PowerTap SL Problem/Question About HR

Discussion in 'Power Training' started by Tim Lamkin, Apr 9, 2006.

  1. Tim Lamkin

    Tim Lamkin New Member

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    Hope this has not been answered before, did a search cannot find anything about this specific issues.

    I am having dropouts in HR only ALL else is excellent. Will do the battery change wondering if these things consume bats at a higher rate?

    Watched if I was near or under power lines, never ride with anyone else so that is out.

    Has happened out side never in. Will try the foam on seat stay, however…..for my problem does not make a lot of since because the HR function goes from chest to receiver, so harnessing should have no effect on HR……or is my diagnoses of the harness and HR compatibility/inter-action flawed?
     
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  2. RapDaddyo

    RapDaddyo Active Member

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    The HR receiver on the PT computer chip sucks. I've replaced two PT computers (under warranty) for precisely this reason in the 10 months I have owned a PT SL. The only consolation is that after I learned to ride with power the only thing I use my HR data for is to illustrate to power newbies how inconsistent the power/HR relationship is. I haven't looked at HR in a ride file in 6 months. Call Saris and get them to send you a new computer. After you get the new computer, send back your current computer via 10th class mail.
     
  3. Tim Lamkin

    Tim Lamkin New Member

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    I agree on the HR data, however in my situation, we need the HR data for a bit more...hopefully only 3/6 months more.

    BTW I am an administrator on another forum (large one) you’re post are extremely helpful to both new members and old, you work here is to be commended.

    I will be calling them on Monday. I hope they respond quick.

    Do you think it is only coincidental that my problem happened when I went out side?
    One more question do these things eat bats at a higher rate then one might think.
     
  4. RapDaddyo

    RapDaddyo Active Member

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    Thanks.

    Same day, at least in my case. This is a known problem. I'm guessing it will be resolved with the SL2.4.


    That's peculiar. No explanation.


    Not really. I get ~4 months on a computer battery and I carry one in my jersey in the event I need to replace it during a long ride. BTW, I now have a 2nd computer as a backup. Eventually I'll have a backup wheel but I'm waiting for the SL2.4 hub to be released.
     
  5. Tim Lamkin

    Tim Lamkin New Member

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    I will now start planning on getting a back up also (hub) and go for a spare harness for trouble shooting too.

    Have you found any significant result or cause and effect of over tightening of zip ties on any part of the system.
     
  6. grom

    grom New Member

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    same deal with me today, the hr display dissapeared but was availaible via download maybe temperature/crappy road combo had something to do with it?
     
  7. RapDaddyo

    RapDaddyo Active Member

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    Yes, if you tie the receiver tightly to the frame, you may get hub transmission dropouts. This seems to be less of a problem with CF frames and maybe the new sharkfin receiver has solved the problem altogether. I eventually hung my receiver from the chainstay so it's not secured to the frame at all but rather hangs from it.
     
  8. palewin

    palewin New Member

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    With Spring coming, my experience may be "moot" but the hub batteries seem to last way less than the "advertised" 250 hours in cold weather. In NJ winter (temps 20-35F) they fail completely below 25F (no surprise, they just can't generate enough juice at that temperature, and Saris suggests 30F as a low-end threshold) but I was going through a set of hub batteries in about one month (~40-50 hours). Hopefully in warmer weather I'll be closer to the Saris numbers. My cpu batteries seem to last longer than advertised (they say 100 hours, I've been changing them around 120 'just to be safe').
     
  9. padawan

    padawan New Member

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    I've had the same experience. I'm sure RD is right that it's primarily the CPU HR receiver. But here are a few thoughts to help prevent 'some' of those HR drop-outs.

    First, in order for the receiver to work well it needs a strong and fairly constant signal from the chest strap (perhaps that's obvious). Riding inside most people tend to sweat more (unless you live quite far south and already have hot temperatures). More sweat, better conductivity. Cool, dry air, less sweat and conductivity. I don't use them but there are conductivity gel products you can buy to put on the chest strap. Just try to keep the strap REALLY moist. On cool outdoor rides when I've had a lot of HR drop-outs, I've sometimes gotten back, taken off my chest strap and found it quite dry. (Of course, maybe I just need to work harder) :D

    Second, you have to decide between comfort and function but cinching the chest stap a little tighter may help too. On an indoor ride, I don't move around quite so much. Outside where I'm shifting more and getting out of the saddle at times on hills, the pads for the chest strap may periodically pull away from your chest enough to cause loss of signal (especially if it's a little dry).

    Until Saris fixes the CPU problem, that's how I try to prevent drop-outs.
     
  10. RapDaddyo

    RapDaddyo Active Member

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    Maybe Saris should add this to their Technical FAQs. Q: What if my HR monitor is not picking up the HR signal? A: Work harder!:D
     
  11. Alex Simmons

    Alex Simmons Member

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    Well I did some threshold work outdoors this morning and I reckon I got the cleanest looking HR data I've had in some time, so maybe there is something in the "work harder" method! I don't get too many drops, mainly spikes. Drops are usually 'cause the chest strap sensor plates lose moisture/good contact. Had same problem with high end Polars HRMs.
     
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