The technical development pact aims to help the illustrious French tyre maker further refine its racing cycle tyres.
Verve will provide Michelin’s development team with InfoCrank power meters, so it can accurately measure power savings against power inputs.
The Verve InfoCrank is the only available cycle power meter that measures input power accurately and repeatably, without the need for continual recalibration. Precision instrumentation is housed in the crank arms in the direct load path and transmits load data from each crank at a high sampling rate, via the ANT+ protocol.
Accurate power data is key to measuring the performance of tyres in action. It’s relatively easy to measure tyre performance on a static rig, and extrapolate that into presumed energy savings (or losses) on the road. But until now it’s not been possible to determine this empirically because the current generation of power meters does not allow developers to meaningfully compare datasets from different on-the-road test sessions.
Michelin developers met with Verve Cycling chief engineer Richard McAinsh at Eurobike 2014, where they were looking for a power meter to support the company’s test methods, simulation tools, and tyre performance analysis equipment. InfoCrank, they said, was the most suitable they had found for their testing purposes.
The company – which started life making bicycle tyres – is renowned for its extensive R&D activities, which take place at its test center in Ladoux, France.
It applies this commitment to R&D methods to its bicycle tyre program, which shares the development facilities. Michelin’s current Pro4 racing tyres were launched with detailed performance data on grip, and notes on the equipment used to log the test data—a bicycle with accelerometers, angle sensors, and speed sensors, monitored by telemetry.
The Michelin engineers were especially looking for a power meter that would permit them to measure ups and downs in the pedaling cycle during outdoor rides, with greater accuracy. For this, a much higher sampling rate is required than the usual once-a-second of even the best previous-generation power meters.
Verve was able to show them that InfoCrank samples at 256 Hz (from each crank): what held back the logging of such high-frequency data was slow processing in current ANT+ head units. (The ANT+ protocol itself supports 256 Hz sampling.) Improved software, or perhaps a new head unit, should solve this.
“We like Michelin’s approach,” said Richard McAinsh. “It chimes with ours. Verve’s objective with InfoCrank was to build a power meter that’s accurate, reliable, and gives repeatable results. Really, it’s a precision instrument with a crankset built around it. That’s surprisingly hard to do.”
Watch the Michelin Pro4 video, showcasing some of their testing procedures, below.