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crank arm length and Favero Bepro

MACKANG
over 5 years ago

Hi.

Every time I power up my edge 530 and it connects to my Bepro pedals it will change the crank arm length to 180mm for both pedals ore even what you  see in the picture can happen. 180mm left pedal and 208mm for right pedal. I went back from fw3.50 to fw3.20 but the same happens. If I look at the sensor details on the edge it says 172.5, but when I connect the pedals to my desktop and run the bepro program it is chanced to 180mm every time. I have used the pedals with my edge 520 from December 2016 and never had this problem. I can't test it on my 520 any more because of a cracked screen, but if I test with my old edge 500 there is no problem with crank length.

I swore to my self not to by another gramin when I couldn't use my 520 any more, to bad I didn't listen. 

  • 0 over 5 years ago in reply to aweatherall

    If someone  has a contact at Favero or wants to direct them to this forum thread then please do so.

    I have looked at the messages that are sent and received between the Edge and pedals when they first communicate up to the point where the Edge gets the crank length and nothing appears to be wrong. This includes the set/get crank length message.

    Note that Edge is receive the crank length from the pedals and not sending it. As the crank length matches what it has the Edge does not send a set crank length message.

    In short the Edge in this case is not even trying to change the crank length.

    It looks like the pedals are internally messing up the crank length and that manually changing the crank length of the Edge forces them to be corrected.

  • +1 over 5 years ago in reply to aweatherall

    I have spent considerable time looking at this and I think I have an explanation for what is happening that matches what is being observed.

    To be able to confirm this I would need the ANT log from an older unit like the Edge 520 or the 1030 running build 6.30 that is paired to the BePro pedals.

    I believe that there are several things going on here. Some are on the BePro side and one is due to a change on the Edge side.

    From user observations we have seen that the left and right crank lengths can have different values (Left 180 mm, Right 208 mm)

    When first connecting to the BePro pedals the power data can appear to be wrong until the crank length is manually changed to another value and then set back to the correct value.

    The crank lengths being different is a BePro issue. The ANT spec and message only allow a single crank length value to be passed to the master pedal. The master pedal is the one that supports all communications with the head unit. The master pedal then communicates with the slave pedal over a private network that the Edge does not see or participate in.

    With the current Edge software release on the 1030 and 530/830 when it establishes communication with the pedals it does not change the crank length. It performs a get crank parameters and obtains the length. This length looks correct on the ANT message received by the Edge, but checking the lengths using the Favero tool shows that it has different crank lengths for left and right.

    The Edge then makes a get capabilities call to see if the head unit should update the crank length upon connection. This is the change that Garmin made to comply with the 5.0 version of the specification. The BePro pedals do not appear to have implemented support for this message type so the Edge does nothing.

    If you manually change the crank length on the Edge, then the length gets reset and everything is good.

    Prior to adding support for the capabilities message I believe that the Edge was always setting the crank length and was masking an issue that sometimes the crank lengths on the pedals are getting set to incorrect values.

    If the crank lengths were being correctly retained on the pedals, then you could change the length using the Favero tool or via the Edge when connected, and all would be good. Something appears to cause the stored crank length values on the pedals to get changed. It is not the Edge causing this as in the current software implementation is not sending a set crank length message at all, unless you manually change it.

    It appears that the older Edge software releases were masking a data issue on the BePro side by resetting the crank length upon each connection. Now that this is no longer the case the issue is surfacing.

    Ideally finding why the crank lengths are changing and fixing that would be part of the solution but implementing support for the capabilities message on the BePro pedals would put us back in the situation where it was getting reset every time the Edge and pedals established communication.

    To confirm this, I’m going to try and get hold of an ANT log from a 520 or a 1030 running build 6.30.

  • 0 over 5 years ago in reply to aweatherall

    Interesting findings my friend.

    We have the problem ! Now it's matter of which side will probably solve that issue in the software part.

    Garmin vs Favero. It could be a good idea to implement the way older software of 520 do to stay the crank length correct!

    Maybe favero should update the firmware.

    I wish I could help you with log but I don't own a Garmin 520.

  • 0 over 5 years ago in reply to aweatherall

    I really appreciate you doing this. I have not heard from Favero after I contacted them. I will write to the again and see if I get a respond.