SRM/Garmin Issues

Triathlon Forum
1

I have a brand new (bought in August) SRM DA9000 and a Garmin Edge 500. I used to have a quarq and only really had power drops when I was on the trainer. I attributed those drops mainly due to signal interfence (wireless network and utilizing my Sono’s system from my phone while on the trainer). I never remember getting any power drops when riding outside with my quarq. Since I’ve gotten my SRM, I get probably 3-5 power drops on a 2-3 hour ride outside. Cadence completely drops to zero and then power drops (when the power drops, cadence is always zero). When I’m on the trainer, the same thing happens but also when I’m setting my bike up, I will get the power meter calibrated and then go off and get my water bottles filled, change into bike clothes, etc and then come back 10-15 min later and finally hop on the bike. When I do this and start pedaling, cadence and power are zero. I have to go back through the edge 500 and recalibrate again for cadence and power to start showing up.

Given that cadence is always zero when power is zero, this leads to believe the issue is not the SRM pm itself but either the edge 500 picking up the signal through ant+ or possibly my magnet location on the bike (although I don’t think its the magnet because I would think cadence would always be zero if the magnet was the issue). FWIW, I have a 9 series trek SC (newest version) and have the cadence magnet mounted inside the speed fin via super glue.

Anyone else have similar issues? What did you do to resolve? I’ve been doing some reading and some people seem to think a power control unit doesn’t have the communication issues that garmin has with srm pm’s. I’m ok with going that route but I would wait until the PC8 comes out.

2

It’s generally a good recommendation to use a PowerControl with SRM rather than Garmin. The Edge 500 sometimes reports 0 power whenever it has problems getting a GPS signal (not sure if this is the cause of your particular issue or not). In addition, it is not possible to turn off the SRM auto zero function using an Edge 500. Here is some more information on the SRM / Edge 500 auto-zero flaw - http://alex-cycle.blogspot.com/2013/03/three-two-one-zero-offset.html. There is also a lengthy discussion on the Google Wattage forums about this.

FWIW I’ve used my Edge 500 with both a Quarq S975 and a PowerTap G3 and have also experienced the same issues - power/cadence both reading zero (usually at the beginning of a ride outdoors).

Who knows when PC8 will finally be released. SRM has pushed back the release date about 2-3x so far, and they’re going to miss their latest promised release date of Dec. SRM says they will allow PC7 owners to upgrade to PC8 for a discounted price whenever it comes out. I didn’t want to wait an unknown amount of time for the PC8, and given that it was an unknown variable (it will include GPS and some other new features that may cause issues) - I went ahead and got a PC7.

3

A couple of other ideas. Are the dropouts random? I experience power and cadence drops on my SRMs with either the PC (VI) or Garmin (800) on my rides when passing HT power lines. This is a very consistent phenomenon occurring at 3 specific locations and not all powerlines. Otherwise the different combinations of PMs and head units are very reliable. Also, even though your SRM is relatively new, this could be the beginning of battery failure (FWIW I had one come back from SRM USA with a bum battery which failed soon after their service).

4

It’s generally a good recommendation to use a PowerControl with SRM rather than Garmin. The Edge 500 sometimes reports 0 power whenever it has problems getting a GPS signal (not sure if this is the cause of your particular issue or not).

I have never experienced that, ever–and I regularly ride through a tunnel where I lose GPS signal (and I’m not using a speed sensor). More likely, his issue is that the cadence magnet isn’t placed correctly (either too high/too low, or too close/far).

In addition, it is not possible to turn off the SRM auto zero function using an Edge 500. Here is some more information on the SRM / Edge 500 auto-zero flaw - http://alex-cycle.blogspot.com/2013/03/three-two-one-zero-offset.html. There is also a lengthy discussion on the Google Wattage forums about this.

Most of the people “discussing it” are just basing opinions off that one blog post, and have very limited understanding of how the AZO actually works. In my experience, while it has the potential to throw an error it also has the potential to be more accurate if you’re riding in variable temperatures—and the problems with it are greatly overstated. The problem seems to be that most people don’t seem to understand how to actually check the stored offset (Alex included–pulling over to check the stored ZO does not actually tell you the stored offset while you’ve been riding-you have to check it while you’re pedaling). If you’re riding in stable temps, disabling the AZO makes sense, but if you’re riding on a day or terrain with a 20-30 degree temperature change–or you’re the sort to forget to manually zero when you leave a warm house and go out into cold weather, you’re better off leaving the AZO “on”, IMO.

5

I don’t ride outside enough to know off the top of my head if they are random. I would need to look back at the data but I’m pretty sure they are random.

