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-   -   Issues with combined speed/cadence sensors, Garmin GPS (https://www.bikeforums.net/showthread.php?t=1256706)

jgwilliams 08-11-22 10:44 AM

Issues with combined speed/cadence sensors, Garmin GPS
 
I'm wondering if anyone else has had issue with combined speed/cadence sensors on Garmin GPS units? When I bought an Edge 520 Plus I kept my Garmin GSC-10 that came with the old Edge 705, and for a long while it worked fine. Then one day it appeared that the speed sensor side failed; that wouldn't have been a problem except that rather than using the GPS for speed my 520+ decided I was doing 0 mph. I had a spare GSC-10, so I popped that on, but some time later the same seemed to happen to that. So then I bought a Topeak Duoband unit, which worked fine. I then upgraded the Garmin to a 530, and it has continued to work fine until just recently, when the same thing happened.

I find this a bit more than coincidental. I've taken the Duoband off and tested it, and I can confirm that the speed sensor itself is working as it operates a diagnostic LED for the first x number of pulses, so I have to conclude that it's something to do with the Garmin software. The Duoband has both ANT+ and BT, so I thought I'd switch the Garmin connection to BT to see if that does the trick. I do have a magnet-free cadence sensor, but the area I cycle in has a lot of tree cover, so the speed displayed can be a bit erratic if I rely purely on GPS.

Barry2 08-11-22 11:18 AM

IF the firmware is updatable on the Speed Sensors... Have you performed the updates?

Barry

sean.hwy 08-11-22 11:26 AM

I have a gravel bike with four wheel sets. Only one wheel set has the speed sensor. My garmin 1030+ switches to gps mode when I use the wheels without the sensor.

I know it's using the speed sensor because I check it before each ride. I pickup the bike and pedal in place ( bike not moving / rear wheel spinning ) and the head unit shows speed is moving.


I have had my heart rate monitor or maybe it's the head unit freeze at one heart rate say like 119 even though I know I am more like 150+ while going up hill. I think that's because of low battery though in the heart rate monitor.

Iride01 08-11-22 02:49 PM

I'm having trouble understanding the question too.

Is it just that you keep having sensors fail?


Don't know what to say. I still use my GSC-10 with my Garmin Edge 530. It was given to me by a bike shop owner/mechanic circa 2016 after hearing the story of my water bottle falling out of it's cage and knocking my previous GSC-10 off the bike and losing the battery cover. It came out of his junk bin so no telling how old it is.

I haven't had any issues. Though I'm starting to wish it would fail so I can justify getting the new style Garmin speed sensor. Cadence comes from the PM now so I'm not using that side of the GSC-10.

njkayaker 08-11-22 04:41 PM


Originally Posted by jgwilliams (Post 22606831)
I'm wondering if anyone else has had issue with combined speed/cadence sensors on Garmin GPS units?...

There are many of these sensors out there. I haven't heard of problems.


Originally Posted by jgwilliams (Post 22606831)
...and I can confirm that the speed sensor itself is working as it operates a diagnostic LED for the first x number of pulses,...

You confirm that it's working by picking the bike up and spinning the wheel and seeing the speed displayed.


Originally Posted by jgwilliams (Post 22606831)
...so I have to conclude that it's something to do with the Garmin software.

There are many of these sensors out there. If was something to do with the Garmin software generally, it seems likely that lots of people would have the issue.

Since it appears they don't, one could conclude there's something wrong with your particular unit.

You could try leaving the battery out for a while and reinserting it. and seeing if that changes anything,

Buzzkill53120 08-11-22 05:25 PM

Garmin has a page that addresses the issue you are having: https://support.garmin.com/en-US/?fa...xP313am1qAM3m9

jgwilliams 08-12-22 01:45 AM


Originally Posted by sean.hwy (Post 22606898)
I have a gravel bike with four wheel sets. Only one wheel set has the speed sensor. My garmin 1030+ switches to gps mode when I use the wheels without the sensor.

I know it's using the speed sensor because I check it before each ride. I pickup the bike and pedal in place ( bike not moving / rear wheel spinning ) and the head unit shows speed is moving.

Yes, mine will do the same if the speed sensor is missing before I start the ride. In my case I start the ride and all is fine, then after a bit the speed on the Garmin suddenly drops to zero. It's still picking up cadence so I know the sender is working. I have to disable the sensor in the Garmin settings to get it using GPS again. As I mention above, the speed sensor still appears to be working, but the Garmin isn't picking it up. After some messing around I can usually get them talking again. It's quite frustrating.

jgwilliams 08-12-22 01:57 AM


Originally Posted by njkayaker (Post 22607269)
You confirm that it's working by picking the bike up and spinning the wheel and seeing the speed displayed.

