Garmin GSC10 cadence/speed sensor

... distance calibration?

18 messages
05/11/2011 at 11:57

I just got a Garmin GSC10 cadence/speed sensor for my bike ... don't have a pproper bike computer so thought this was the easiest way, by linking up to my "running" Garmin watch. I need to set the wheel size on the watch to get the calibration correct ... I'm assuming this is based on where the sensing magnet ends on the wheel and not the actual wheel size. Bit confused as some forum messages seem to suggest using actual wheel size which doesn't make sense to me ... presume the device calculates wheel rpm and then converts to distance.

Rc.    pirate
05/11/2011 at 12:26

If you have a garmin that has satellite then that would sort your distance would it not?

If using the bike on a turbo indoors then and wanting to measure your distance/speed etc then you need the sensor, if not then I wouldnt bother tbh, hth

Trogs    pirate
05/11/2011 at 13:59

Yes, the GSC10 calculates distance by counting wheel revolutions. It doesn't matter where on the spoke the magnet sits, it will only pass the device once in every full revolution of the wheel. Set it for your wheel size.

I think I read somewhere that when outside, if you have a GSC, the garmin will use that to measure distance over the GPS and is more acurate, particularly on hilly routes.

Plum    pirate
05/11/2011 at 14:14
As Trogs said,,,,,It counts the revolutions and knows the distance travelled because the wheel size you enter (probably 700 on a road bike) sets the circumference of the wheel

05/11/2011 at 14:18

I think that when the sensor is detected, it will be used. If the sensor disappears, the Garmin will pick the GPS. Someone on the Garmin website said the sensor or GPS would be the same on the road but the sensor would be better for measuring off-road. You'll notice if your Garmin goes into Autopause and/or you have a few zero speeds patches on Garmin Connect it could be relying on the sensor. 

This may help too https://forums.garmin.com/showthread.php?t=23498&highlight=size+cadence+wheel+sensor&page=2

Edited: 05/11/2011 at 14:18
IronCat5    pirate
05/11/2011 at 22:09
Set it to auto, go out for a ride. Job done.
06/11/2011 at 08:22
Trogs. wrote (see)
Yes, the GSC10 calculates distance by counting wheel revolutions. It doesn't matter where on the spoke the magnet sits, it will only pass the device once in every full revolution of the wheel. Set it for your wheel size.


Of course ... a revolution is a revolution, no matter where the magnet is. Doh!

Thanks everyone ... btw, my Garmin is not a sat nav version - i have a calibrated foot-pod.

06/11/2011 at 09:07
Don't forget to take your tyre size into account when setting the wheel size on your Garmin. This doc has a list of wheel and tyre sizes on page 50 - http://static.garmincdn.com/pumac/Edge_800_OM_EN.pdf
07/11/2011 at 13:09
Works well ... Mapmyrun commute distance to work = 5.04M ... GSC10 distance = 5.04M. Can't complain.
16/10/2012 at 19:15

The problem with using GPS to calibrate the wheel rotation sensor is that GPS isn't terribly accurate a lot of the time (+/- 2% in Garmin implementations) and can be worse under some conditions (and yes of course, sometimes it can be pretty much spot on, but you never know when. Why not take away the mystery and just bang in the correct value manually? - Garmin have all the details in this table.

The Evil Pixie    pirate
16/10/2012 at 19:24

mine does the cadence but not distance when on the turbo

is it 'cos it tried to get a GPS signal - should I turn that off before I start going?

16/10/2012 at 20:04

First of all, have you set up the bike profile on your device? 

Doner Kebab    pirate
16/10/2012 at 20:39

yes EP turn it off or when you load up garmin connect or something you will have a squiggle going round your living room and a crap distance because the satelites have a hard time triangulating through walls  

 

 

16/10/2012 at 20:50
Doner Kebab wrote (see)

yes EP turn it off or when you load up garmin connect or something you will have a squiggle going round your living room and a crap distance because the satelites have a hard time triangulating through walls  

I keep one near the telly to sort that issue out

If you can't afford a geo-stationary GPS satellite in your front room*, you can also turn off the GPS status on your Garmin device, if it hasn't already asked you if you are indoors. That way, no confusion with the speed sensor on the bike.

*Thinking of upgrading mine to a European Gallileo satellite soon

The Evil Pixie    pirate
16/10/2012 at 21:21

so that means I'm going to have to get on the turbo again tomorrow

turn the garmin on in the house - switch the GPS off, switch to bike then go outside to the garage

This the problem is that when in the garage it gets a flakey signal so tries to track me (sent me down the road this morning) I did turn the GPS mid session this morning but it still didn't record the distance only cadence grrrr

meface    pirate
16/10/2012 at 22:22

You can turn the GPS off in the garage.

Mode Button, GPS, Status, Off.

If you haven't set a wheel diameter/circumference thingy then it can only count cadence becuase it doesn't know how big the wheel is.

16/10/2012 at 22:34
m..eface wrote (see)

If you haven't set a wheel diameter/circumference thingy then it can only count cadence becuase it doesn't know how big the wheel is.

That's what I was trying to determine first m.eface; that the bike profile was in the device so that it knew the distance of one revolution of the wheel and could therefore work out total distance when on the turbo

The Evil Pixie    pirate
17/10/2012 at 06:40

hmmm cadence OK and working but not distance (used cateye for that)

my wheel was set to auto so have changed this to tiny 1650mm cos I have tiny bike with silly tiny wheels and will try again!!

Was going to rest today as have long day but wanted to test it.

Was going to rest tomorrow due to long day today but may have to play!!


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