Power meter from Pioneer in the TOUR test - Pioneer Cyclo-Sphere and power meters in check

There is room in the smallest niche: this may be the reason why the global electronics company Pioneer has taken on the topic of power meters - even though it can certainly sell far fewer of them than flat-screen TVs. In 2013, Pioneer launched the first version of its power meter on the market, followed by the second in 2015, which was available for us to test for almost three months.

The highlight of the system is that you can see how you are pedalling while riding - separately for the right and left leg. This allows athletes who are keen to experiment and already have experience with power meters to not only control their training but also to evaluate their pedalling movements in detail and possibly optimise them - possibly because new data also raises new questions, which will be discussed below.

The system, which only works with metal cranks, consists of sensors for the left and right cranks (€1,400 per pair) and a bike computer with a touch-sensitive display (€300).

WHAT THE NEW ONE FROM PIONEER CAN DO

The functional principle is not new and is also used in other powermeters: Strain gauges, which in the case of Pioneer are attached to the inside of the crank arms. When the cyclist pedals, the crank "bends" - experts call this elongation - which is invisible to the eye. However, this can be measured using sensitive sensors that detect this material elongation in two directions: tangentially to the crank and radially in the direction of the crank arm. The total force can be determined separately for each crank from both components and the direction in which the forces act in the course of a crank rotation can be visualised. Every 30 degrees - corresponding to the hour increments on a clock face - the handlebar computer (or the software when analysing the data later on the computer) displays the forces as arrows. The system collects more information than the ANT+ radio standard can process, which is why only the associated Pioneer computer can display the full range of information. However, the crank sensors can also be converted to the normal ANT+ standard and are then compatible with handlebar computers that also use this wireless standard.

MOUNT AND ADJUST

Together, the sensors weigh just 66 grams and can currently only be combined with Shimano's current Ultegra and Dura-Ace cranks (FC-6800 and FC-9000). You can either retrofit your own cranks, which you have to send to Pioneer via a dealer, or you can buy them in a package with Shimano cranks. Important: There must be enough space between the left crank and the chainstay for the 9 millimetre high sensor to fit through.

The installation of the sensor-equipped cranks and both crank magnets is fiddly; you have to follow a precisely defined procedure. The so-called temperature compensation is also not factory-fitted, but must first be learnt: To do this, you have to "zero" the system at as different temperatures as possible, which in practice means getting off the bike during the ride and pressing buttons. This is necessary because temperature jumps, for example on a descent, can cause tension in the metal of the crank, which distorts the result of the strain gauges. As part of the temperature compensation, the computer saves correction values and adjusts the measurement result. Once set up, however, the system is relatively easy to operate. The cranking batteries are easy to replace and Pioneer gives the CR-2032 batteries a service life of 180 hours.

THE STEERING COMPUTER

The compact computer is double-locked in the supplied handlebar mount and is ideally positioned in the field of vision. Barometric altitude measurement and GPS reception for recording the route (not for navigation) are on board. The display can be extensively configured - up to nine data fields can be displayed on each of six screen pages. Operation is largely self-explanatory thanks to plain text menus and is carried out via the screen, which responds to pressure and swiping. There are also three buttons on the side of the housing.

The touchscreen is easy to use as long as you can concentrate on it; the display backlight activates automatically. During the 25 test drives, however, the computer logged off twice in the middle of the journey for no reason. When driving through the forest, the GPS module also occasionally lost satellite reception - as a result, the automatic start-stop system registered a standstill at full speed and stopped recording data. An additional speed sensor is therefore recommended. The battery life of the 74 gram computer of twelve hours is rather short, but the internal memory collects three gigabytes of data, which is pleasingly large. A professional could use this to record their training for at least three years.

Data recording is activated by starting and stopping the watch. After the ride, the bike computer uploads the data directly to www.cyclo-sphere.com via WLAN - which is very practical.