No, in this case it seems you can't. The unit is still sending cadence data and the diagnostics confirm that it's picking up the wheel magnet pulses, so clearly there's a failure of communication between the two.


There are many of these sensors out there. If was something to do with the Garmin software generally, it seems likely that lots of people would have the issue.

Since it appears they don't, one could conclude there's something wrong with your particular unit.
If it were just one unit, or even one GPS unit, I might agree. To have the same problem with two GSC-10's and a Topeak on two different Garmin units makes it look like something else is involved.


You could try leaving the battery out for a while and reinserting it. and seeing if that changes anything,
Yes, I generally get it going again.I was hoping someone here might have some insight. On the GSC-10 it was merely a bit awkward to get the battery out in situ. With the Topeak unit you have to remove it from the bike - although it's otherwise a much neater unit.

njkayaker 08-12-22 04:41 AM


Originally Posted by jgwilliams (Post 22607596)

If it were just one unit, or even one GPS unit, I might agree. To have the same problem with two GSC-10's and a Topeak on two different Garmin units makes it look like something else is involved.

Err. It’s a bit hard to follow what you did. You probably shouldn’t regret to the sensors as “units”.

Yes, it’s odd that you have the same problem with two Garmin sensors.

Small chance, but it’s possible both sensors have the same problem. One thing common with both is the magnet. Another common thing is the head unit.

The GSC-10 sends the wheel and cadence data together (I think). So, it’s not an issue with losing connection to one data stream. (The Varia RT-515 has separate streams for the radar and light).

The GSC-10s don’t use BT (so, changing that wouldn’t be expected to change anything).

Chuck M 08-12-22 04:51 AM

When is the last time you changed the battery in the sensor? You may have enough battery that the sensor sees the magnet, but not enough to transmit to the Garmin.

jgwilliams 08-12-22 05:04 AM


Originally Posted by njkayaker (Post 22607624)
Err. It’s a bit hard to follow what you did. You probably shouldn’t regret to the sensors as “units”.

Yes, it’s odd that you have the same problem with two Garmin sensors.

The GSC-10s don’t use BT (so, changing that wouldn’t be expected to change anything).

Sorry. It's a bit hard to explain and I never was very good at narrative - that's why I don't have a customer facing job.

No, GSC-10 doesn't have BT, but the Topeak Duoband does. I haven't been out since switching it to BT but the initial setup seemed to go OK.


Originally Posted by Chuck M (Post 22607626)
When is the last time you changed the battery in the sensor? You may have enough battery that the sensor sees the magnet, but not enough to transmit to the Garmin.

If that's the case then how come the Garmin always continues to pick up the cadence. I did change the battery recently, after the first time I had trouble with the Topeak unit. The two GSC-10s are in a drawer somewhere; I'd sort of assumed they were broken but I'm beginning to think now that perhaps they aren't.

rm -rf 08-12-22 05:38 AM

Both of my GSC-10 wheel sensors quit working recently. One of them at first. It was intermittent while riding. (I'd had occasional sensor problems in past years, but it "fixed itself", and a stronger magnet helped, too). This time, a new battery didn't fix it. So I installed the other one, and it failed a few months later.

The blinking status light didn't flash when the magnet passed by, so I think it was dead.

With the GSC-10, the spoke magnet position was critical. If it was moved maybe 5mm, it just didn't trigger consistently. And the gap needed to be very narrow. I adjusted while watching the status light flashing.

