I'm having a problem with the Garmin HRM sensor I use with my Edge 520. On yesterday's ride, for example, it was working when I started, and then stopped after about 5 miles or so. The HR space on the screen was either blank, or had some unlikely number - like 72 bpm while out of the saddle climbing a 1/4 mile 6% gradient. This continued for the next 30 miles, and then it started working again, and continued to work for the remaining 25 miles of my ride. I had JUST replaced the battery the night before, since it had been doing this for some time - the dropouts during a long ride. This is the second sensor this happened to. I got this one a couple years ago when the previous one got similarly flaky. I could understand failing completely, or giving out mid-ride and not working the rest of the ride, but working for 5-10 miles, then NOT working for 20-30 miles and starting again and working for the remainder? That makes no sense to me.

I thought it might be location-related, like maybe I'm riding through an area with a lot of radio frequency interference, but a big chunk of my ride is going the opposite direction on roads I was on earlier, so not working in one direction but working in the other also doesn't make sense.

Anyone have similar experiences with Garmin HRM sensors? Any idea what causes it? Do other vendors HRM straps do the same thing? I can buy a new one, of course, but it will eventually do the same thing, I imagine.

Might be a bad battery. Could be corrosion from sweat on the contacts between the pod and the strap. However when my Garmin soft straps start doing this at about 5 years of age, I usually find nothing works but a new strap. Garmin sells the strap without the pod for quite a few bucks less. However when I got the strap, I found out it was actually the pod. Luckily I still had the pod from my first strap and it seems to be working fine with the new strap.

The plastic was peeling off the previous strap, so I put it in the trash and never checked to see if it had issues too.

I've seen some on the Garmin forums say that they washed their strap in the washing machine with a load of clothes and it magically started working again. And I believe Garmin actually recommends machine washing every so often. Without the pod of course. I've never machine washed mine. I just rinse it well after every use.

I'm reasonably sure it's not the battery because I've had the issue before and after changing batteries, but the strap thing is a possibility. I'll give mine a wash next time I'm washing my bike stuff and see if it does anything.

My Garmin did the same thing. I replaced it with a Wahoo HRM and strap. Zero issues since.

I've had similar issues with both Garmin and Wahoo straps. This time of year, I start with electrode gel (or spit) under the strap. If that doesn't work, change the batteries. One time I got another six months or so by soaking the head and strap contacts in white vinegar -- washed all the crap off the electrodes. If it's still wonky, it's probably time for a new strap.

I was looking at my current strap this morning, and I noticed that the two contact pads that touch the skin seemed to be pulling away from the strap itself. I have another strap that seems to be in better condition. I'll give that a try, since the sensor itself has a new battery.

BTW, I was hoping someone would say it's not the strap it's the head unit, so I could justify getting a new one. You know, like how when you have a problem with shifting and somebody says "You need a new bike!"

How about the next best thing: if the different strap doesn't do the trick, get a new HRM strap. And GPS to read it. And a new bike to put the GPS on.

But you got to be careful; your partner might say "and a new body to put the strap on!"

Exactly what happened to mine about a month ago. I ordered a new strap and the sending unit didn't work in that either (I returned the strap). I decided to buy a Polar H9 and after I got it I put the Garmin unit onto the Polar strap and it didn't work either. Basically the sending unit took a dump. So far no problems at all the the Polar and it does everything the Garmin HRM did/does.

I had a love/hate relationship with the Garmin HRM that came with my Edge 830. It was punk out at the most inopportune times, and made we really try to tune into my RPE. I tried various things to get it to work; sometimes I thought I had it all figured out, but then it'd start misbehaving again.

• Re-wetting the contacts during a ride (really fun in the winter when you have a bunch of layers on)
• Washing the strap
• Changing the battery
• Changing the type of bra I used (probably not applicable to the majority of readers here)
• Swearing at it

While changing the battery a few months ago, I noticed that the transmitter's housing was separating. I contacted Garmin support, and they were kind enough to send me a new HRM (strap + transmitter) free of charge. While waiting for the replacement, I found a couple of other solutions:

• Using a rubber band on the transmitter to clamp the housing together
• Getting a $25 moofit HR8 HRM from Amazon -- it's been flawless!

