Early adopter woes

Oct 1 I ordered the ANT+ updater for my PowerTap MTB hub.  This gizmo upgrades the firmware in the hub such that it transmits on 2 channels:  1 to the power tap computer head, the other channel on ANT+ sport.  The ANT+ channel is a semi-open protocol and several devices speak the language.  Among them in Garmin’s Edge 705.

 I picked up a 705 after this years Canadian affair in which I left behind another GPS unit – doh!  The 705 had already caught my eye though because it is ANT+ and would eventually be able to communicate with power transmitting hubs/cranks.

 The ANT+ updater arrived last weekend – the update was fast and easy, with a few other wrinkles though – I’ll have those details up on lwcoaching.com eventually.  Once updated, the 705 picked up the PT signal immediately – bingo!

Yet…it is not as simple as it seems.  The 705 uses an (unknown to me) algorithm to smooth the raw recorded data and in the process the integrity of that data is gone.  It baffles me why they take a quality raw data stream and alter it!  It essentially takes the good stuff and turns it into less good stuff.  It’s really a bigger issue with variable efforts such as occur in road racing and single speed MTBing.  Steady endurance rides would probably come out similar.  It scrubs about 30% of L6 power from every one of my SS files when compared to the PT CPU.

So heads up y’all.  Gizmo integration is just around the corner but ain’t here yet.  If you want a 705 to go with your PM it’s best to hold off for now.  If you’ve spent $1,500 on your sweet power meter you probably want it to record good data and for now that means stick with the PT CPU in the powertap system.

10 replies on “Early adopter woes”

  1. Crap. Guess I’m hanging onto my wired tap for awhile longer then. Technological evolution is tedious. Maybe if I wait just a little longer they’ll integrate the I-phone with the 705, fix the Garmin, create a real users manual, and give me some wireless coverage here in the boonies. Thanks for the heads up.

  2. DH, have you emailed garmin to see if there is a hideden smoothing setting somewhere in the 705 that you can edit? What software are you suing to pull the data file from the 705? Have you tried pulling the data file with a different tool?

  3. Dave – tons of details I haven’t put in this post….

    I’m using TopoFusion, GTC, and WKO, and straight off the 705 in windows explorer.

    Garmin has known about this for a long, long time. Slipstream used the Garmin/PT combo in the tour this year (and surely other events). During that time Saris contacted Garmin about the smooting of the raw data, and their initial response was that the smoothing was done at the request of ANT+ consortium members. They have not yet fixed it but have know for at least 1/2 year it is not satisfactory, during which time at least one (maybe 2) firmware upgrades have come out for the edge.

    Go here for more beta and a few pics: http://groups.google.com/group/wattage/browse_thread/thread/aa2d92c4e8b1c4b7?hl=en

    You’ll need to join if you haven’t yet.

  4. Uhh, how about when your legs hurt you are going hard, when they don’t you are not – seems to mostly work for me and I don’t have to learn a whole new language…and buy expensive gizmos to lose or break.

  5. Hi Dave,

    I too have the 705 and I’ve noticed that the heart rate display gets goofy. I was wondering if you had a main contact at Garmin you are working with.

    All of the call center people are helpful, but it seems like the some issues are outside of their training.

  6. Hi Bruce,

    I’ve had some contact with David Downey, mostly via the wattage forum. I think he’s the lead programmer for 705 functionality but that’s just a guess.

    FYI the latest is that he’s acknowledged the raw power pre-filter and now understands that it needs to be removed. I don’t know when that will be…but it will make the PT-garmin combo much better.

Comments are closed.