GPS vs Cycle Computer

[crossy]

Laying in bed not being able to sleep this thought came to me. If I compared a cycle computer to a GPS device over the same route and distance on a hilly route. Would they read the same distance. As the cycle computer runs on the revolutions of the wheel of the bicycle. Does the GPS just do from a to b and give a different distance. The reason I' m asking is that I have 5 bikes now and I was going to use a Garmin 305 instead of a cycle computer.

 

[adscrim]

I have a cateye velo 5 on my commuter/winter bike but I also put on an edge 305 when doing longer runs on it. In direct comparison, the edge records shorter distances - losing something in the region of 1 mile in 20 vs the cateye. But then, the roads round here are twisty and I think the variance may be less on areas with longer stretches of straight road. In my opinion, the variance is acceptable as the edge 305 is an excellent piece of hardware.

 

[zacklaws]

This subject has been done a little while ago, but I have just got back in from the club ride, my Garmin Edge has recorded 36.97 miles and my VDO C4 37.08 miles which is just a tad over a tenth of a mile difference which is about normal for all my rides and nothing to worry about.This is on a twisty hilly ride.

 

[crossy]

Thanks for your replies I think I can live with that little bit of differece.