6

Do you have an edge 500 paired with an srm?

My original thought was it was the magnet but after reading a few things online, they had me thinking differently. I’m still a little confused if it really is the magnet as I would expect a lot more drops or no power/cadence readings at all. I may just get the kedge/srm magnet/chain catcher and see how that works. Just to rule out the issue at least. I’d rather buy a 60 dollar part than spend a couple hundred on a new PC and it still doesn’t fix the issue.

7

Do you have an edge 500 paired with an srm?

My original thought was it was the magnet but after reading a few things online, they had me thinking differently. I’m still a little confused if it really is the magnet as I would expect a lot more drops or no power/cadence readings at all. I may just get the kedge/srm magnet/chain catcher and see how that works. Just to rule out the issue at least. I’d rather buy a 60 dollar part than spend a couple hundred on a new PC and it still doesn’t fix the issue.

Yes, on a couple of different bikes. It’s pretty sensitive to magnet placement–and I’ve had the same issue of either random dropouts or a random, temporary doubling of power (like it’s doubling cadence). The latter seems to be when placement is too close. So, I wouldn’t assume it’s not the magnet just because it works some/most of the time. On old bikes with conventional BB’s, set-up was pretty simple with the BB-mounted magnet, but with newer frames it seems there’s some experimentation required to get it right. No guarantees it’s the magnet, but I’d start there.

8

In addition, it is not possible to turn off the SRM auto zero function using an Edge 500. Here is some more information on the SRM / Edge 500 auto-zero flaw - http://alex-cycle.blogspot.com/2013/03/three-two-one-zero-offset.html. There is also a lengthy discussion on the Google Wattage forums about this.

Most of the people “discussing it” are just basing opinions off that one blog post, and have very limited understanding of how the AZO actually works. In my experience, while it has the potential to throw an error it also has the potential to be more accurate if you’re riding in variable temperatures—and the problems with it are greatly overstated. The problem seems to be that most people don’t seem to understand how to actually check the stored offset (Alex included–pulling over to check the stored ZO does not actually tell you the stored offset while you’ve been riding-you have to check it while you’re pedaling). If you’re riding in stable temps, disabling the AZO makes sense, but if you’re riding on a day or terrain with a 20-30 degree temperature change–or you’re the sort to forget to manually zero when you leave a warm house and go out into cold weather, you’re better off leaving the AZO “on”, IMO.

Not sure that’s the right blog post, I think this is the relevant one:
http://alex-cycle.blogspot.com.au/2013/03/more-zo-zen_7.html

What do you mean that you can’t check the stored ZO when stopped? Of course you can. The SRM shows you two values when you go into torque (zero offset) mode on the Powercontrol, the most recently stored ZO and the current “live” torque reading.

Why do you assume I haven’t also observed AZO behaviour while moving just because I didn’t post about it? I didn’t post such data since between the choice of taking a picture of it while moving and killing myself, I chose to be safe and stop to take a photo instead. In fact it was because I had checked while moving that prompted me to stop and record it via photo.

While moving I have seen ZO swings of hundreds of Hz while AZ is enabled (yes, hundreds of Hz), and associated ridiculous power numbers. It’s not normally as bad as that, but because there is no log of zero offset changes, who can actually know what values it stores, how frequently it updates and what level of unknown error is introduced long the way? It’s not like the AZO screen remains on forever when you go in to ZO mode.

The fact that I saw variation in the most recently set auto zero when stopped a few times, when in fact actual ZO had barely moved is sufficient to tell me that it is flawed for me. The sort of swings I would observe with AZO enabled were greater than any actual temperature induced ZO change may have been (which on my units is not all that much in any case).

As always, YMMV

9

In addition, it is not possible to turn off the SRM auto zero function using an Edge 500. Here is some more information on the SRM / Edge 500 auto-zero flaw - http://alex-cycle.blogspot.com/2013/03/three-two-one-zero-offset.html. There is also a lengthy discussion on the Google Wattage forums about this.

Most of the people “discussing it” are just basing opinions off that one blog post, and have very limited understanding of how the AZO actually works. In my experience, while it has the potential to throw an error it also has the potential to be more accurate if you’re riding in variable temperatures—and the problems with it are greatly overstated. The problem seems to be that most people don’t seem to understand how to actually check the stored offset (Alex included–pulling over to check the stored ZO does not actually tell you the stored offset while you’ve been riding-you have to check it while you’re pedaling). If you’re riding in stable temps, disabling the AZO makes sense, but if you’re riding on a day or terrain with a 20-30 degree temperature change–or you’re the sort to forget to manually zero when you leave a warm house and go out into cold weather, you’re better off leaving the AZO “on”, IMO.

