as this creates an extra effect.
"Testing the base layer by itself does not perform well," Calder said. "Testing the base layer with a skin suit that has sort of traditional ribbed fabric already on the arms doesn't perform well. There you're sort of creating an interference pattern, the traditionally textured fabric and ribbed base layer sort of competing with each other. They end up creating too much drag.
"The happy medium is a smooth arm skinsuit and the ribbed base layer. In general, it tends to outperform the traditional skinsuits. However, it's not really one size fits all."
If you are intrigued by the benefits of the base layers, you can buy them from Rule 28 for £149.99 and their rivals Huub for the same price, but they might not make you immediately as fast as Dan Bigham or Charlie Tanfield.
The advances in skinsuit technology is believed to be one area that the UCI, cycling's governing body, is looking to simplify the rules around at the moment. It is a difficult area to legislate on, but the body is thought to be moving towards clearer, easier to understand regulations.
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