Garmin 705 versus PowerTap Pro SL with ANT+

Roubaix Rider
Roubaix Rider Posts: 29
edited April 2009 in Workshop
I am thinking about getting a PowerTap, but it depends on its compatibility with the Garmin 705.

The 705 is, I understand, a much better 'computer' than the head unit from PowerTap (as a Garmin 305 Forerunner user, I'm minded to keep with the Garmin way anyhow).

So the first question is querying how compatible are the 705 and PowerTap? I understand with the ANT+ technology, they will talk, but how well will they talk...

For example, if I bought a Garmin 705 (with its own cadence sensor and HR strap), and a PowerTap Pro hub only (no head unit), would I then still need a PowerTap head unit, cadence sensor and HR strap or would they (the 705 head unit and PowerTap hub) 'talk' to each other fully?

If this is possible, who sells just the hub on their own (or laced into a Ksyrium Elite or Mavic Open Pro spec of wheel)? :?:

Comments

  • From what I have read the powertaps should communicate well with the Gamins.

    Try these guys for a powertap + wheel combo. I 've only heard good things about them

    http://www.cyclepowermeters.com/powertap-sl-wheel-only-476-p.asp
    17 Stone down to 12.5 now raring to get back on the bike!
  • willbevan
    willbevan Posts: 1,241
    Have not used the 705 yet with a PowerTap, thought I do have both (waiting to get the ANT+)

    I was actually shocked how basic the display of the PowerTap was, mind you having only ever used Garmin Forerunner 305 when i started running, and then a 705 when i broke it, i didn't have anything else to compare it with.

    I love my 705, if you want road mapping, more storage space for courses etc, or power meter integration then its a great piece of it, otherwise not much better than the 305 in my opinion, do love the advanced workouts for intervals etc :) (205/205/605/705 all have them lol)
    Road - BTwin Sport 2 16s
    MTB - Trek Fuel 80
    TT - Echelon

    http://www.rossonwye.cyclists.co.uk/
  • willbevan wrote:
    or power meter integration

    Will, does the 705 display power en route? If so, watt (sic) details are available to view...?
  • willbevan
    willbevan Posts: 1,241
    long time before a reply I realise, but after recieing a PowerTap Pro+ today, can confirm the powertap does display power while on route, also with the new 2.60 firmware for the 705, does not smooth the data before saving it
    Road - BTwin Sport 2 16s
    MTB - Trek Fuel 80
    TT - Echelon

    http://www.rossonwye.cyclists.co.uk/
  • graeme_s-2
    graeme_s-2 Posts: 3,382
    There's a video on YouTube with someone from Garmin demoing the Edge 705 setup with a power metre:

    http://www.youtube.com/watch?v=mNRGbTd2vhE
  • It may not smooth the data, but the Edge 705 STILL doesn't calculate power averages properly, it ignores stopped/no-pedalling times. If you want over high averages, then yes the Edge is the computer for you.

    I don't understand why Garmin can't get this calculation right :?

    Do any of you Powertap & Edge users get problems with breaks in communication between the Edge and the Powertap (i.e. the power goes to zero briefly)?
  • DaveyL
    DaveyL Posts: 5,167
    I presume when you upload the data from the 705 into WKO+ that it still works out the average Watts correctly though?
    Le Blaireau (1)
  • APIII
    APIII Posts: 2,010
    DaveyL wrote:
    I presume when you upload the data from the 705 into WKO+ that it still works out the average Watts correctly though?