Not sure that’s the right blog post, I think this is the relevant one:
http://alex-cycle.blogspot.com.au/2013/03/more-zo-zen_7.html

What do you mean that you can’t check the stored ZO when stopped? Of course you can. The SRM shows you two values when you go into torque (zero offset) mode on the Powercontrol, the most recently stored ZO and the current “live” torque reading.

Why do you assume I haven’t also observed AZO behaviour while moving just because I didn’t post about it? I didn’t post such data since between the choice of taking a picture of it while moving and killing myself, I chose to be safe and stop to take a photo instead. In fact it was because I had checked while moving that prompted me to stop and record it via photo.

While moving I have seen ZO swings of hundreds of Hz while AZ is enabled (yes, hundreds of Hz), and associated ridiculous power numbers. It’s not normally as bad as that, but because there is no log of zero offset changes, who can actually know what values it stores, how frequently it updates and what level of unknown error is introduced long the way? It’s not like the AZO screen remains on forever when you go in to ZO mode.

The fact that I saw variation in the most recently set auto zero when stopped a few times, when in fact actual ZO had barely moved is sufficient to tell me that it is flawed for me. The sort of swings I would observe with AZO enabled were greater than any actual temperature induced ZO change may have been (which on my units is not all that much in any case).

As always, YMMV

Please re-read what I wrote. I didn’t say you couldn’t check the ZO when stopped–I said it’s not representative of the ZO when you’re actually pedaling–because it’s not. As soon as you stop, if a certain set of conditions are met the AZO will re-set it. I’m not asking you to make my word for it–check for yourself–but check it WHILE you’re pedaling, then check it when you stop. I have (an embarrassing number of times). Checking the ZO after stopping almost never reflects the ZO when riding, since it resets during the act of stopping.

I don’t know what you have or haven’t observed (I can only go by what you posted)–but I can tell you what I’ve observed: checking the ZO into the hundreds of times (while riding), I’ve seen 4 or 5 samples that varied more than 8 hz, and probably 10 samples that varied more than 5 hz. I also have about two dozen power files while using a 510 and 500 concurrently, with autozero set to “off” on the 510. On intervals from :30 to 15:00, 4W (on a 30 second interval) is the biggest differential I’ve seen.

Meanwhile, I’ve had the actual ZO drift by 30hz in a race (not common conditions, but it happens). Mind you, I’m not telling anyone to take my word for it. What I’m saying is that folks should experiment with it for themselves, and not be so dismissive of it because they’ve read on the internet that it sucks (no offense to you Alex, but my own experience with the AZO is that it works pretty well). In absence of the ability to do it manually (such as during a race), I can see it leading to more accurate data in certain circumstances.

10

i’d be curious to know the percent of SRM owners that have Garmin products vs the PC products…any educated estimates?

11

Please re-read what I wrote. I didn’t say you couldn’t check the ZO when stopped–I said it’s not representative of the ZO when you’re actually pedaling–because it’s not. As soon as you stop, if a certain set of conditions are met the AZO will re-set it. I’m not asking you to make my word for it–check for yourself–but check it WHILE you’re pedaling, then check it when you stop. I have (an embarrassing number of times). Checking the ZO after stopping almost never reflects the ZO when riding, since it resets during the act of stopping.

I don’t know what you have or haven’t observed (I can only go by what you posted)–but I can tell you what I’ve observed: checking the ZO into the hundreds of times (while riding), I’ve seen 4 or 5 samples that varied more than 8 hz, and probably 10 samples that varied more than 5 hz. I also have about two dozen power files while using a 510 and 500 concurrently, with autozero set to “off” on the 510. On intervals from :30 to 15:00, 4W (on a 30 second interval) is the biggest differential I’ve seen.

Meanwhile, I’ve had the actual ZO drift by 30hz in a race (not common conditions, but it happens). Mind you, I’m not telling anyone to take my word for it. What I’m saying is that folks should experiment with it for themselves, and not be so dismissive of it because they’ve read on the internet that it sucks (no offense to you Alex, but my own experience with the AZO is that it works pretty well). In absence of the ability to do it manually (such as during a race), I can see it leading to more accurate data in certain circumstances.

OK, I’ve misinterpreted what you said about being able to check while stopped. Thanks for correcting me.

But just to be clear, I check the ZO while pedalling, noticed it had moved somewhat from the original ZO, stopped to record it with a photo (it did not change during the act of stopping) and compared it with an actual ZO which showed that the ZO value set by the AZO at some time before was wrong.

