SB20 - Power Meter Failure

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The SB20 has two crank-based Power Meters (PMs). They are battery operated and provide power data to the SB20 Bike itself. The left power meter can also be configured to send information directly to apps like Zwift.

How to Isolate Failures 

Power meters can become less accurate over time. They can also fail outright.

Isolating failures is important. Dead power meters can stop your SB20 from working.  On the other hand, a single functioning PM allows your SB20 work perfectly with only a few limitations. 

Here are the most common scenarios:
  1. My bike has no resistance or inconsistent resistance that goes up and down randomly. This happens when you first power up and start riding, or when using an app like Zwift.  This is not a PM failure.  See SB20 - Resistance Failure.
     
  2. Both Power Meters consume batteries in a few hours of riding. This is rarely a PM failure.  Both PM rarely - if ever - fail together at the exact same time. This problem is more likely caused by bad batteries.  Counterfeit CR2032 cells are very common - especially when purchased on Amazon. Try this: Stages Power Meter Battery Tips

  3. Power readings are low, high or inconsistent.  Data dropouts occur frequently. My speed in Zwift is erratic or stops altogether. This suggests that a PM has failed, so keep reading.
How to Isolate a Single PM failure?

Finding one bad PM is easy.  Here is the procedure:
  1. Remove battery from the PM that you think is bad. Left or right. It does not matter. Turn bike power off / on. Connect to the Stages Bike in Zwift for Cadence, Power Source and Resistance*.  You can also just start riding in the Stages Cycling app. If everything now works, this PM is bad.

  2. Put the first PM battery back and remove the battery from the other PM. Turn bike power off / on. Connect to the Stages Bike in Zwift for Cadence, Power Source and Resistance*, or do a ride in the Stages Cycling app. If everything now works, this PM is bad.
 
*When you connect to the Stages Bike for Cadence, Power Source and Resistance or use the Stages Cycling app, the SB20 automatically compensates for a missing PM. 


How to Fix 

When a single PM failure has been isolated, see SB20 - One of my Power Meter Cranks Have Failed. Now What?  

If you think both PMs have failed, see SB20 - Both Power Meter Cranks have Failed - Now What? 

Other Possible Fixes









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