One sensor was probably 15 years old? The other one about 8 years.
~~~
I switched to the Garmin Speed Sensor2, wrapped around the front wheel hub. That's easier and works consistently. (I had to turn off it's bluetooth ride uploads! it started a new "ride" on my phone's Garmin Connect every time I walked the bike, turning the wheel. No!)

njkayaker 08-12-22 06:29 AM


Originally Posted by jgwilliams (Post 22607633)
Sorry. It's a bit hard to explain and I never was very good at narrative - that's why I don't have a customer facing job.

It’s not easy to do. I’m pointing it out because it’s part of why you aren’t getting useful help.


Originally Posted by jgwilliams (Post 22607633)
No, GSC-10 doesn't have BT, but the Topeak Duoband does. I haven't been out since switching it to BT but the initial setup seemed to go OK.

The way you wrote it suggested it might do something for the GSC-10 sensors.

It doesn’t seem you were having issues with the Topeak sensor. So, it doesn’t seem the BT change is relevant to anything.

jgwilliams 08-12-22 06:41 AM


Originally Posted by njkayaker (Post 22607673)
It’s not easy to do. I’m pointing it out because it’s part of why you aren’t getting useful help.


The way you wrote it suggested it might do something for the GSC-10 sensors.

It doesn’t seem you were having issues with the Topeak sensor. So, it doesn’t seem the BT change is relevant to anything.

Ok, my apologies. Yes, the Topeak sensor has done exactly the same - twice now.

njkayaker 08-12-22 06:58 AM


Originally Posted by jgwilliams (Post 22607680)
Ok, my apologies. Yes, the Topeak sensor has done exactly the same - twice now.

So, you also have a Garmin cadence sensor being used at the same time?

If you are running a cadence sensor at the same time, it's possible the Garmin is dropping the combo sensors in preference (it doesn't know what to do with two cadence streams).

jgwilliams 08-12-22 09:14 AM


Originally Posted by njkayaker (Post 22607699)
So, you also have a Garmin cadence sensor being used at the same time?

Oh dear! I wish I could go back and start again. It all made perfect sense in my head when I wrote it. :foo:

No. After the last round of trouble I did put a magnetless cadence sensor on the bike, but it's currently disabled. It's just on there so that if the Topeak one plays up again I can quickly stop and disable it and enable the cadence sensor.

njkayaker 08-12-22 09:28 AM


Originally Posted by jgwilliams (Post 22607837)
Oh dear! I wish I could go back and start again. It all made perfect sense in my head when I wrote it. :foo:

No. After the last round of trouble I did put a magnetless cadence sensor on the bike, but it's currently disabled. It's just on there so that if the Topeak one plays up again I can quickly stop and disable it and enable the cadence sensor.

You sure do have lots of sensors!

You should simplify stuff and get a magnetless wheel sensor (and not use all the others, except for the cadence one).

====================

You have 4 combo sensors (used individually) and there’s an intermittent issue with speed.

There’s also a cadence sensor that is disabled on the 520 but it’s still sending signals.

While it should work, it’s an unusual arrangement.

jgwilliams 08-12-22 09:43 AM


Originally Posted by njkayaker (Post 22607858)
You sure do have lots of sensors!

You should simplify stuff and get a magnetless wheel sensor (and not use all the others, except for the cadence one).

Yes, I probably will in due course. They're a bit expensive and I can't afford to just go out and buy them on a whim. I got the Topeak one at a bargain price and it's been quite good up to now. I have a spare cadence sensor because it was ultra cheap and turned out to be not a very good one. I managed to pick up a genuine Garmin one to replace it on Ebay quite cheaply. But the two Garmin magnet-less sensors I have are for the mountain bike, as I find the combined ones can get knocked out of place quite easily during some vigorous downhill activity. I once did a really good time (at least, it felt like it) on a local trail only to find that the wheel magnet had been knocked askew and, once again, the Garmin had registered 0 mph for most of it. :(

Iride01 08-12-22 09:58 AM


Originally Posted by jgwilliams (Post 22607874)
I once did a really good time (at least, it felt like it) on a local trail only to find that the wheel magnet had been knocked askew and, once again, the Garmin had registered 0 mph for most of it. :(

Your times shouldn't be affected by the wheel sensor issue. So you can calculate yourself what your average is for the ride. Though I'd be surprised if the errant wheel sensors messed up anything for Garmin Connect or other sites that generally run their own calculations with the position and times stamp data. But since I don't ever have those issues, I suppose I might be wrong in my thinking.

Still the time you stopped your timer is more or less the time of your ride.

njkayaker 08-12-22 10:00 AM


Originally Posted by jgwilliams (Post 22607874)
