I spotted this aero sensor on the front of the Jonas Vingegaard P5.

Before the final time trial of this year’s Tour de France, we want to go back to the first time trial, and more specifically to an aerodynamic sensor that we spotted on Jonas Vingegaard’s Cervelo P5.

We spotted this sensor on Vingegaard’s bike as he headed for the morning scout, and again, upon his return, the team mechanics removed it from under the handlebars. Vingegaard finished third in this time trial a few hours later, a first glimpse of his potential in the general classification on this Tour de France. Visit our technical time trial gallery to view these photos. After several conversations, we can now confirm that the sensor comes from VeloSense, a specialist in aerodynamic sensors in Formula 1 and cycling.

In short, it is designed to measure aerodynamic drag, wind speed, altitude, wind direction, etc. in real time, which teams can then use with power and other data to optimize position, equipment and pace.

The Velosense Ventos is an aerodynamic sensor for measuring wind speed, yaw angle and altitude.

Velosense is a British company created by Formula 1 aerodynamicists Barnaby Garrood and John Buckley. Both men are avid cyclists and wanted to bring their aerodynamic expertise to the world of cycling.

I spoke with Buckley, who confirmed that the sensor on Vingegaard’s bike is from Velosense: “It’s one of our Ventos sensors on a center mount. It measures the speed, direction and altitude of the wind.

The Ventos is a variation of the patented aerodynamic probe from Velosense Formula One.

According to the Velosense website, Buckley and Garrood started with their patented probe design from their Formula 1 days, which measures wind speed and yaw angles.

The yaw angle and precise elevation have proven to be a challenge for designers and manufacturers of aero sensors. The Ventos probe measures the yaw angle, and Velosense claims the elevation accuracy is less than 8 inches. Altitude accuracy is particularly important for an air sensor to provide accurate CoA calculations and this level of accuracy is almost unknown.

A better shot of the Ventos on a time trial bike.

Although he couldn’t go into the details of working with the teams, Buckley said, “We have worked with selected partners to improve their performance, and in this case they are measuring wind speed and direction before the TT ”

“The primary use of the sensor is to measure aerodynamic drag (CoA), but it can also map wind speed and direction along a course to provide riders on a team with detailed information about the wind around the course. course, highlighting areas that may have increased winds. “

The Ventos has three main uses;

  1. Traverse lap testing: the runner makes a round trip starting and finishing at the same place. Velosense claims that ventos can measure CoA with velodrome test accuracy levels.
  2. Snapshots: Velosense can analyze any session using an algorithm that automatically selects the appropriate sections within a ride to track a rider’s CoA and ability to maintain position throughout the ride. a trip. The algorithm checks speed, braking, turns, etc. to find these segments and provide a snapshot of a cyclist’s CoA at multiple points along a route.
  3. Real-time CoA and Power Advantage: When paired with a compatible head unit, the Ventos can calculate and display “real-time” CoA. This real time is actually a timed moving average. Velosense currently recommends an average of 45 seconds, but is working on technology to bring it down to just 15 seconds.

Velosense also aims to use GPS to create an average per section. As technology improves, the hope is that this section-based test will have similar accuracy to the crosshead test.

The Ventos also calculates what Velosense calls a rider’s power advantage, using speed and body position. This compares the current position of the rider to the position data acquired previously to estimate the number of watts a rider could gain or lose from the “ideal” position.

Velosense suggests that this feature could help riders determine whether an aerodynamic or upright position will be best going uphill.

Buckley couldn’t go into too much detail, but explained that the Ventos pairs with another Velosense sensor, the Zenith, to measure the rider’s head position, torso position, and whether the rider is seated. or standing. All of this is used in the calculation of the Poweradvatnage metric.

Velosense believes that the combination of body position and data from aero sensors will allow riders to hone their positions, measure stance durability, and better understand how their body position affects aerodynamic drag.

While Buckley couldn’t confirm who the selected partners are, we can make a pretty good guess.

Velosense currently only supplies sensors to select partners as it refines the final offering, but its long-term plan is to provide affordable and accurate aero testing to the public. “Velosense’s goal is not just to measure a rider’s drag, but to combine knowledge of body position and drag to enable the rider to ride more efficiently and comfortably,” Buckley said. .

“Our long-term goal is to create a consumer device that will make aero testing more affordable and efficient for competitive cyclists. Currently, we are working with selected partners to improve rider performance and reduce fatigue through our aerodynamic and body sensors. I can’t disclose who we work with, but I can confirm that the sensor in the photo is one of our Ventos Aero sensors.

John buckley

What is perhaps most interesting is that the Jumbo-Visma and Mercedes F1 teams use variations of the Velosense probe, which is a testament to Velosense’s experience in the field of aerodynamics. Jumbo-Visma has dominated the time trial this season and Mercedes has won the last seven world championships.

It is expected that Jumbo-Visma will use the sensor again during reconnaissance before Saturday’s TT. I asked Buckley why the team would use the Ventos sensor on the morning of the first time trial, as it seemed unlikely the team would adjust the riders’ positions so close to a Tour de France TT.

“The reason a sensor is used on the race day sighting lap is because it gives the team an accurate measurement of wind speed and direction across the course,” explained Buckley.

The mechanics removed the Ventos from Vingegaard’s P5 immediately after the sighting lap.

Of course, similar data is available with modern weather applications and a local weather station. Buckley explained that “These published measurements are taken 1.5 meters above the ground in an open area. The local wind speed and direction that the rider actually encounters at different points on the course can vary by up to 90 ° based on half the speed.

“A simple example would be a road with buildings on both sides. The direction of the wind must change for it to pass around the building. Therefore, the wind in cities generally moves in the direction of the roads. The effect is called “channeling” and can also occur with hills, canyons, hedges, etc.

Buckley explained that the Jumbo-Visma team uses this information to create more detailed racing strategies, relay areas of unexpected wind or gust changes in an opening, and inform equipment selection decisions.

“During the development of the Velosense aerodynamic probe, we often saw sharp wind peaks that we initially attributed to hardware or software issues. When we mapped these spikes on the GPS, we generally found that they corresponded to doors in hedges or spaces between buildings. We are now able to provide wind information throughout a course showing specific points where wind speed can increase or changes in wind angle can be noted and the rider can approach these sections from the side. upwind of the road, reducing the chances of being blown off the road. If the winds are strong, a less aggressive wheel option may be chosen.

Buckley also explained that the team could use the data collected during the morning reconnaissance for correlation and comparison. “For climbers, watts per kilogram is the measure, for time trials, it’s watts against CoA. Therefore, in order for teams to be competitive, they not only need to know the power of their riders on the same day, but also to have some measure of their aerodynamic drag, as it often deviates in races. drive and wind tunnel.

I spoke to Mathieu Heijboer, performance manager at Jumbo-Visma for an upcoming Nerd Alert podcast and asked him how the team uses the Velosense Ventos.

Heijboer reiterated the interest in creating a wind profile for a race day course to inform wheel selection, and also explained how the team used the Ventos to optimize Vingegaard’s time trial position. despite Covid-19 lockdowns in Denmark during the winter.

Surprisingly enough, Heijboer explained that Vingegaard had never been in a wind tunnel and was the fastest runner in the fifth stage time trial not to have optimized his position in a wind tunnel.

For more information visit www.velosense.com


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