When riding on a flat course the only real factor on a rider’s speed is the drag caused by wind resistance. It is commonly accepted that the bike accounts for 20% of the overall drag, and your body the remaining 80%.
Therefore, there are lots of products and changes you can make before you decide to spend thousands on a new aero road bike or time trial bike. One such upgrade is a skinsuit.
If you are new to road racing or time trialling it is likely you have been just wearing a pair of bib shorts and a cycling jersey. The question is how much faster could wearing a skinsuit make you?
To record how much faster a skinsuit was compared to a bib shorts/jersey combo we used a CDA (Coefficient of Drag Area) system. The CDA is calculated by tracking a rider’s power output and speed, along with the air density, lean angle, rolling resistance and the rider’s position on the track.
The lower the CDA the more aerodynamic the position; you’d expect a position on a time trial bike to have a lower CDA than that on a road bike.
The same rider undertook four test rides each of six 250m laps. The rider rode both the road bike and the time trial bike wearing standard bib shorts and jersey followed by a wearing a skinsuit. For the avoidance of doubt, the same helmet and shoes etc were used on all test runs.
As you’d expect the skinsuit was faster than the bib shorts and jersey set up. On both the road bike and time trial bike the skinsuit had a saving of around five watts, which over a 25-mile time trial ridden at 25 mph equates to 21 seconds and 28 seconds respectively.
We were slightly surprised by the results and had expected greater wattage savings. For example, if an average rider wore their normal jersey you would expect a wattage difference of between 10-15 watts compared to a skinsuit. The reason for the reduced wattage saving in our testing was due to the the jersey being a particularly good fit.
In conclusion, the results clearly show that a skinsuit is faster. However, how much faster is dependent on the quality of both the skinsuit and the fit of the jersey.