Yes, I probably will in due course. They're a bit expensive and I can't afford to just go out and buy them on a whim. I got the Topeak one at a bargain price and it's been quite good up to now. I have a spare cadence sensor because it was ultra cheap and turned out to be not a very good one. I managed to pick up a genuine Garmin one to replace it on Ebay quite cheaply. But the two Garmin magnet-less sensors I have are for the mountain bike, as I find the combined ones can get knocked out of place quite easily during some vigorous downhill activity. I once did a really good time (at least, it felt like it) on a local trail only to find that the wheel magnet had been knocked askew and, once again, the Garmin had registered 0 mph for most of it. :(

When you get the bill for the diagnosing effort, you are going to wish you just bought a sensor!

Nothing is going to be perfect.

The 520+ doesn't (as far as can tell) have a general problem with this. The GSC-10 doesn't (it's been a round for a very long time). Topeak is a competent company (so their sensors should be fine).

The issue with magnets is one reason I mentioned the other type. It's possible that your issue is the sensor(s) moving around a bit. Maybe, the magnet is weak.

===================

This thread would be more appropriate for the Electronics subforum.

jgwilliams 08-12-22 10:07 AM


Originally Posted by Iride01 (Post 22607896)
Your times shouldn't be affected by the wheel sensor issue. So you can calculate yourself what your average is for the ride. Though I'd be surprised if the errant wheel sensors messed up anything for Garmin Connect or other sites that generally run their own calculations with the position and times stamp data. But since I don't ever have those issues, I suppose I might be wrong in my thinking.

Still the time you stopped your timer is more or less the time of your ride.

Take a look at this Ride with GPS link. If you look at the distance trace you can see I apparently climbed a vertical hill. The time trace smooths it out but you can see the speed at the top part of the hill is registered as 0mph. It messes up the record and would mean, for example, that I couldn't have got a PR on that trail I mentioned above.

Iride01 08-12-22 12:46 PM


Originally Posted by jgwilliams (Post 22607910)
Take a look at this Ride with GPS link. If you look at the distance trace you can see I apparently climbed a vertical hill. The time trace smooths it out but you can see the speed at the top part of the hill is registered as 0mph. It messes up the record and would mean, for example, that I couldn't have got a PR on that trail I mentioned above.

PR's, at least for me are time based. So I'm not sure why if you make a segment out of that stretch why you wouldn't get a PR if you bested your previous times. Have you made a segment out of that section? I see a Hurst Lane Short segment, but I don't think that is the area on the profile you are talking about.

I might be wrong, but I think if you make a segment of that area, it will pull in all your past rides of that area. Though it might take a day or so to pick them up. And you can see if you do or don't get a PR for that ride or if in fact there is some incorrect way RWGPS is tallying times. I've always imagined that for such they use the GPS timestamp in the file. However it is interesting that there is a jump in the elevation right at the time the cadence craps out. I'll have to ponder that for a while. Maybe some others that mess with this stuff more seriously might know a possible reason.

https://cimg5.ibsrv.net/gimg/bikefor...2cd5657dfe.png
distance
https://cimg6.ibsrv.net/gimg/bikefor...932c3b468d.png
time


As for the profile looking wonky, they always do and I don't put much into them when I'm looking at what in this case is almost 121,440 feet (37.5 km) of x axis scaled against roughly 500 feet (150 metres) of elevation on the y axis. I always select out just the portion I'm curious about and look at it in both distance and then against time.

masonv45 08-12-22 12:51 PM

If I can make a suggestion, just use the GPS on the Garmin Edge you are using for speed - and add a Magene sensor to your pedal crank (set to cadence).

I've done this on my Edge 520 with no issues for at least a year now.

jgwilliams 08-15-22 02:40 AM


Originally Posted by masonv45 (Post 22608174)
If I can make a suggestion, just use the GPS on the Garmin Edge you are using for speed - and add a Magene sensor to your pedal crank (set to cadence).

I've done this on my Edge 520 with no issues for at least a year now.

Yes, I can do that. As I mentioned in the original post, though, we have quite a lot of tree cover here and I find the speed a bit erratic when using just GPS. This is more noticeable when mountain biking, but at this time of year, with lots of leaf cover, it affects the speed reading on the road bike too. I know it doesn't matter greatly but I'd rather have an accurate speed if I'm recording everything.

roadie276 08-15-22 08:22 AM


Originally Posted by jgwilliams (Post 22610490)
Yes, I can do that. As I mentioned in the original post, though, we have quite a lot of tree cover here and I find the speed a bit erratic when using just GPS. This is more noticeable when mountain biking, but at this time of year, with lots of leaf cover, it affects the speed reading on the road bike too. I know it doesn't matter greatly but I'd rather have an accurate speed if I'm recording everything.

FWIW I also prefer the speed sensor for accuracy and speed of updating...I find that GPS can have a lag with it that's not there with a cadence-based speed sensor, and it can be annoying. I use a Duotrap S sensor (which is only an option if your frame supports it, I think).


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