Video: How much aero difference does cycle clothing make?

Aero is everything, claim Specialized, who last year built their own wind tunnel at their Morgan Hill, California headquarters to allow the design team unlimited access to a very important tool in the study and development of producing aerodynamic bikes and products.

In between designing new bikes, they’ve been publishing videos to Youtube such as the recent “to beard or not to beard” video, looking at whether facial hair makes much difference to your aerodynamics. In their latest video they’ve looked at the more important issue of what impact your cycle clothing has to your aerodynamic efficiency.

You, as opposed to your bike, account for about 80% of the wind resistance you face when cycling, so as well has having a good position that minimises your frontal surface area, the clothing you wear can make a difference. But how much difference exactly? That’s what the Specialized video reveals, and the findings are interesting.

Mark Cote and Chris Yu, Specialized's aero research and development guys, look at the difference between casual club clothing and form fitting clothing. They've not only looked at the differences with summer short sleeve jerseys and shorts, but long sleeve winter clothing, the sort of clothing we in the UK spend a good chunk of the year in.

The first test, with a wind speed of about 50kph (31.25mph), reveals close-fitting winter clothing and long-sleeve jacket to be worth 83 seconds over 40km (25 miles). That’s a significant difference, and if you extrapolate that to a 100km or longer ride you’d certainly get to the cake shop a fair bit sooner.

Moving onto a summer jersey, and the difference is even more significant. As well as switching from a club fit jersey to a race fit jersey, they also went down a size, from medium to small, to get an even closer fit. The same testing conditions reveal the form-fitting jersey to be worth 91 seconds over the same 40km distance.

Some interesting results there. Of course, it’s well known that tighter fitting clothing is faster; that’s why skinsuits are worn in time trials and racers try and squeeze into the smallest clothing they can get away with - like Bradley Wiggins wearing a size small skinsuit in the Tour de France despite being over six foot tall. We’re now seeing racers, especially sprinters, wearing skinsuits in stage races a lot more this year for the same reason, and you only need to look at the popularity of Castelli's Gabba, a stretchy, slim-fitting jersey designed for bad weather, to see the importance attached to be aerodynamic.

The difference between clothing this hugs the body like a second-skin and baggy clothing that billows in the wind is more than can be saved by fitting far more expensive aero products to your bike.

As Chris Yu points says: “We’re talking about a difference here that is more than race wheels. Think about that. Several thousand dollars to go into race wheels, or think about your kit a little bit.”

So, if these claims are to be believed, clothing makes a big difference. If you want to go faster, wearing a closer fitting jersey or jacket is a really easy way to reduce the resistance you have to overcome when pedalling, and it's a lot cheaper than a new set of race wheels.