I have no idea what the true reader base of my blog is or how “powerful” it is.  I know I get about 50 unique visitors per day, so I thought I would the word about an issue I’ve been having with my Cycleops Cervo computer – aka Little Yellow Computer (LYC).

Mine is running firmware 7.6, and while on the bike all the metrics I watch: Power, Cadence, Time all display correctly.  Distance is wildly off and I have to use a crazy rollout (2033 for a 2096) wheel to get distance to measure close to accurately.

The bigger issue becomes appearant when you download.  Once downloaded into WKO+ or Poweragent, it inflates the actual ride time by about 1 mintue per hour.  As the ride get’s longer, the inflation get’s bigger.  1 minute for a 1 hour ride, but 7 to 8 minutes for a 5.5 hour ride.

The issue is definately within the LYC – you can verify this by looking at the average speed displayed on the computer itself.  If you take the distance and divide it by the time, you can an average speed that does not match the average speed displayed.  BUT if you take the distance and divide it by the “inflated” time – you get the displayed average.

Confused yet?

The Joule does not display this issue.

I’ve detailed a lot of my tests in the following thread on slowtwitch: Powertap LYC Issues Thread.

If you have issues similar to this, please contact Saris and make noise.  If they give you crazy talk – please leave a comment or use the contact page to give me your contact info, and I’ll periodically update my contact at Saris with people who are having the issue and/or an impression of people impacted!!!

2 thoughts on “Powertap Computer Issues

  1. I’ve called Saris to ask about a “bug” and have been told to reinstall PowerAgent and then try to run a firmware update. Unfortunately, I have 7.6 on mine as well and I still have this glitch… I have 2 CPUs and each miscalculate total time… I am wondering if therefore the NP for an effort might also be miscalculated if the time is off? I’ll call them again and see what they have to say.

    • I have a friend at saris that I’ve been working on with this. He’s gotten some info back from the software devs about the issue – I need to give him a call to get an update on what he’s learned. I’ll give him a call tomorrow.

      From what I’ve read and experienced I’m 100% convinced it’s a FW issue in the LYC.

      Will reply tomorrow evening – if I am able to get in touch with him.


      P.S. I think the power data is pretty accurate, although you are right NP could be a bit skewed – but probably not a TON. My biggest concern is that I’d like to be able to fix files that have already been screwed up – but I don’t think that will happen.

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