Do these computer measure distance covered by GPS or by the old style wheel/magnet interface?

I’d like some way to measure how far I’ve gone on a turbo or rollers so GPS would be really pointless here 😀

both if you have the sensor

As Uplink says, you can get one of these, either separately or part of a bundle.

Arhh thanks, so its an extra. Excellent to know.

It seems to be included in a few of their bundles, even better!

either separately or part of a bundle.

It seems to be included in a few of their bundles, even better!

Who knew eh? 😉

more specifically the bundle I was looking at, which was a nice surprise.

http://www.dcrainmaker.com/2010/01/how-to-train-indoors-with-your-garmin.html

This is the thing that impressed me about the garmin 800. I put the rear wheel magnet on.. went for my 1st ride. The garmin beeped at me after 5minutes and showed “wheel size calibrated”

you can also enter the exact wheel circumference in mm into the garmin as well if you do not want auto sizing.