Hopefully your solution will be as simple as washing the strap. If not, try contacting Garmin support, or just get a cheap $25 HRM on amazon!

Yep, I battled that issue for a few years before I switched to a Wahoo optical arm HRM. I was able to resolve it by shaving my chest hair where the pads made contact with my skin, wetting the pads and washing the strap routinely.

I really liked my Wahoo, for maybe 4 years? I forget when I got it. Then it started flaking out and then quit working. The strap was getting a bit stretched out, too.

I got a Polar H9, and like it a lot.

For a year now, it's worked very reliably with my Garmin 1030, and with Zwift.
Huh---I just fired up the phone Polar Beat app, remembered I never found a good use for it, and closed it. Even closed, it's got the bluetooth connection locked up, so the Zwift PC app can't see the Polar. Grrr. turning off bluetooth briefly on the phone fixed the Zwift connection.

Pluses:
The strap seems very well designed, and the electrode pads are smooth and well integrated into the strap.
The buckle is small and very flat -- but see the minuses below.
The strap instantly starts transmitting as soon as I put it on. I would always wet the Wahoo sensors with tap water when I put it on.

Minuses:
It's supposed to use the slightly thinner CR2025 instead of the usual CR2032. (some reports of CR2032 working, I think, but I got a 6 pack of 2025s to use on this.)
The strap adjuster is almost all the way out, and my chest is somewhat narrow. I wonder how this would fit on a larger or heavier person.
The buckle is on my left side, which works ok. But it's release is a bit fiddly to open.
I did like the tiny LED status lights on the Wahoo, just to see that it was working.

My Garmin strap recently had symptoms similar to yours. I replaced the battery and it worked fine for a couple of rides, then it started acting up again. I found out that the sensor never shut off, even when unplugged from the strap. I noticed it when I was checking the configuration on my Edge and it detected my HR sensor even though the sensor was unplugged. Basically, it was going through batteries every couple of days because it never shut off. I pried the cover off and that saved the battery but was a pain to deal with. I ended up buying a new strap.

Garmin HRM not working for me at all. I had one that didn't do too bad but it was spotty, cutting in and out all the time. I was getting frustrated as hell with it so I bought a new one, which has turned out to be actually worse. I get an hour of so and then that is about it. Spend a lot of my rides messing with strap tension and position, getting it wet to increase skin contact, removing the battery and using a piece of wire to drain the charge, replacing the battery. It just doesn't work correctly and is an endless source of annoyance. Climbing a steep bridge the other day I should be seeing 122 bpm.but I am seeing 45, typical of what is happening. Fed up I removed it from under my shirt (while pedaling ) and jammed it into my jersey pocket and it was sending 89 bpm.

I am done with Garmin as a sensor and hoping to get something off Amazon that can do the job. Any suggestions or reviews would be most welcome. BTW data going to my Edge 530, which is doing a great job with all the rest, power meter, battery sensors, shifter positions , enabled tailight, etc.

The polar H9 sounds good, any back up to that Rm's experience?

Update - getting rid of the strap that was falling apart helped, but I'm still getting dropouts that seem random. For example, Friday before last I was on Zwift, riding one of the Climb Portals. I was grinding up the climb, with my HR slowly climbing, when suddenly it dropped from 158 to 53 - which was clearly nonsense. It stayed at 53 for the next 7 minutes, while I crested the climb. Then it came back, and worked fine for the remaining 25 minutes of the ride. As far as I can tell, NOTHING CHANGED! It just stopped working for 7 minutes and started again.

Apart from that, it seems to be working okay.

Do you have a really hairy chest? Maybe trim the hair down some. Or go for that Steve Carell look he had in "The 40 Year Old Virgin". <grin>

Have you checked your data to see whether data is being logged? It could be more of a display problem on the Edge 520 than a HRM or communication problem. On my Edge 530, I occasionally have periods where some data field seems frozen, but when I look at the data later, it was logged with no issue.

I have the Garmin HRM dual and have had identical problems. Sounds like it is still the strap. Getting a new strap from Garmin doesnt always solve the problem. I had Garmin ship me 5 before I finally got one that worked more than 3 months. I recently replaced that one after 2 years with this one https://www.heartratemonitorsusa.com...28382247223401 which has the benefit of working with Polar HRMs as well. When the sending unit dies, I will replace with a Polar.