CIRRUS Aerodynamic Drag Measurement System
Real World Aero Testing Made Easy
The CIRRUS System
CIRRUS allows cyclists, coaches, and bicycle manufacturers to test and improve their aerodynamics in a realistic environment without the hire and travel costs of specialised testing sites, such as wind tunnels.
A simple, intuitive outdoor aerodynamic drag measurement system that automates the testing process, allowing riders and coaches to focus on what really matters – data-powered performance improvement.
Achieving precise and consistent results requires numerous calibrations and calculations. Our rider portal streamlines the testing experience, delivering clear and simple results. It benchmarks aerodynamic drag and indicates if implemented changes are improving or degrading a cyclist's performance.
The CIRRUS system is available now for commercial use.
How CIRRUS Works
Our simple 3-step process to real-world aero testing
Set Up
CIRRUS requires a bicycle with a power meter. The system then adds on three extra sensors Alto-Stratus (for wind speed, direction and altitude), FORMA (for body position), and our wheel speed sensor.
Ride
The cyclist rides along a course with less than 1% gradient, for approx 600m to 1000m. Ideally, the course needs to be relatively straight and free from too many bumps or obstructions - cycle paths and local roads are usually suitable.
Result
As they ride, data collected from the sensors is stored on a data logger, and then uploaded to the cloud system. Precise aerodynamic drag measurements from the sensor combination can then be instantly viewed on the portal.
What's Included
• ALTOSTRATUS Wind Sensor
• FORMA Body Position Sensor
• TEMPO Speed Sensor
• Data Logger
• Access to Ride Portal
Results & Analysis
The Rider Portal
• Performs all calibrations and calculations required for precise aerodynamic drag measurement seamlessly and automatically so that users can focus on improving performance
• Delivers precise and simple data in a clear layout - no need for technical knowledge
• Allows comparison of data between multiple rides
• View if implemented changes are improving or degrading performance quickly
Wind Sensor
The ALTOSTRATUS
Our patented four port sensor design measures wind speed with 0.2% accuracy, wind direction with 0.1 degree precision, altitude, and air density. Accurate aerodynamic drag measurement can be taken in almost any wind conditions that are safe to cycle in. In addition, the pressure sensors in the probe are designed to eliminate any water ingress.
Road gradient is measured through matching multiple barometric measurements with GPS locations, providing a precise elevation profile along the course. Undulations and mild gradients are measured and accounted for, allowing for a greater availability of test locations.
Body Position Sensor
The FORMA
About 75% of a cyclists drag comes from the rider’s body position. The FORMA body position sensor consists of three infrared lasers which measure a cyclist’s head and chest position on the bicycle, ensuring that any movement that takes place while the rider is testing can be accounted for. Real-time visual feedback from the sensor is fed back via the Streamlines app, which runs on most Garmin bike computers.
Speed Sensor
The TEMPO
Our proprietary wheel speed sensor measures time to the microsecond level. This greater precision is instrumental to the CIRRUS system drag measurement overall accuracy. The TEMPO is also at least ten times greater than other existing speed sensor market options.
Why Choose CIRRUS
Essentially, the CIRRUS system has optimised the entire aerodynamic testing process, from start to finish, so that riders, coaches, fitters and manufacturers can perform multiple end-to-end tests in as little as two hours, even in windy conditions.
The portal interface allows the user to see simple and clear data that highlights performance improvements (or degradations) without needing any understanding of the calculations and automatic calibrations happening behind the scenes.
Testimonials
“WT cycling team riders are not often available for wind tunnel or track testing. Testing with Streamlines makes it possible to test and train on the spot and give instantaneous feedback on aero gains.”
Mathieu Heijboer, Head of Performance, VISMA LEASE A BIKE
Request Commercial Information
The CIRRUS system is available now for commercial use.
There are two distinct customer packages, one for fitters and coaches focused on
rapid rider development, and another for advanced equipment development and large rider
programs. If you are interested in the CIRRUS system, please fill in the form
below and we will get in touch with you. Alternatively, you can email us at
commercial@streamlines.aero