Garmin Cadence/Speed sensor issue

[Daxiet]

Really getting tired of the Garmin glitches, but here goes my problem, anyone had similar or have a viable solution:

 

I was busy with a lengthy ride on Sat, during the ride the speed sensor stopped picking up a couple times, by 130kms the speed sensor no longer worked at all. Cadence was fine, but no more speed readings. Adjusted the speed sensor so that the magnet basically touches the sensor each time is passes and still no joy.

 

The magnet is perfectly aligned with the little line on the speed sensor. I have pulled the battery out and re-inserted, pressed the little white button to test it. Red light comes on for Cadence on each pass, Green light doesn't come on for speed. Can hear the magnetic switch inside the sensor clicking on each pass of the magnet.

 

 

 

[LEACH]

IS THIS ON A GARMIN EDGE 705?

[Fulmenicilus]

If it's the 705 you don't need the speed sensor to work that's combined with the cadence sensor - the normal gps function will give your speed, irrespective of whether or not the speed sensor is working! Thats the beauty of it!

[Daxiet]

 

IS THIS ON A GARMIN EDGE 705?

 

Yes

 

[LEACH]

WITH THE EDGE . .. YOU CAN USE THE SENSOR ONLY 4 CADENCE . . .AND USE THE GPS FUNCTION 4 SPEED READING! . . .EASY !

[Radfahrer]

Batteries?

[Daxiet]

 

If it's the 705 you don't need the speed sensor to work that's combined with the cadence sensor - the normal gps function will give your speed' date=' irrespective of whether or not the speed sensor is working! Thats the beauty of it![/quote']

 

1st - GPS speed is very inaccurate (going through forests results in bad readings, generally a decent drop in reported speed).

2nd - to get it to use GPS speed you need to untick Cadence Sensor in bike profile. Thus I lose the Cadence reading as well as accuarate speed.

 

I did disable the Candence sesnor for the last couple kms, so as to get GPS speed reflected. But still why the need to compensate for faulty/unreliable equipment. These Garmins have Auto Pause, but that has bugs a plenty, it comes with Training Center software which has bugs, there are many other bugs to add to this list. Frustrating that at the price you pay for a 705 it is still under development it would seem.

 

[Radfahrer]

 

1st - GPS speed is very inaccurate (going through forests results in bad readings' date=' generally a decent drop in reported speed).

2nd - to get it to use GPS speed you need to untick Cadence Sensor in bike profile. Thus I lose the Cadence reading as well as accuarate speed.

 

I did disable the Candence sesnor for the last couple kms, so as to get GPS speed reflected. But still why the need to compensate for faulty/unreliable equipment. These Garmins have Auto Pause, but that has bugs a plenty, it comes with Training Center software which has bugs, there are many other bugs to add to this list. Frustrating that at the price you pay for a 705 it is still under development it would seem.

[/quote']

 

I changed my back wheel, the GPS picked up, no problem. Cadence worked No problem. Rode with 3 guys and my speed was exactly the same as theirs.

I didn't untick or change anything, it did everything automatically.

 

Also rode through tress on mtb with gps speed. It was 100% including the maps etc etc.

 

Maybe you got a dud unit

 

[Minion]

 

Was it raining, or had you recently washed you bike/got it wet?

 

Garmin's claims to the contrary, the GSC10 is not waterproof. If you remove the rubber pad at the bottom, you will see a small hole. Water gets in through this hole and starts to corrode the circuit board. It has a particular affinity for a certain small cap (or resistor - I can't remember which).

 

If you feel like searching, there was a post about this on the Motionbased forums (I can post a link only when I get home this evening).

 

The summary is:

 

To seal new units:

1.) Open the cadence sensor

2.) Spray HPA coating (or clear lacquer spray paint) onto the circuit board.

3.) Clean the HPA off the battery and cadence contacts.

4.) Fill the hole with silicone sealant NB: must be not be acid-based sealant (IIR Bostik Bathroom sealant works - will check at home).

5.) Coat the joint between the two casing halves with sealant and close the casing.

 

To repair the old unit requires a replacement cap (or resistor) and some micro-electronic soldering skills. You then repeat the above steps.

 

I used to have problems with the sensor. I opened it up and the cap (or resistor) was indeed corroded. I received a new sensor from Avnic (as part of an unrelated warranty replacement for my Edge) and after sealing it as described, I no longer have problems.