UNEQUAL LEGS

Analysing the pedalling movement and showing it on the display quickly becomes the most frequently used feature because it gives the cyclist precise feedback on how they are currently pedalling: force vectors illustrate the power of both legs individually as arrows; additional key figures evaluate the efficiency of the left and right leg; the overall power is also displayed. If you change your pedalling style while riding, it is difficult to tell from the power arrows; the efficiency indicator shows it more clearly. Pioneer defines "efficiency" as the ratio of tangential forces to total force and rates a high proportion of tangential forces as positive. Consequently, the efficiency index improves when the ankle is moved through the lower and upper reversal points of the crank (the dead centres) or the leg is actively pulled upwards during the upward movement. The measuring system therefore helps you to precisely analyse your own pedalling movement. You can see how you are pedalling and can therefore make targeted changes to your pedalling.

AND - IS IT ANY GOOD?

Whether this conscious pedalling control opens up a new dimension of training is not so easy to judge. Efficiency is also influenced by whether you pedal quickly or slowly or with a lot or little force. This means that a high efficiency figure does not necessarily make you faster. Furthermore, the definition of efficiency in the Pioneer calculations is not free of errors. In the upper and lower reversal points of the crank, inertial forces act due to the reversal of movement of the legs. Compensating for this with active, additional muscle work improves efficiency, but is not sensible because this force does not generate propulsion - it would be a waste of energy. Training science does not yet have an answer as to whether and how the efficiency indicator can be used for training. The Caloped system, which has been used in the rehabilitation sector for many years, follows a more advanced approach because it not only displays the forces on the pedal, but also the muscle work of the legs - which actually needs to be optimised. Unfortunately, this is not available for use in road racing bikes.

The data can be analysed in the Pioneer cloud in the browser and exported to other platforms such as Strava or Trainingpeaks. The free Pioneer platform offers a wealth of options for analysing the data and is sufficiently fast. What's impressive is that you can visualise pedalling power and torque for each point of the ride and see where it was on the map and in the ride log. However, individual data points are not as important for the analysis as higher-level functions that visualise correlations.

In total, the data can be displayed in nine different graph versions, which fulfil many, but not all, analysis requirements. Experienced users will probably maintain the data on at least one other familiar system in order to complete the training documentation, save intervals and do other things that the Pioneer software does not yet allow. For example, there is currently no comment function for training.

FOR ENTHUSIASTS

However, one thing is clear: Pioneer is bringing movement to the market for performance measurement devices. Additional data opens up new possibilities for training - but processing it is becoming increasingly complex, and the interpretation of the new data types is still in its infancy. It is therefore primarily up to sports science to develop the right analytical approaches for the new flood of data.

PLUS Left-right resolution; footfall display; software; WLAN
MINUS GPS dropouts; computer dropouts; short battery life of the computer; two frame magnets required

INTERVIEW: "Cyclists can train better than any other endurance athlete thanks to the power meter"

TOUR What are your most important parameters for training control with power meters?
VAN ERP The training load, calculated from the performance data, time in training zones, sprint and interval values. Training is based on watts, but I also look at the heart rate to get additional information on fatigue. With a power meter, cyclists can train with enormous precision - better than in any other endurance sport.

TOUR What are the benefits of left-right measurement with the Pionier power meter?
VAN ERP At the moment, we mainly use them to monitor the recovery and build-up process after injuries. We are not currently doing anything about a two or three per cent difference that a rider has had for many years. You also have to be careful with the changes in the pros. If we find major discrepancies, we first go to our physiotherapists to investigate the causes.

TOUR What are the efficiency values of the professionals?
VAN ERP The average value is 40%, at very low pedalling power the values can drop to 25%. At higher power, the values increase and are then 60-70%.

The new diversity

The market for power meters is growing steadily. Prices for entry-level devices are falling and differentiation is increasing. Almost all devices work with the ANT+ wireless standard and communicate with a large number of compatible computers.

Measurement in the crank star

Classic principle invented and patented by SRM, whose patent protection has expired. Robust, tried and tested, measures total power, but cannot resolve left and right exactly.

Measurement in the crank arm

The measuring principle requires metallic cranks and allows exact left-right measurement. As an economy solution, there is the one-sided measurement in which the measured value is multiplied by two.

Measurement in the pedal

The measuring principle allows exact left-right measurement. Optionally, only one leg is measured and the value is multiplied by two

Measurement in the hub