    Yes it does
  • carbonfiend
    carbonfiend Posts: 475
    I'm thinking of doing exactly the same or a least getting a power tap, can any of you guys let me know if you think its worth it - ie do you feel your performance has improved and also has it taken any of the 'fun' out of cycling. 'm slightly worried I'll just become a 'power obsessive'. Any feedback suggestion etc would be appreciated.
    '..all the bad cats in the bad hats..'
  • DaveyL
    DaveyL Posts: 5,167
    Can anyone with the wireless PowerTap and Garmin 705 tell me what the 705 picks up in additon to power? The wireless PowerTap also gives speed and cadence from the hub, and there is a HR monitor strap. Does the 705 take speed from the PT hub or from its own GPS, and how about cadence and HR? Does it take them from the PT hub and Cycleops HR monitor strap respectively, or do you need the Garmin cadence and HR accessories?
    Le Blaireau (1)
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  • DaveyL
    DaveyL Posts: 5,167
    Thanks for the info - just wondering if it would be possible to get the 705 without speed/cadence sensor and have the Garmin pick that up from the PT hub. Seems like the HRM strap comes with all 705 models so that's not so much of an issue.

    I can see how the display lag could be annoying, but you need to get used to the way power is reported on the original PT head unit anyway - if you set the refresh to too brief an interval (1 or 2 s) then the readout is constantly changing, and if you increase it to 5 s or so, then I guess there will be a bit of lag too. It's only really on climbs that I've found you can maintain anything like a consistent power output - on the flat my readings tend to be all over the shop. I found a nice (in the "smooth data" sense of the word, not in the "pleasant experience" sense) section on my ride yesterday of about 8 km on a 2% false flat into the wind. I was doing a fairly consistent power all along that bit and when I looked at the data after in WKO+, it looked like a constant power effort I'd do on the turbo - for a 20 min period the variability index was 1.01!
    Le Blaireau (1)
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  • DaveyL
    DaveyL Posts: 5,167
    Hi Mark,

    If it isn't inconvenient for you, I'd be interested to see if the 705 picks up speed and cadence from the PT hub. I am toying with getting a 705, and would also have to fork out about £75 to update my (now relatively old) 2.4 SL hub to be ANT+ compatible, so any cost reductions would be useful!

    You can set the PT headunit to display a rolling average of power every 1, 2, 3, 5, 10 or 30 seconds. I have it set at 2s, though 3 might be OK too - every 1 s is far too jumpy. (It doesn't affect the actual recording of the data though, no matter what you set the display average to). Maybe there is similar on the 705?

    I am finding the PT quite interesting. I have used it so far only to work out my funtional threshold power, and to set zones from that. It's been good for doing turbo sessions at, say, tempo or threshold levels. I intend to use it for training, and also for pacing in TTs. For road rides I've been doing, I've just recorded the data and looked at it afterwards. WKO+ is pretty essential to get the best out of the PT, in my opinion. I have pulled the odd interesting bit out of some road rides - like the example above, and on one ride I rode for 105 min at about 15 Watts (normalised) higher than what I thought my FTP was, so it was back to the turbo for another test.

    I think for rides out on the road it will be quite tricky to stay in certain zones - since I'm quite a big guy, on any hills my power tends to go way over threshold. I have found though that it is quite useful for the other end of the spectrum as I've found that I can be riding along at a good endurance/tempo pace, and if my concentration slips, all of a sudden I'm tooling along at about 150 W and deep into my "active recovery" zone when I ought to be holding a stronger effort. So I think in that way it is good at helping you make sure you get the most out of your riding.

    I'll hopefully be doing some TTs in May so will see how it goes with pacing - at least one of them is pretty flat so it should be possible just to stick it slightly above threshold power and try and keep it there.

    The unfortunate thing is that I have been doing a fair amount of mountain biking this year and would be really interested in getting a MTB powertap as well, but there is no way I can justify the cost! It's just not the same, having to estimate TSS and IF after a ride :D
    Le Blaireau (1)
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  • DaveyL
    DaveyL Posts: 5,167
    Sure - take your time. Every time I check my bank balance I realise I'm in no hurry to get the 705!

    The PT should be very useful for pacing in sportives and the like so you don't go over threshold on the climbs. There's at least one user on here, bahzob, who used it to pace himself very successfully in the Marmotte last year and he also has a huge amount of experience in training with power.
    Le Blaireau (1)
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  • DaveyL
    DaveyL Posts: 5,167
    Hi Mark,

    That's great to know - thanks for running through that test.

    Hope your training with power is going well.

    Cheers

    Dave
    Le Blaireau (1)
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