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Vector 3 - Setting the install angles

NoPain666
over 7 years ago
We (Bikeboard.at) are just testing the Vector 3 and they work really fine. We did also some comparisons with other powermeters and with the Cyclus2 and the Vectors were showing accurate results. But one time, after installing on a different bike (with calibration afterwards), their watt values were too low. So I entered the "menu" on the Edge 520, went straight into "sensors" and "set installation angles". After setting them, the values seemed alright again.

On your homepage you write "Vector 3 and 3S: Install angles are automatically determined and set in the background and are not required to be set by the user."

My questions: Why is the function "Set Install Angles" still available on the Edge? What does happening after activating? And is it better to "set the install angles manually" after each new installation?

Thanks and best regards.
  • 0 over 7 years ago
    By how many watts or percent can the pedals potentially be off?
    And how long can it potentially take for the numbers to settle (both with and without resetting the angle)?
  • 0 over 7 years ago
    I figured that the best thing to do here was to illustrate how the power comes up after a pedal re-installation. My test setup includes a crank-based power meter (here called S1030), that is not affected by the pedal re-installation. The Vector 3 ANT channel is recorded as V510, and the Vector 3 BLE channel was recorded using an iPhone.

    The procedure was as follows:
    1. Ride for a few minutes to establish a baseline for the power reporting relationship between the two PM's.
    2. Remove the pedals, then insert the 2mm spacing washer, and reinstall. Because the pedal thread pitch is 1.27 mm (20 threads per inch), the 2mm spacing washer will cause about a 200 degree installation angle change, nearly the worst possible case.
    3. Do a manual zero calibration using the Edge.
    4. Ride until the power comes back up.

    You can see from the graph below, that the reference power meter comes back up at 1310 seconds. The BLE channel and ANT+ Vector channels come back at 1350 and 1367 seconds, respectively, and by 1376 seconds, the data from Vector 3 and the reference power meter are fully back in agreement. So the worst-case alignment time, when you are starting from a previous installation, is around one minute.

    The startup time when there is no installation history (i.e. when the installation angles have been reset by Edge command, or from first installation out of the box) will be substantially faster because the system is not trying to work against established statistics.

  • 0 over 7 years ago
    I'm unable to reset the install angles with my Garmin 810.

    This is being looked into.

  • 0 over 7 years ago
    I figured that the best thing to do here was to illustrate how the power comes up after a pedal re-installation. My test setup includes a crank-based power meter (here called S1030), that is not affected by the pedal re-installation. The Vector 3 ANT channel is recorded as V510, and the Vector 3 BLE channel was recorded using an iPhone.

    The procedure was as follows:
    1. Ride for a few minutes to establish a baseline for the power reporting relationship between the two PM's.
    2. Remove the pedals, then insert the 2mm spacing washer, and reinstall. Because the pedal thread pitch is 1.27 mm (20 threads per inch), the 2mm spacing washer will cause about a 200 degree installation angle change, nearly the worst possible case.
    3. Do a manual zero calibration using the Edge.
    4. Ride until the power comes back up.

    You can see from the graph below, that the reference power meter comes back up at 1310 seconds. The BLE channel and ANT+ Vector channels come back at 1350 and 1367 seconds, respectively, and by 1376 seconds, the data from Vector 3 and the reference power meter are fully back in agreement. So the worst-case alignment time, when you are starting from a previous installation, is around one minute.

    The startup time when there is no installation history (i.e. when the installation angles have been reset by Edge command, or from first installation out of the box) will be substantially faster because the system is not trying to work against established statistics.

    Thanks t_smit, that is very useful and interesting. So, if I understand correctly, you are saying that when swapping V3 from one bike to another, we will at worse lose 1 minute of data if we don't reset the installation angles.

    Incidentally, from the chart, it appears that the V3 is reading slightly higher than the crank PM initially and then, after re-installing with the washer, the V3 is reading slightly lower in comparison. Care to comment on that?
  • 0 over 7 years ago
    Incidentally, from the chart, it appears that the V3 is reading slightly higher than the crank PM initially and then, after re-installing with the washer, the V3 is reading slightly lower in comparison. Care to comment on that?


    The best practice for new installations is to tighten up the spindles, do a couple of hard sprints, and then re-do the zero offsets. I didn't get to the second part of the procedure in this test data set. It is not unexpected that the output will change a little bit as a function of installation angle but it should end up within the 1% range.
  • 0 over 7 years ago
    The installation angles are going to be fine at this point and you would be unlikely to see any substantial change from resetting them now.

    With Vector 3S your reported power will change as your balance shifts from left to right. This could well be different out on the road, compared to an indoor trainer environment.

    It’s possible that my balance outdoors is different from indoors. There’s perhaps as much as a 1% L/R inbalance indoors according to workouts I've done on various wattbikes. I wouldn't imagine outdoors wouldn't be too different TBH.

    My smart trainer along with 2 separate Wattbikes report 40w more watts than my Vector 3S at around my threshold power of 318w. At around 100w there is little or no discrepancy. As you might imagine this is playing havoc with my training. If the the problem isn't install angles, then what else could it be?
  • 0 over 7 years ago
    If the the problem isn't install angles, then what else could it be?


    It could be that at 318W, your right leg is pushing 180W and your left leg, 140. That would be a balance of 57/43 percent... quite a bit of bias but not at all physiologically impossible. If you want to unambiguously compare your Wattbike to Vector 3S, ride on your trainer and do 30 second to 1 minute single-leg efforts at some various intensities ranging from 100 to 200 watts. For the left leg efforts, Vector 3S will report double what it actually measures. So you would expect to see, for instance, 100W from your wattbike, and 200W from Vector 3S, for a left-leg-only interval.

    You can validate the force measurement accuracy from Vector 3S by hanging a weight from the toe loop of the pedal. To reasonably model the peak force application that you'd likely apply to get 320W at 90 RPM, you would have to use about a 65 pound weight so you would have to take some care from a safety perspective.

    I don't know how you validate the Wattbike's measurement accuracy.
  • 0 over 1 year ago

    Hi, I have been using a Vector 3 on my road bike since ages. My friend had a torque wrench handy, so we have finally torqued the pedals to factory recommended settings. The right one needed more adjustment. Now since this happened, my right pedal power readings are very low,  my left-right balance is way off (70-30 L/R), even after resetting installation angles (have ridden cca 220km). What should I do?

  • 0 over 1 year ago in reply to 8643223

    Have you calibrated the pedals?