If you’re leading a Grand Tour such as the Tour de France or Giro d’Italia, you are required to wear the race organisers skinsuit in time trial stages.

Manufacturers often claim that their skinsuits offer significant aerodynamic advantages over a standard suit, so we wanted to find out if having to wear the leader’s suit represented a significant disadvantage, if any at all.

Could Nairo Quintana have won the 2017 Giro d’Italia (in which he came second) had he not worn the leader’s skinsuit during the two time trials?

Aerodynamic drag is the biggest force a cyclist needs to overcome when riding on the flat and typically 80 per cent of that drag is created by the rider.

What you wear is therefore hugely significant. Premium skinsuits claim to offer a significant aerodynamic advantage over more basic, more affordable lycra suits.

We have assembled five leading skinsuits and tested them in a bid to see which is the fastest. As a control we have also tested a lycra Santini suit, similar to that used by the leader of the Giro d’Italia.

This suit doesn’t make use of the special fabrics and optimised placement of these fabrics.

How we aerodynamically tested the suits

To test the skinsuits we teamed up with WattShop to perform some comparative aero testing at Derby Velodrome in a controlled environment.

This has been done in a bid to quantitatively find out which of these suits is the fastest and was completely independent and impartial.

The protocol for the testing was as follows: Three different elite riders wore each suit and did controlled runs at 40kph, 45kph, 50kph and 55kph.

This was done in a bid to determine a drag/velocity profile for each suit, as suits can be optimised to perform better at certain speeds.

Each rider rode their own personal time trial bike, maintaining a consistent position. The riders were Dan Bigham, Jacob Tipper and Jonny Whale, who are all currently national team pursuit champions.

Their ability to ride the pursuit line with precision and ride laps at metronomic pace, helped improve the consistency and accuracy of the data obtained.

The WattShop software is able to interpret the power and speed data for a given run to determine a drag coefficient for each skinsuit at a given speed.

As a control, a basic Santini lycra suit was also tested. The data presented is the average of the three riders at each respective speed.

The CdA is the system drag coefficient for the rider and bike, a lower number equates to lower drag. By subtracting the watts required to overcome drive train friction and rolling resistance we are left with the watts required to overcome air resistance – aero watts.

The aero watts and CdA for each respective suit are presented as an average of the test riders.

Many thanks to WattShop and Brother NRG team for their assistance.

Results

 

Conclusions

Firstly we should point out that although we have made every effort to control variables, and obtain consistent and reliable data, aerodynamic testing is difficult to do and anomalies are possible too.

A skinsuit can also be system dependent. While our data suggested certain suits were universally fast on all our riders (Velotec and Bioracer), other suits were faster or slower depending on who was riding it.

A notable result was the Castelli 3.3 which was within one or two watts of the Endura and BioRacer on two of our riders, but over 10 watts slower on the other.

To find out whether or not we think Nairo Quintana could have won the Giro d’Italia, watch the video.