Garmin Wheel Diameter Settings

AlanW · Post by **AlanW** » 31 Dec 2014 20:41

Ever since I have had my Edge 500 I have had the wheel circumference settings mode on "auto", including when using it on my turbo. However, it has just been suggested to me that I should really be using it in the "manual" mode, and then inputting the wheel circumference relevant wheel diameter onto the device, in my case 2105 for a 700c x 25 wheel/tyre combo

Is that right?

So if that is correct, then do you have to keep switching from "auto" to "manual" wheel circumference each time you use it on a trainer?

Page 43 and 51 - HERE

Or select "manual" and input 2105 and then switch it back to "auto" mode?

Andy Terry · Post by **Andy Terry** » 31 Dec 2014 22:09

Seems to me you can stick it in manual mode, enter the value and leave it.

Worth a a try, maybe.

AlanW · Post by **AlanW** » 31 Dec 2014 22:38

Andy Terry wrote:Seems to me you can stick it in manual mode, enter the value and leave it.

Worth a a try, maybe.

Yes, thats exactly what I was thinking Andy to be honest?

jdtate101 · Post by **jdtate101** » 02 Jan 2015 12:19

You can always setup another "bike" on the garmin specifically for the turbo if needed. Ie Auto for turbo but manual for road, that's what i do. all my garmin 'bikes' have manual wheel entries as the roadbike is very different to the cx and I've found the auto to be a little off. It only matters if you're using a speed sensor, if you're just using the GPS to do speed then just leave it on auto for everything.

Patch · Post by **Patch** » 02 Jan 2015 16:44

If your using auto on the turbo then the garmin won't be able to work it out because your not moving. So it should be on manual for turbo use. I have mine on manual all the time it doesn't affect GPs performance.

laurence_cooley · Post by **laurence_cooley** » 02 Jan 2015 17:05

Won't it just retain the wheel size setting that it auto'd to when you were last outside though?

AlanW · Post by **AlanW** » 02 Jan 2015 17:44

Patch wrote:If your using auto on the turbo then the garmin won't be able to work it out because your not moving. So it should be on manual for turbo use. I have mine on manual all the time it doesn't affect GPs performance.

Yes in theory I would agree with you 100% Chris. However, what confuses me is that I have never ever had my Garmin set on any other setting other than auto, and as you will see from all my turbo sessions on Strava, its picking the speed and distance from somewhere?

Unless as Laurence has suggested, it retains the wheel size settings?

Just as a matter of interest, but when I went out yesterday, I had both my Garmins running again as a test. The Edge 500 was set to manual at 2150 wheel circumference and the Edge Touring set to auto (you cannot do manual anyway I dont think?) The average speed and also the distance ridden were exactly the same when I downloaded both .gpx files.

Andy Terry · Post by **Andy Terry** » 02 Jan 2015 18:00

Why don't you get an old-style computer (calibrated to 2105) and see what it says. IMO (if correctly set up) this is the most accurate method for distance, average speed and maximum speed.