A US patent application has been just published that suggests a power meter could be on the way from Campagnolo.
We told you back in December that Campagnolo could be planning to add a power meter to its range after we spotted a US patent application for a wake mechanism to switch an electronic device from standby mode to running mode. Campagnolo said that the electronic device in question could be a crank-based power meter.
We also told you that Campagnolo filed patents relating to power measurement back in 2019 when engineer Keith Wakeham was working with the brand. Wakeham is currently CEO of cycling electronics company Titan Lab and worked on power meters for 4iiii in the past.
One European patent application was for a ‘Bicycle crank arm on the transmission side, provided with stress/strain detector for a torque meter or a power meter’. This invention relates to composite cranks with a detector housed internally.
Another patent application shows a rechargeable battery cell in the face of a crank arm body. The chainset is equipped with an electronic “detection system [that] can be used in a torque meter or in a power meter”.
Now a US patent application has been published for a ‘bicycle component provided with a temperature-compensated stress/strain sensor’. It is very similar to the European patent mentioned above, although it was filed in December 2021. Although the language is convoluted, the product in question is certainly a power meter.
Campagnolo says, “What is claimed is a bicycle crank arm comprising a main body extending along a lengthwise direction between a rotation axis and a pedal axis, the main body being made at least in part of a composite material comprising structural fibres that are incorporated in a polymeric matrix
“At least a first stress/strain sensor, supported by said body and aligned according to a direction of stress/strain to be detected and at least a first temperature sensor supported by said main body and associated with said sense stress/strain sensor were in said first stress/strain sensor and said first temperature sensor reside in non-parallel non-coincident planes.”
Yep, convoluted. That’s the world of patents for you.
As usual, Campagnolo outlines many possible designs, but in plain English, the thrust is that the device relies on strain gauges attached to the crank arms of a chainset. The strain gauges could be fixed to the outside or in a cavity in a hollow crank arm. Temperature sensors – preferably thermistors – are included, “improving the reliability of the temperature-compensated stress/strain measurement”.
In one version of the crank arm, “the main body forms a shell extending around a cavity [that houses] one of the first stress/strain sensor
and the first temperature sensor applied to an inner surface of the shell.”
Campagnolo says, “The crank arm manufacturing process comprises the step of providing a core of a predetermined shape, applying said stress/strain sensor and said temperature sensor to the core and covering the component being processed with the composite material, so as to create a crank arm in which the composite material is in the form of a shell or cladding.
“A ‘cord’ of composite material preferably comprising substantially unidirectional structural fibre is positioned in the recess [of the crank arm]… wherein the direction of the unidirectional fibre is substantially aligned with the length… of the crank arm. The cord can be formed of one of more rolled up plies of composite material, or it can comprise a braid or similar of dry unidirectional fibre which is impregnated with polymeric material prior to the insertion in a mould, or impregnated with polymeric material during holding.”
In other words, the device is well integrated into the design of the crank arm in this version rather than simply being added to an existing model.
The patent application covers various crank arm designs, including one where the two crank arms are each made as a single piece with a spindle element, the two spindle elements attaching end-to-end – as they do with Campagnolo’s existing Super Torque system, for example.
All of the measurement occurs at the crank arms. Campagnolo doesn’t mention options for other sites of measurement such as pedals, spider, or chainset spindle.
Of course, this doesn’t necessarily mean that Campagnolo is going to produce a power meter imminently. Loads of patents applications are made – and patents granted – for products that never make it off the drawing board. We’d say, though, that Campag can’t be satisfied with its groupset customers needing to go to third-party products for power measurement, so this one is a distinct possibility.
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.