I finally decided to buy a decent HRM, so I picked up a Polar S120.
I found it to be really user-unfriendly & the buttons are a pain. However, it worked. It gave me what I wanted to see on the run.
Then I got on the bike. As soon as I started moving my HR jumped to 200 and went as high as 220 while cycling. It came back to normal when I stopped. Since the peak occurred even when coasting (cadence of 0 rpm) I deduced that I am getting some interference with my speed sensing magnet on my Cat Eye comp. This was not a problem with my previous, el cheapo monitor. So now I am not going to bother with other Polars and give Timex a shot with their HRM.
I get interference from high-voltage power lines (the ones that crackle) once in while with my S625X. While coasting to a stop sign on Route 1 in Princeton my cadence was 200, HR was 220, and I was going 65 mph. I looked up quickly and saw some larger power cables.
I get some high readings from wind. Going downhill in the first 20 minutes of a ride gives me a reading in the 200’s. At first I thought I was experiencing some tachacardia…scared the @#$% out of me.
Your problem really sounds like it’s due to interference with the cateye (I’m assuming you have a wireless computer). Search these forums and elsewhere for further discussion of the problem you’re describing. Is your HR monitor coded? If so, I’ve read that if you engage the HR monitor before riding the bike it may lock into it’s own frequency (or whatever codes it) and prevent interference from the bike computer.
I had the same problem a few weeks ago. I replaced the battery and the problem persisted. You may want to check the connectors where the strap clicks into the battery holder. I noticed they had collected some fuzz and dirt. My problem cleared up once I took a Q-Tip with rubbing alcohol to them.
I had a similar problem that really appeared when I rode in the aero-bars. The strap needed to be tightened so when in the bars the contacts stayed on my skin. I did not have a problem when running.
I constantly had problems with my timex hrm. besides eating batteries, the hrm would read 1/2 my hr for a while then go back to the correct number. I finally gave up on it when some one gave me a polar 625x. the only time I have a bad reading from the polar is when the hr strap is dry. it would read high for a few minutes till I start sweating then settle down so now, I wet the strap before putting it on.
I read on the Polar website that some synthetic material in jerseys causes interference (in addition to a host of other things) they recommended wetting a flapping jersey to see if it resolves the problem.
I have the exact same Polar HRM and the exact same problem. It was only this year I started using the HRM on bike rides instead of runs and had never had the problem before while running. I have a wired Specialized computer with magnet on the front wheel. I ride in some areas with electrical wires and some areas without and the problem doesn’t seem to arise from the wires because it randomly occurs. I’m going to try tightening the strap to see if that helps. Anyone else with any thoughts would be greatly appreciated as this is quite annoying.
I don’t know if this will solve your problem, but you can also turn the strap around so the sensors are on your back. That gets gravity working for you. It should help if contact is the problem, but won’t help at all if there is interference.
As a few have allready pointed out it sounds like the HR strap contact points are moving when you are riding.
I’ve seen the same problem both with polar and timex, the cause was either my strap was not tight enough or my skin was dry and signals where not being picked up initially.
With dry skin on a dry sensor I commonly see double HR readings for the first couple of mins before I start to sweat.
Well I will give this a shot on my next ride in a few days but I noticed the problem on the whole 1 hr 40 min ride, and I definitely sweat a lot. I will tighten it and keep it wet.
The weird thing is that this all goes back to my $19.99 cheap-o HRM never had a problem with all of this. Grr…
Tried tightening the strap and starting it only after riding for a bit. It worked! For the first 5 minutes that is.
It seemed better in that the high readings only came intermittently and I am trying to isolate if it occurs on real bumpy stretches but it would always happen there.
My next experiment (2 more rides until I can return it to REI) is with my cheapo monitor’s (Lifesource) chest strap.
I think the S120 does not run a coded strap (my guess is your strap says t-31 or something like that on it.) Without being coded the watch will be more likely to pick up random signals. Unfortunately I think you need to upgrade to a higher level model to get the coded system (strap will say T-61) that will be less likely to pick up interference. Even in Socorro there are enough power lines and cell towers that you can pick up some random signals. Even though your computer is wireless, it can still create a slight signal because of the current that runs through the wire.
I don’t think this will help. Even if you use a coded strap, which you can do, the S120 is not coded so you get no benefit. A while back I used a WearLink chest strap with the S120. It works fine (well it works no worse than with the uncoded strap that ships with the S120) but the S120 will still pick up noise from other transmitters.
Yeah, I get all sorts of weird readings from my HRM especially when descnding so I assumed it would be my jersey falpping around or something like that, so I tried squirting my chest from a water bottle and it comes right.
It seems to be pretty ok after an hour or so, I guess when I’m constantly sweaty…