Garmin 500 Speed Sensor Problem
 

Just picked up the 500 last week and after the shop put it on and I got it home (i had dad pick it up since he was working closer to the shop than me) and the magnet rubbed on the chainstays. I tried adjusting the magnet up and down the spokes and putting the magnet on the opposite spoke, but either it doesn't pick up the signal or it rubs the stays. Any ideas until I can get it back into the shop to have them look at it?

Are you running a tri/TT bike? Try placing the magnet closer to the hub where the stays are wider.

Nope...09 Tarmac Expert. Keep in mind that the cadence also needs to be picked up by the sensor

You can also adjust the speed sensor by loosening the screw on it. And you probably don't need the sensor unless you're on the trainer.

And if that fails, replace the battery with a fresh one.

I have a 2011 Tarmac Expert, no issues as at all... and in my experience, you DO need the speed sensor to use the cadence sensor. My speed sensor went out and it would not revert to GPS for speed, it would actually assume I wasn't moving even though I had cadence. I had to turn the speed/cadence sensor off in settings until Garmin sent me a new cadence unit. Now all is well. But I could not get everything to work without the speed sensor...

PIctures of the current setup? I'm having trouble visualizing how the magnet hits the stays

Hit the reset button on the transmitter and see if it starts working again.

I'm not really visualizing what OP is describing. A picture would be helpful. Both of my sensors have been remarkably easy to install (and adjust). Lines to tell you exactly where to align everything.

Unless you've got the crank magnet in a weird place, everything ought to work without having to hold your tongue a certain way. Where is that crank magnet? Toward the end of the crank, or toward the middle?

??? You mean the "wheel magnet rubs the sensor arm" don't you? As someone said, there is a screw that allows movement of the sensor arm to take care of that.

I'll take it as written and say your wheel magnet is hitting the chainstay and not the sensor arm, right? If the magnet on the opposite spoke is too far away (doesn't pick up signal), have you tried twisting the magnet around the spoke so it is "backwards"? In other words, the shiny part of the magnet is facing the drivetrain, opposite of photo.

http://lh5.ggpht.com/_Wo8yCZ1eTVw/Ta...268%5B5%5D.jpg

I think the problem is still in the swing arm on the sensor. First, get the magnet to a place on the spokes where it doesn't rub on the chainstay. Then adjust the arm on the pickup so it's close enough to the magnet to pickup.

If you don't adjust the arm, it can be difficult to get both sensors to pickup and nothing scraping. That's why you can loosen that little screw and adjust the arm.

NOPE...magnet on chainstays.

Finally found some time to take it into the shop today since I got out of work on time and didn't it traffic, and they had to replace the stock magnet with a low profile one. I would have wasted lots of valuable time trying to fix something even they couldn't

Strangest problem I've read about in a while on here. I can't imagine any way a low profile magnet would be needed. I bet there are hundreds or even thousands of tarmacs out there with the GC-10 sensor working as-is.

I'd be great if you could post a picture of how they have that thing setup. Makes me wonder if its time for you to find a new shop, or if you have some sort of freakish bike.

When I get a chance to I will

I cant imagine how your spokes are that close to your chainstays.
I'm willing to bet your chainstays arent labeled "Fatties Fit Fine" :lol:

This. Fit my Tarmac perfectly. Aside from the issue with the cadence/speed sensor issue, everything else took all of 5 minutes to install perfectly.