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Garmin vector 2s puzzled

Wilby_89Wilby_89 Posts: 96
edited August 2016 in Road general
I have had the vector 2s for a while and use them on my turbo or out riding everyday.
I have been cycling hard for about 2 years now and would say that I am very fit and weigh around 68kg and i am 5ft 8.
Anyway my average turbo session which is hard and last about an hour I would average about 250 watts this is based on a calibration test result of something like -0.12
I thought this was a bit low and have added one of the washers that came with them.
I now get a calibration result of +0.12-+0.25 and are average 280 watts doing the same workout.
I am very confused on which readings to take serious was wandering if anyone had the same issue or any advice.

Posts

  • Have you followed the installation instructions with regard to the number of washers required - the purpose of the washers is clearly stated and its down to you to determine how many are required - that said i think it probably suggests what the number that are usually needed for common cranks.

    Also, do you have the correct installation torque and are your vector angles/installation angles correctly set?

    I've got vector 1's, and while they can be a bit fiddly I've never come across such large measurement discrepancies. That said, how are you gauging your effort to say one workout gave you 250w ave and when you did it again you got 280w?
  • Wilby_89Wilby_89 Posts: 96
    Ive got a torque wrench and do it to the correct nm.
    im gauging my effort by doi g so much time in the exact gear at the same pedal rate 50x15 but at 92rpm withoutthe washer i get 245-265 with the washer 275-300.
  • imposter2.0imposter2.0 Posts: 11,003
    The best you can hope for is a number that is reliable and consistent. In that sense, why does it matter if you get a different number with/without the washer?
  • Wilby_89Wilby_89 Posts: 96
    Because I want to make sure my efforts are accurate.
    Here are the results from testing on the turbo this morning.

    WITHOUWASHER torque @40nm
    calibration result -0.16 to -0.12
    [email protected] rpm =139w

    WITHWASHER torque @40nm
    calibration result 0.16 to 0.09
    [email protected] rpm =150w

    What is going on.
    Without the washer I find my power is a lot lower riding climbs I can barley hold 300 watts and above.
    With washer if I'm smashing it I can stay within 300w-330w for a longer amount of time.

    Like I said I am very lean and healthy and have either been out riding or use the turbo trainer every single day for the last 2 years.
  • imposter2.0imposter2.0 Posts: 11,003
    Not sure if you're getting this or not. Your actual power is no different in either situation. One figure may be a closer representation of your actual power than the other figure, but it doesn't actually matter, providing that whichever number you use is reliable and consistent.

    I'll let you into a secret - the washers are not really giving you an extra 30 watts.
  • Wilby_89Wilby_89 Posts: 96
    Will what is then because I'm doing everything exactly the same.
    The reason why I want an ACCURATE reading is when I'm in group rides and we are riding to set watts if they say ride to 250 watts and my 250 watts is actually 230 watts then its not reliable.
    I understand what you mean riding by myself and getting an accurate consistent reading but is it a true representation of what I'm putting out.
  • imposter2.0imposter2.0 Posts: 11,003
    What kind of idiot would tell a group of individuals (presumably of varying fitness levels) to all ride to 250 watts ?? Maybe if they suggested riding at a percentage of FTP, then there wouldn't be a problem in the first place.
  • Also if you each weigh different amounts, 250W is going to translate as different effort profiles and different speeds for each rider.
  • on-yer-bikeon-yer-bike Posts: 2,974
    With v2 you only use washers to adjust the Q factor or to create clearance for the pod on some cranksets.
    Pegoretti
    Colnago
    Cervelo
    Campagnolo
  • buckmulliganbuckmulligan Posts: 1,031
    There are plenty of valid reasons for wanting accurate and not just repeatable power measurements e.g. if you want to use something like BestBikeSplit (or just plain old maths) to estimate target times on a particular course or climb, reverse-engineer CdA or even just estimate something basic like calorie burn.

    Using a PM properly requires 'knowing your numbers' reasonably well and it's bad practice to tool around with it reading 10 or 20% high because it will cause a lot of headaches when you want to switch PMs or use it for some calculations such as above.

    Although admittedly, prescribing a set power output for a group ride sounds like a questionable idea, not least because everyone's CdAs will likely vary significantly.
  • jgsijgsi Posts: 5,026
    Post on the Vector Garmin forum page... I am long term v1 user... that calibration does not seem to be ok.
    mine is usually 0.03 or even a zero.
    I never set angles 'on the road' by the way .. thats a job for the turbo.
    A simple calibration is ok though..
    Any issues I get...
    fresh batteries...
    and/or full installation again... careful tightening up of the pedal.. and if really necessary refresh via the Updater..
    You actually do NOT need to be OCD about the actual torque setting.. under do it you will get erroneous figures... over do it and you risk damage.
    I use a long handled for leverage and ease of use pedal spanner to tighten and never have issues...

    (You can set a manual offset in the software settings by the way for certain circumstances.)
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