paisan

+1 Well said

Rimmer

Strava automatically removes stopped time with auto-pause off. TrainingPeaks recommends turning it off. I haven't tried these third party tools yet.

TrojanHorse

Son of a ***! So today the damn speed sensor decides to take a holiday for about 4 miles and the garmin thinks I only rode 30 miles.

To me, auto-pause on, auto-pause off is decidedly secondary to getting REASONABLY accurate data on my ride. I fiddled with it again, it sort of worked again, but then kept auto-pausing, so I turned it off and off it stays. I'm done with that feature and frankly, average speed is irrelevant unless you're riding the same patch of asphalt every time anyway.

So after a while the speed came back on all by itself but it fluctuated up and down like it was GPS speed, not wheel sensor speed. I was maintaining a rock steady pace (cadence wasn't changing at all) but the speed went up and down by a half mile per hour. Does anybody at Garmin actually use these things? Crikey.

I did try the cue sheet part today and that was really cool... went on a large group ride and of course, we stayed together for a while but I never grabbed a cue sheet at the start - my garmin kept me on track. It has a tendency to make the turns look further away, and tell you "oops, missed your turn" as you're riding through the intersection, but with a little attention it worked well anyway.

sstorkel

Sounds like you need to either:

1) Replace the battery in your GSC-10

or

2) Have someone check your install/placement of the GSC-10. Again, it's more important to have reliable speed information than cadence if you're forced to chose between the two

or

3) Have Garmin send you another GSC-10

Aside from having to replace the battery in a every brand-new GSC-10 that I've purchased, mine have been rock-solid reliable...

TrojanHorse

Well, I have two spare batteries for that thing I just bought so that's the next remedy I'll try.

Rimmer

Just curious does an almost dead or weak battery show any symptoms or were your batteries always dead? I installed my sensor last July, and I never had any problems with it other than the one time it moved slightly on the chain stay away from the pedal magnet on the crank arm. This caused the cadence not to show. Re-positioning it fixed it.

TrojanHorse

The one that was IN my speed sensor read 3.0 volts on a multi-meter. The new one I put in read nearly 3.3 v. You really can't judge a battery's capacity on voltage but a good condition battery should display full voltage on a voltmeter.

I also just noticed that the little speed sensor arm thing moves. I think I'm going to flip the sensor upside down, I just don't like the idea of the spokes moving INTO the sensor arm... if there's any contact, iI'd rather have the motion of the spoke knock the speed sensor arm over.

Oy, I'd love to spend 15 minutes with the dweebs that wrote the software for this thing, I've never had so many WTF moments with a new piece of electronics ever.

Apiltas

Golden Cheetah is a nice little find I'd never heard of before, I use primarily Linux. Thanks for the tip.

sjvcycler

I've never had any issues. You have to hold reset down and wait for it to clear the ride to start a new ride.

sstorkel

In my case, I had inconsistent results from the speed/cadence displays. Sometimes, for example, cadence would come in and out over the course of a ride. Other times I'd be spinning like mad (110+rpm for me) and the display would report only 40-50rpm. When I swapped in a new battery, I also noticed that the test LED was quite a bit brighter.

sstorkel

How could the spoke move into the sensor arm? The GSC-10 should be installed on the top of the left chain stay. If should be positioned on the stay such that it ends up between the front of the rim and the hub. The angle between the arm and the body of the sensor shouldn't be greater than 90 degrees. Something like this:



In this position, if a spoke were to hit the arm somehow, the arm would be knocked against the chain stay and the wheel would continue to rotate...

dehoff

That would be the smart way to install it, but a GIS reveals this as the second image:


Garmin GSC 10 Speed/Cadence sensor by mikkelz, on Flickr

TrojanHorse

That second image is exactly what mine would have to look like, right down to the logo on the chain stay . The chain stays are very shaped (hard to see in that image, but they are) - there's barely any room between the chain stay and the wheel where the braking surface is, which complicates the install in two ways - the cadence sensor is further away from the crank, which also has a slight curve to it (which is why I glued that extra magnet on) and the speed sensor is so close to the spokes no matter what I do with it that it strikes the spokes with the slightest misalignment.

If I flip it, any physical contact will have the effect of pushing the GSC-10 arm further away - that's what I meant by that.

I used it sensor free tonight and it was dead on. I also killed the auto pause and I got an overall speed and a moving speed and THAT was dead on. I do want cadence though, so I'll keep fiddling but I generally know about where I am in the range anyway.

I was very happy with it tonight though.

sstorkel

So, it sounds like what you're trying to do is put the speed sensor magnet as close to the rim as possible? That may not be the best placement.