You suggest that the act of stopping can invoke an AZO and that it might change the ZO to a value that’s different to what it used when you were riding (I agree it can, although it may not).

So if the act of stopping causes the AZO to improperly set a new ZO as you suggest it might, and then you start off pedalling again, well you’ll be pedalling with an incorrect (or at least a different) ZO until it has the opportunity to “correct” itself at some stage. You can’t have it both ways. If it doesn’t work well when you come to a stop, then it’s not a particularly useful feature IMO.

Like I said, YMMV.

My main beef with power meters that report a zero offset / torque zero is that there is no log of changes telling us when the change occurred and the value. ZO/TZ should be a channel in the data file.

12

I had a similar issue when I first got my vector, paired with my 910xt.

I posted links to the training files on the Garmin support forums and the Tech analyzed those files and told me the vector signal strength was low causing the drop outs. Moving the 910 from my wrist to a stem mount (on a TT bike) fixed the problem. Like others have said, too, the only time mine would drop was when certain types of cars would drive by. … never did determine why not assume it was interference combined with low signal

Not sure if your problem is similar, but thought my experience might help you

Have you tried posting the question directly to SRM / Garmin yet?

13

I have an e-mail out to SRM. Waiting for a reply on them.

I went ahead and ordered the K-Edge/SRM magnet chain catcher. Will be here today. I’ll get that installed for my trainer ride tomorrow and report back tomorrow. Hopefully I can get the superglued magnet off.

14

Talked to SRM and they wanted me to send the unit back for them to look at it. Not wanting to lose my pm for a week or 2, I went ahead and installed the K-edge/srm magnet/chain catcher and took off my old magnet. 2 rides on the trainer and 1 ride outside so far with zero drops once I installed the new magnet. Going to keep monitoring my rides for the next week before I call it “fixed”.

15

I went ahead and installed the K-edge/srm magnet/chain catcher and took off my old magnet. 2 rides on the trainer and 1 ride outside so far with zero drops once I installed the new magnet. Going to keep monitoring my rides for the next week before I call it “fixed”.
I also have a DA 9000 SRM paired to a Garmin Edge 500 and while I have not had any issues with power drops, it might be due to the fact that I fixed a round 15x1 mm rare earth neodymium
magnet to the frame (Scott BB86) just behind the bottom bracket such that the magnet is within ~2mm of the face of the torque ring on the backside of the SRM.

16

What’s the verdict on the K-Edge mount? I’m having the exact same issue with my DA 9000 SRM (1 year old and nowhere near 3000 hours) & Edge 1000. My magnet is currently mounted to the inside of the speed fin on the drive side. I didn’t have any issues at all last season and these symptoms just came up this week. Hoping to fix the issue with the Kedge mount.

Thanks

17

I’ve had the k-edge installed for a little a month and have had zero drops. I’m calling it fixed for now.

That’s weird that it worked for a while and then started giving you issues out of the blue. Can’t hurt to try the k-edge first as srm will probably want you to send the unit back and you’lol be out of a pm for a week or so (unless you have another one).

18

Thanks. Ordered one today.

I spoke with SRM and they said it could be the magnet **or **the PM. Hoping the K-E solves the issue.

19

Still having issues with my Edge 1000 pairing to DA 9000 SRM. Spoke with SRM on the phone and they think it’s an issue with the latest firmware from Garmin. Paired the pm to an old PC7 and power reads perfectly. Looking forward to the PC8 release…

20

Interestng. Is this even with the k-edge magnet? I have been considering upgrading to the 1000 as I could use text/call alerts but if it’s going to cause me power drops, I’m probably going to go the pc8 route. Some say srm’s need to be paired to pc’s as the communication between an srm and garmin are intermittent. I know there are people out there with no issues with their garmin but others have only had success with a pc. Who knows…

I did have an issue on Sunday. 12 min into my ride(outside), Power dropped to zero but cadence kept reading. Had to stop and recalibrate to get power back. No other issues during the 2 hr ride. Then on Tuesday during my trainer ride, I had all kinds of power and cadence drops. I recently changed my wireless router channel from auto to manual so I’m hoping these drops on the trainer were just interference. I changed the channel back to auto after that ride as I didn’t have those drops before. I’m currently 27 minutes into a 90 min recovery on my trained. So far, no drops. I’m shrugging my shoulders at this point. I really don’t think there is an issue with my srm so I’m refraining from sending it back until I get more data that tells me otherwise. I’m about 95% on pulling the trigger on a pc8 whenever it does come out. Last they said it would be February so I hope it hasn’t changed. I have a 5 hour ride outside Sunday so we’ll see how things go.