 

Edit: you can use Bostik Mirror sealant or Build Neutral Cure sealant

 

Edman2009-06-11 14:50:08

[Daxiet]

How does it suddenly know you no longer are using the Speed sensor and switch to GPS?

 

I was cruising at one stage at around 40kph then looked down and was suddenly clocking 0kph. I don't see how it would suddenly know to switch to GPS tracking. Perhaps when you first turn the 705 on and it picks up the first rotation of the wheel it enables the Speed sensor for the period that the 705 is on?

 

As for accuarcy, I sometimes use the 705 on my road bike which hasn't got the cadence and speed sensor. Compared to the cycle computer on it and the race organisers distances, the Garmin is roughly short by 3kms / 100kms.

 

Keep in mind for it to calculate your speed, it needs to accuarately calculate your rate of climb or descent/forward speed to get a true speed. Altitude change is never going to be perfectly measured hence it has to make mistakes in speed calculation.

 

 

[Daxiet]

Edman

 

It does have a weekly bath, last bath was the weekend before the issue.

 

If the GSC10 is not water resistant then I think Garmin should remove themselves from the MTB sector. In most races there is bound to be water crossings, considering where the sensor is place it is bound to experience water exposure.

 

But thanks for the info. Things I wish I knew before buying a Garmin.

 

See the Avnic support guys have responded, will see what they have to say.

 

[Minion]

 

As for accuarcy' date=' I sometimes use the 705 on my road bike which hasn't got the cadence and speed sensor. Compared to the cycle computer on it and the race organisers distances, the Garmin is roughly short by 3kms / 100kms.[/quote']

This is more likely a calibration issue on your cycle computer. I measured the rollout on the wheel of my bike and input this value into my Polar. It gave readings within 0.1% of my Garmin over 100km on the road.

As for race distances, I have ridden only one race where the the race distance was actually the same length as that published. The rest have all been shorter (even when compared to measurement taken directly from a map).

 

Keep in mind for it to calculate your

speed' date=' it needs to accuarately calculate your rate of climb or

descent/forward speed to get a true speed. Altitude change is never

going to be perfectly measured hence it has to make mistakes in speed

calculation.[/quote']

I think this is a non-issue. On a 10% gradient, the difference between horizontal distance travelled and actual distance is less than 0.5% (100m vs. 100.499m)

 

[Daxiet]

Wow, Avnic support tell me the GSC10 is not used to pickup speed, says the unit only uses GPS for speed tracking....

 

They must have provided me with the spoke mount magnet just to balance my rear wheel. Plus the manual to setup the GSC10 must be wrong, because it clearly tells you how to setup the speed sensor which according to Avnic doesn't exist.                               

 

[Minion]

 

If the GSC10 is not water resistant then I think Garmin should remove themselves from the MTB sector. In most races there is bound to be water crossings' date=' considering where the sensor is place it is bound to experience water exposure.

 

[/quote']

I agree. Overall, I think my Edge was worth it, but there are some places where they really dropped the ball (the handlebar mount failures are another one).

 

I've got a new cadence sensor on its way from Kalahari.net. When it arrives, I'll post some pics of the waterproofing modifications.

 

[Daxiet]

 

Edman,

 

Yes the more I think about it the more I am inclined to agree the % error on GPS reading is negligable (however tree issue definetly noted a decline on speed entering over grown areas, rectified upon exit). Plus I know most races distances are never spot on.

 

That said, I am tired of compensating for bugs that shouldn't be there on the Garmin. But can see I am going to have to drop the use of the speed sensor on my GSC10. Yet another compromise.

 

Daxiet2009-06-11 01:42:45

[Schwynn]

Switch the 705 on.

 

Wait for it to boot.

 

Press menu button, bottom right.

 

Go to Settings

 

In Setup Menu, goto Profile & Zones

 

In Profile goto Bike PROFILE

 

In Bike scroll down to Cadence, tick the block

 

Scroll down to Wheel size, Select Auto

 

On left bottom, press mode repeatedly until you see data screen.

 

Your'e good to go!!

 

Sorry forgot to mention. I never take my cadence sensors of any of my bikes. Never had any probs with them. I also do not drown them with water!!Schwynn2009-06-11 01:43:57