In the world of cycling, accurate measurement of rider power is crucial for performance analysis, training optimization, and mechanical efficiency. Yet, no standardised method currently exists for quantifying the accuracy of bicycle power metres, making it challenging to evaluate performance and reliability across different systems. There is nothing like an independent review, especially when the reviewer’s own reputation is on the line. In 2023 Silverstone Sports Engineering Hub (SSEH) went on the hunt for a power metre good enough to ensure their own Pedalling Efficiency Rig could meet their customer’s needs. They loved our power metre and have been kind enough to share their results with us, which we’re sharing with you here.
SSEH conducted tests comparing the Body Rocket system against both a high-quality commercially available ANT+ power metre and their reference dynamometer. These results shed light on our system's accuracy, reliability, and repeatability in real-world conditions. Below, we break down each plot from the tests and discuss the significance of these findings in the context of power measurement technology.
Statement from SSE: "Silverstone Sports Engineering Hub have chosen to the use Body Rocket system for rider input power measurements on their Pedalling Efficiency Rig, as no other power metre could offer the precision and wireless data logging capabilities required for a high-performance R&D tool to analyse mechanical and human performance, combining two unique ground-breaking products in cycling technology and development."
Currently, no standardised method exists for quantifying the accuracy of bicycle power metres. Therefore, rather than presenting proprietary data, we are sharing a series of plots generated by the Silverstone Sports Engineering Hub, comparing the performance of our pedal system against their reference dynamometer and a high-quality commercially available ANT+ power meter. This assessment provides an objective evaluation of our pedals' measurement accuracy and reliability.
Plot 1 provides a detailed comparison between the Body Rocket system (input power average), a high-quality commercially available power metre (ANT+ power), and Silverstone’s reference dynamometer (output power average). The gap observed between the Body Rocket and reference dynamometer values quantifies power losses attributable to drivetrain and rear tire inefficiencies. Given that both Body Rocket and ANT+ power represent measures of input power, their readings should align closely.
Plot 2 presents three repetitions of a tire pressure test conducted on Silverstone’s Pedalling Efficiency Rig, with Body Rocket data represented in blue and the commercial power metre data in orange. The two primary conclusions are as follows: (1) The Body Rocket system demonstrates significantly higher repeatability compared to the ANT+ power metre, and (2) based on this data, the Body Rocket system stands out from other ANT+ power metres, offering a distinctly higher level of precision and performance.
We would also like to clarify our response to a recent webinar question regarding the use of non-round chainrings: While we have not yet conducted tests with non-round chainrings, we anticipate to have no issues. Some power metres encounter difficulties with non-round chainrings due to their assumption of a constant rotational velocity throughout the pedal stroke. In contrast, the Body Rocket system continuously monitors rotational velocity throughout the pedal stroke, making it well-suited to accommodate the increased velocity variations introduced by non-round chainrings.
