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Wahoo Elemnt Bolt and Blue SC Speed Cadence sensor - wobbly readings

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Wahoo Elemnt Bolt and Blue SC Speed Cadence sensor - wobbly readings

Old 11-14-20, 01:33 AM
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takozukuri
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Wahoo Elemnt Bolt and Blue SC Speed Cadence sensor - wobbly readings

I've had my Elemnt Bolt for ~ 6 months and I have loved it. However, I recently added the Blue SC Speed and Cadence sensor and have had some change to readings.

Below is image from Strava on speed and estimated power for typical portion of ride prior to addition of speed and cadence sensor


Here is same chart for different ride but with the speed & cadence sensor.


With the sensor, a 15-mi portion of ride looks like this:


As you can see, speed now fluctuates (i.e. jumps up and down) on short term cycle. Is there a setting to smooth this out?
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Old 11-14-20, 02:08 PM
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Wahoo has had several issues with their BTLE connections since this pandemic started. There have been lots of complaints about sensors dropping and erratic behavior on the User's Group Forum. A solution that most have found is to make sure that your connection between the sensor and the Bolt is done via Ant+. Also, make sure that all the firmware is up to date, including the Blue SC sensor. You can use the Wahoo Utility to check and update the firmware on the sensor.

The best way to make an Ant+ connection (over BTLE) is to use a cycling app that supports BTLE sensors or the Wahoo Utility on your phone. If your sensor is connected to your Bolt via BTLE, un-pair it and pair it to your phone via the app. Make sure your phone is left ON. That will tie up the BTLE channel of the senor. From your Bolt, search for a new sensor, which will show the Blue SC and pair it.See if that helps solve the problem.
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Old 11-14-20, 03:52 PM
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Originally Posted by takozukuri View Post
As you can see, speed now fluctuates (i.e. jumps up and down) on short term cycle. Is there a setting to smooth this out?
I don't think you want to smooth this out. I think it means you have bad data. Smoothing it out is likely going to be a "garbage in = garbage out" exercise.

I'd change all the batteries in the sensors and, if it continues, take it up with Wahoo.

J.
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Old 11-17-20, 03:43 PM
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I too love my Wahoo Elemnt Bolt, and I also share your disapointment with the sensors. In the 6-8 months that I've been using the Wahoo Elemnt Bolt the heart rate sensor had to be replaced after about 4 month's and last week the cadence sensor died. Customer service has been excellent. Wahoo replaced the heart rate sensor under warranty, and they are also sending me a new cadence sensor under warranty. In both cases the battery inside the sensor died of natural causes and had to be replaced. As soon as the battery was replaced both sensors failed to return to normal function, which I found quite odd. They worked just fine until the battery died, so I have no idea why a new battery would cause any issues. And yes, I absolutely used the correct replacement battery. No "user error" on my part.

As for the Blue SC Speed and Cadence sensor specifically, it should work just fine since it's a Wahoo sensor. However, when I spoke with Wahoo tech support today about my failed cadence sensor I was told that milti-function sensors were known to be problematic. I assumed he meant third party multi-function sensors, but he didn't specify. It was a blanket statement. Now that I'm reading this thread it's possible he was including the Wahoo Blue SC Speed and Cadence sensor.

Wahoo tech support is very easy to reach and they are very helpful. Whether your sensor is under warranty or not I'd give Wahoo a call. 1 (877) 978-1112, and once in the automated menu press "3" for tech support.
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Old 11-17-20, 08:05 PM
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All of my cadence sensors are spiky -- both the earth induction types and older magnet based types that were ANT+ only. The averages are accurate but there are lots of spikes.

I see some occasional inaccuracies in speed, heart rate, etc., but nothing like the odd spikes in cadence sensors.
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Old 11-18-20, 02:14 AM
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Originally Posted by Cycletography View Post
I too love my Wahoo Elemnt Bolt, and I also share your disapointment with the sensors. In the 6-8 months that I've been using the Wahoo Elemnt Bolt the heart rate sensor had to be replaced after about 4 month's and last week the cadence sensor died. Customer service has been excellent. Wahoo replaced the heart rate sensor under warranty, and they are also sending me a new cadence sensor under warranty. In both cases the battery inside the sensor died of natural causes and had to be replaced. As soon as the battery was replaced both sensors failed to return to normal function, which I found quite odd. They worked just fine until the battery died, so I have no idea why a new battery would cause any issues. And yes, I absolutely used the correct replacement battery. No "user error" on my part.
I've had this happen with my Tickr, and resetting it by placing the battery in upside down for a few seconds has always fixed it. I'm surprised Wahoo didn't suggest you do so since the instructions are right there on the troubleshooting page.

Edit: in addition, you may have needed to unpair the sensor after changing the battery. That's also mentioned on the troubleshooting page.
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Old 11-18-20, 06:14 AM
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Originally Posted by surak View Post
I've had this happen with my Tickr, and resetting it by placing the battery in upside down for a few seconds has always fixed it. I'm surprised Wahoo didn't suggest you do so since the instructions are right there on the troubleshooting page.

Edit: in addition, you may have needed to unpair the sensor after changing the battery. That's also mentioned on the troubleshooting page.
Wahoo did have me do both things you suggested and neither fixed the issue for more than a day before malfunctioning again. So, as originally stated both the heart and cadence sensors did not return to proper funtion after the battery was replaced. Wahoo could never figure out why this same problem happened with both sensors. Tech support thought the most likely explanation was either a "bad batch" or the the sensors had sat in the warehouse for too long prior to sale. I'm not sure I buy either explanation. I can only assume (based on my experience) that quality control is not very good and/or the sensors are just cheaply built.

As for the head unit, it seems to be built like a tank. The other day I made the unfortunate mistake of leaving the Bolt in my shorts pocket when I did laundry. When I heard something rattling around in the dryer and found it was the bike computer my heart sank. I thought "oops, that's gonna be a costly mistake". However, when I pushed the power button it started up just like new. Also, there were no cracks, no scratches, no dents or dings, no exterior damage of any kind. The plastic cover for the charging port was pushed in all the way and it remained sealed throughout the wash cycle. It did its job quite well and I now have one more reason to love the Bolt. The Blot is extremely waterproof as long as the plastic port cover is securely in place.
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Old 12-20-20, 02:13 PM
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Thank you for the suggestions!

I tried all of the above suggestions (e.g. tried both BLTE and ANT+ signals, replaced batteries, updated firmware, sample rate could not be modified), and did not have any luck reducing the spikey-wikey readings.

I contacted wahoo and, as was mentioned by several responses in this thread and others, I had excellent experience with customer service. Mr. Sean C. was extremely professional, walked me through several potential fixes and in the end (when those did not work), provided me return instructions and refunded money (no hassle).
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Old 12-22-20, 08:53 AM
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I don't know why Wahoo still sells the Blue SC, seems like old tech to me with the magnets and all. Especially when they sell the wireless modules.

That Strava pic with the speed and cadence sensor looks plain wrong....the question is....is it Strava, or is it the sensor.
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