Eratic Power (WATTS) Measurements
About
Spinner® Chrono™ Power March 16, 2018
In the last few weeks there have been a number of questions about the calibration process for
the Spinner® Chrono™ Power. Here are a few key points about the calibration process.
First thing to remember: The product provides a great balance between minimal service and
accuracy.
The Spinner® Chrono™ Power is calibrated at the factory, and automatically calibrates there-
after. No calibration task is required at the time of installation or as a periodic operation per-
formed by the facility staff.
Auto-calibration
Like any measurement system, the Spinner Chrono Power needs to reset the known zero
point. This is known as zero offset calibration. The Spinner bike will sense when the rider has
stopped pedaling, essentially when the RPMs are at zero. That’s when it will automatically per-
form this calibration. Customers who want to ensure the best power measurement are
advised to turn the resistance to knob fully to left to the off position (zero resistance) at the end
of every ride, and before pedaling begins again. This ensures there is no torque on the system
when the calibration is performed.
Wattage flux:
When a power meter is used for the first time, riders commonly comment that the wattage
measurement “appears jumpy”. This is NORMAL. There are constant deviations in the force
and velocity during every aspect of the rider’s pedal stroke. Given that the power meter meas-
urement is immediate, instantaneous wattage can appear to be jumpy, especially to riders
accustomed to training with heart rate or RPM, which tends to remain relatively steady.
Since it is normal to see this fluctuation, it is important to view wattage as more of a target
range rather than a direct aim. In fact, most instructors call out a wattage range for the riders to
aim for. When riders learn to manage their speed and pedal stroke technique along with appro-
priate resistance and cadence, variations in wattage measurements will decrease. Wattage
fluctuations are also decreased with proper body alignment on the bike and natural body move-
ment. Keeping an eye on wattage assists the rider in fine-tuning their riding skills to develop
sound performance on the bike.
Service:
Precor Service Technicians can perform service tests to troubleshoot the system, including
torque, WATTS, RPM, battery and generator voltage and amps, and display elements. If your
customer believes they have a bike with a Watts measurement issue, it may be caused by sev-
eral factors other than the measurement system itself. A service call will identify the cause and
a Precor service technician will be able to restore the bike to a fully functional condition. Be
sure to contact service@precor.com with any service needs.
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