I like to hear my GPS talk me through the turns. This is especially helpful if the summer sun washes out your GPS screen so badly you can't see it. But it can also be difficult to hear the little GPS speaker at higher speeds wearing a fullface helmet. Bottom line: I won't buy a GPS for my bike unless it has an earphone jack... and NOT MANY of them do.
I had a Tom Tom One XL that I used in my car, and I liked its verstility. But it didn't have an audio jack, so I had to open it up and install one. Since I'm often wearing earbuds for my iPod when I ride, I wired a stereo phone jack into the mono GPS speaker circuit. I only wired to one channel, and I only get the GPS voice in one ear, but I don't have to use a special mono earplug when I want to hook up to my GPS.
Last edited by xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxoldebikerfarte; 12-21-2009 at 09:11 PM.