My bike is also has minimal clearance near the brake track. Luckily, my chain stays bulge out as they approach the wheel hub. I have the cadence magnet perched, literally, behind the pedal spindle on the crank arm. The magnet for the speed sensor is about 1/3rd of the way down the spoke from the rim. This positions the sensor on the chain stay in a place which gives decent clearance between the sensor arm and the spokes, without having to flip the arm up like the picture that dehoff posted. I don't have a ton of extra room, but I've never had a spoke contact the sensor arm...

bike_boy

Some folks have had better luck using "rare earth" type magnets with the Garmin GSC-10 speed/cadence sensor. This type magnet is quite strong; so this magnet can be smaller in size, if need be. (from what I have read)

TrojanHorse

I have the cadence magnet just barely in "front" of the pedal axle right now but the chain stays don't really start swooping back out to accommodate the hub until after the pedal. I'm not whacking my heels on the chainstays with this bike, which is great.

Even with a double thick magnet, I had to slightly tilt the sensor towards the crank to get a good cadence reading.

After fidding with it some more tonight, I'm not sure if I have it mounted securely enough to prevent any motion while riding. I think I need another rubber strip for the opposite side so the zip ties don't slide - the diameter of the chain stay gets smaller towards the dropouts, so with sufficient vibration, the sensor wants to walk backwards. I'm not sure that's what happened but it's a theory.

tergal

@Trojanhorse , what type of magnet are you using? MY cheapo unit was having drop outs a lot so i added a magnet on to the stock one .

The thing is i used a HDD magnet which are neodymium magnets it is able to pick up a large spanner or two

IF you have a old HDD around open it and take the magnet out, Then break it in half to give that a try. If that doesn't give you a constant signal well i have some stronger ones here i can mail you .

TrojanHorse

Ooh, didn't even think of stripping an HDD - I have a small basket of them floating around.

I stole the cadence magnet from my old cateye and stacked it on top of the GSC-10 magnet. I bought some magnets from Radio Shack but the ceramic ones stunk and the rare earth ones were too small.

tergal

Hdd magnets are the best and they are brittle so just lay it on concrete and give it a tap with the hammer to make smaller very sharp magnets.

Mithrandir

Love my Edge 500.

However that being said, here's something that may help you. When I first got it I used it on my mountain bike which had stays and pedals that were really tightly grouped and had no problems with the GSC10 sensor. But when I got my road bike, everything was wider, especially the crank-arm-to-chainstay distance. The GSC10 just could not get reliable readings, no matter how awkwardly I angled the sensor. As it turns out, the magnets that the GSC10 come with are just too weak. I bought a pack of Neodymium 1/2"x1/8" circular magnets from Amazon (https://www.amazon.com/gp/product/B00...00_i00_details) and since my pedal spindles are steel, they are magnetic, and the magnet neatly snaps into place along the pedal axle. Don't need to glue it or tape it or anything, been using it this way for 6 months and it has yet to fall off. The new magnet is strong enough that I can move the sensor closer to the wheel magnet. Flawless readings every time now. Try it out.

TrojanHorse

Ordered.

Thanks for the link. My cranks aren't steel but with a tiny amount of glue they should stick right on top of the existing cadence sensor.

Seattle Forrest

It sounds like yours is about as accurate as mine. I said to hell with the speed sensor, and get speed and distance from the GPS. It's sad that that's more accurate than counting how many times the wheel moves, but ... I just want data I can use.

I never tried rare earth magnets or anything. I assume the one that came with the thing works well enough, and, since mine doesn't, I think the problem is more likely to be the Garmin itself.

TrojanHorse

Well, I've been riding without the speed sensor and I do miss the cadence a little. I ordered a bushel of rare earth magnets from Amazon just now, so I'll try that. I also replaced the battery, I just haven't had a spare hour to fiddle with the sensor. As far as I can tell, you can't have the magnet too CLOSE to the sensor and you can't have it too far away, so my crank was too far away and teh wheel was practically hitting the sensor, so adding a magnet or two may allow me to screw with the sensor positioning a little more.

I should have about 12 leftover magnets if you want to try it.

bigfred 

Just to restore some hope to those who might be considering an Edge 500 and GSC10. Mine was purchased for me, new, in December. I haven't had an issue with it other than the high cadence readings as a result of coasting with left crank horizontal and trailing. On mine the GSC seems to tolerate gaps of up to about 10mm from both crank and wheel magnets. I certainly didn't spend more than 5 minutes installing the sensor and both magnets. And, haven't had an issue with them since. Other than the magnet once sliding up or down the spoke during transport in the back of the car.