SRM and Garmin Edge 800 - incorrect slope and offset

Discuss light weight issues concerning road bikes & parts.
djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

Currently my Edge 800 is having some difficulties with my wireless SRM.

It seems that the Edge will all of a sudden set the zero offset value ("Calibrate") to some random number which is way too high, I will then have to re-calibrate/reset the offset manually through the menus.

At this point the slope is also changed to a random number, after I've corrected the offset, and typically to an outlandish 20-digit number.

Has anyone experienced things like this? What's been the solution?

by Weenie


wetpaint
Posts: 82
Joined: Sat Feb 06, 2010 2:55 am
Location: USA

by wetpaint

I haven't ever experienced either of those issues. Does your 800 have the latest firmare installed, or do you have access to another Garmin or a Powercontrol? That way you could test and see if it is the Garmin or the SRM itself causing the problems.

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

I would think it is not the SRM causing the problems. The offset value has to be set manually, the SRM itself does not know its offset. As goes for the zero value, it has to be set manually (or through the Edge's auto function).

It seems the problem is acute in cold weather. It has yet to happen in warmer weather I believe. Perhaps there is a problem with moisture in the Edge.

At first I thought there was corrosion on the USB connector, however in sufficient lighting it appears to be just a little bit of wear from the USB plug having been attached/detached a number of times.

My Edge does not have the latest firmware. I will check my version, read the changelogs from Garmin and consider if an upgrade is needed. I won't upgrade unless Garmin has specifically addressed such an issue, I guess. The risk of the Garmin just contracting more new diseases is too great with these firmware updates... especially as regards powermeters.


Addendum: The Edge IS running the latest firmware, so I guess old firmware problems can be ruled out (however new ones can't)

audiophilitis
Posts: 509
Joined: Sun Jul 29, 2012 12:49 am

by audiophilitis

Somewhat off-topic but has anyone heard of rumors on a new Garmin model? The 800 has been their flagship model for a few years now.

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

Heard rumours, maybe in the spring?

Watch the DC Rainmaker blog for news I guess... Seems to be Garmin's more or less unofficial official product blog ;-)

Still noone experiencing the same?

I'll try and see if I experience the same problems with a friend's unit. However it seems the problem occurs both indoors in high/normal temperature aswell as outdoors in the cold.

timzcat
Posts: 315
Joined: Thu Sep 30, 2010 5:50 am

by timzcat

Garmin 800 in general. I have had my Garmin do crazy things when I let the activities build up and don't delete them. Presumably it gets low on free space (internal) and acts up.
I would start with cleaning up activities and courses and see if it makes a difference.

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

Thanks for that tip.. I will try it out. There's definitely quite a few activites saved on it :-)

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

Cleared the internal storage for all activities, and the problem is still there. The slope is rendered to a 20-digit number almost every time I set the zero offset..

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ms6073
Posts: 2372
Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

A couple suggestions, un-pair/re-pair your SRM, alternately, do a hard reset on the Garmin, finally, if possible use a SRM PCVI/7 as a cross reference to verify the actual slope/zero-offset values.
Michael - The Anaerobic Threshold is neither...

JacktheHat
Posts: 1
Joined: Wed Feb 17, 2010 1:33 pm

by JacktheHat

Just wondered if this problem was ever solved? Am having the exact same issue with my edge 800 and SRM. When I set the zero offset the slope changes to some random insanely long number and the power is way off.

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

I changed Garmins and the problem is still present, it is still an 800 with the same firmware, and I have yet to try it out with, say, a 500. Seems like there is something wrong with the SRM if the problem persists with a 500. However the power readings are good once I correct the slope. Sometimes lately when the unit has auto-set the offset the slope has remained correct.

nurseflash
Posts: 7
Joined: Sat May 11, 2013 4:18 am

by nurseflash

Garmin just released new firmware. That may help.

djm
Posts: 1403
Joined: Thu May 14, 2009 12:19 pm
Location: Norway

by djm

nurseflash: Thanks for the tip!

I installed the new firmware and it appears the problem has been fixed. I have yet to test it over time though, but on the past two rides the Edge has been acting correctly when setting offset and slope.

The changes file reads they improved the user interface for ANT+ devices, so I presume that change did the trick.

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danielbahia
Posts: 48
Joined: Wed Sep 30, 2009 9:04 pm

by danielbahia

Dear guys,

Everyday before ride, I wait the Edge 800 identify the powermeter , turn the crank few times, than compare the off-set numbers, they use to be similar. On my MTB X.0 crank the SRM shows from 695 to 710.

Today after riding for 20 minutes the power dropped to 0 "zero" than increased a little, than dropped again. Typical behavior of low bat. But mine have been recently changed. I stopped the bike and tried to calibrate again, the number was 1980 this time... I did the same procedures, saved the 715 and kept my training session. The problem have not repeated anymore.

Some of you have the minimum idea about what is going on?

Thank you so much!

alexaqui
Posts: 29
Joined: Fri Dec 13, 2013 6:42 pm

by alexaqui

Seems that the problem is that you are using a Garmin. Why not pick up a refurbished PC7 for less money than your "feature packed" and buggy Garmins? My life has improved so much since I switched from a PowerTap and Garmin setup to a SRM/SRM setup. It just works. If you want to do social media activities like tracking your routes via mapmyride/Strava, you can always use your phone. At least the important stuff will be super duper reliable (e.g., power, HR, speed, cadence).

by Weenie


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