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PowerTap P1 bug. Left pedal getting wrong cadence
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Hello folks,

Bought a pair of P1 pedals just after its release, on august 2015. Didn't use until 2016 for personal problems. Since then I have rode only something like 10k km on then, swapping between my road and my TT bike. Never had any issue until last thursday, my last final ride on them.

Yesterday I went for a ride and quickly realise something was wrong. Cadence was off what I perceive and power way too high. Then, cadence dropped to about half what I was doing and power drop to almost zero. Removed from my garmin edge 520, calibrated again, stopped and waited until the pedals went to sleep mode, nothing. Stoped my ride and came back home.

Moved to my TT bike on the trainer, changed batteries (that was still good) and updated the firmware.

Then, tried again. Still not working.

So for some reason I started to ride using the PowerTap app for iphone. A message saying that my left pedal was not connected to my right pedal was showed Odd. The message also said that this would be ok if I use with bluetooth, but not ok to use via ANT+. I clicked to connect both. All good.

Tried again and still not working.

I then opened each pedal individually within the app and I saw that my right pedal was showing cadence and power numbers correct. But when I went to check the left pedal, cadence was WRONG. About half or less of what actually was happening. I can make an educated guess that for that reason, power numbers wont be right, even thought the right pedal was ok. I also checked the crank arm lenght.

So I kept pedalling while watching the dashboard of PowerTap app. After some 45 seconds the cadence from the left side was spot on again, and the power numbers jumped for what I know is the right number. So I kept pedalling more 3 minutes and everything was fine. I did one leg drills and the balance was right, the cadence was right. Oh god, it was a relieve.

But unfortunately, yesterday I was preparing my stuff and went for a lap inside my building garage and, for my absolute sadness, same problem again. I Opened Rouvy on my android phone and the left pedal was showing wrong cadence numbers again.

Tried everything again, but this time with no sucess.

Here a few videos I recorded:

1)
2)
3)

The main problem is that the warranty has expired and I live overseas, so send it over to Saris is gonna be a PITA.

Please, any magical answer to that? Especially considering that after the initial problem it came to life for a moment.

Thank you in advance and sorry for the long post.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [binhopires] [ In reply to ]
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Have you checked the firmware is up to date?? Given the age of the pedals you could be on a very old firmware version.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [cgrubb] [ In reply to ]
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Yes, they are. As seen on the first video.
=(
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [binhopires] [ In reply to ]
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I like my P1s, but these old gals (first couple of production runs) can be temperamental. Mine have been back to Saris twice, and still suffer from occasional split brain syndrome where the left (master) pedal will lose connection with the right, and I only get half my power. This will last for half a minute or so and then resolve itself. This usually happens with not-quite-new batteries, and it doesn't happen with brand new ones. The result is that I usually replace my batteries when the app says they're still 75%-80% full.

Anyway, all this to say is that you may be SOL, since yours are early models as well.

Citizen of the world, former drunkard. Resident Traumatic Brain Injury advocate.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [Richard Blaine] [ In reply to ]
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For what I'm seeing, there no "cadence sensor" inside the pedals. It's look like they calculate it from angular velocity.

This being said, I think it's the end of the road =(
Unreal, 10-11k km for a 1.2k usd item.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [binhopires] [ In reply to ]
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binhopires wrote:
For what I'm seeing, there no "cadence sensor" inside the pedals. It's look like they calculate it from angular velocity.

This being said, I think it's the end of the road =(
Unreal, 10-11k km for a 1.2k usd item.

Yeah, that sucks. But you have options. Have you called Powertap to see if they'll do anything for you? The pedals are 799usd, now. And if you joined the circa list and got Dan's offer, they're 639usd.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [binhopires] [ In reply to ]
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Did you replace the batteries with legit lithium batteries? It truly makes a difference.

Otherwise, even though they are out of warranty, Saris will still offer troubleshooting, but don't be surprised if the final verdict is send them in for service...which will cost $.
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Re: PowerTap P1 bug. Left pedal getting wrong cadence [FatandSlow] [ In reply to ]
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FatandSlow wrote:
binhopires wrote:
For what I'm seeing, there no "cadence sensor" inside the pedals. It's look like they calculate it from angular velocity.

This being said, I think it's the end of the road =(
Unreal, 10-11k km for a 1.2k usd item.


Yeah, that sucks. But you have options. Have you called Powertap to see if they'll do anything for you? The pedals are 799usd, now. And if you joined the circa list and got Dan's offer, they're 639usd.

The OP is part of the email I sent them 2 days ago. Still no answer, which is unacceptable IMO. If they dont answer today, I'll have to call.
What do you mean by Dan's offer?

dfroelich wrote:
Did you replace the batteries with legit lithium batteries? It truly makes a difference.

Otherwise, even though they are out of warranty, Saris will still offer troubleshooting, but don't be surprised if the final verdict is send them in for service...which will cost $.

Yeah, I'm using Energizer Lithium. Tried 3 different actually.
I think now I have my mind at ease with the fact that I'll be riding the gym stationary for a while. Put my focus on swim and run while this pedal make a travel
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