JAJ0404

I just installed my Garmin cadence sensor, but it never asked for my wheel size. Where do I enter this? I took the bike down the street, and the cadence seemed to be working, but it's the first time I've had cadence so I have no idea how accurate it is, have no feel for it, but the results seemed reasonable. But how can it calculate anything with no wheel size?

contango 

Isn't cadence how fast you spin the pedals? Unless I'm missing something it's not a function of your wheel size.

byte_speed

It will compute the wheel size from the GPS data while riding, which is what I do. There is a place to enter the tire size, under bike options, I think.

My Garmin 500 only seems to use the wheel sensor if there is no GPS reception whatever, so I don't worry too much about the wheels size.

JAJ0404

Thanks - I guess I should have completed the Garmin set up before trying the cadence. Found it.

JAJ0404

Of course you're right, I've been waiting on my Garmin to arrive for about a week and I guess I'm all giddy that it's finally here and I'm having a blonde moment trying to get it all set up to ride in the morning.

dblackwood72

The cadence sensor will give you your pedal rpm and your mph.

simonaway427

No. The cadence PORTION of the GSC10 will provide cadence data - the other PORTION of the GSC10 provides speed data. For the speed to be accurate, you must enter the size of the wheel, or have the Garmin do it for you via GPS. THe wheel size has nothing to do with the cadence data.

vandalarchitect

So I've heard various people say this but my question, is how do you know? According to Garmin, "All the Garmin fitness devices records speed and distance using the GPS satellites except when the fitness device is using the GSC 10. When using the GSC 10 on the fitness device the distance and speed information come from the GSC 10 instead of the GPS info." Source

+1

RollCNY

The wheel size setting overrides the GPS. I ride with a 500 and GSC10, friend rides with 500 and no GSC10. We noticed speed discrepancies, especially on downhills, so we conducted a test. I set the wheel size in settings ridiculously small, and watched my speed get cut proportionally when riding beside him, as compared to his GPS measured speed.

canam73

I did an accidental test that also proved that the GSC10 will over ride GPS data. I knocked the spoke magnet partially out of alignment while fixing a flat. For the rest of the ride the speed data was wacky but when I loaded the ride the tracking and timing were spot on.