I have my new Garmin Montana mounted on my woods bike using the Garmin "rugged" mount - rubber mounted to my handlebars. I have about 300-400km on it - all backroads and single track. Its now starting to randomly power off. For a while it was saying "do not recognize battery" - when I have the lithium battery installed (and still on the rugged mount ?!?!). So I put in AAA cells and mounted it on the rugged mount. I would still randomly shut off. Back home, on the table - it of course works just fine. (grumble grumble). *sigh* I had these problems with my 60CSX - I was hoping the Montana could handle it better.