Etrex capacity

[rb58]

Hi. I have 4 day rides (routes and tracks for all four) loaded on my eTrex. I've now completed 2 and the Etrex is telling me the track log is 54% full. As the next two rides are longer than the first two it seems there may not be enough storage space to record them. It's a Garmin City Navigator SD card. Is this normal, or is there a setting I can 'tweak' to allow it to store more. Considering these 4 rides together are only 330 miles, the Etrex isn't going to be much use recording, for example, a 600km Audax, LEL 2013, or indeed next week's 8 day LonJog - although I'm sure others do use them for such things.
Thanks

 

[ianrauk]

Has it got an option for smart recording rather then every second recording?