Originally Posted by
MrClyde
If battery time is a concern, the Forerunners are not a good idea. And the display is pretty small for bike use. They are made to be a cross between running and biking. My brother has a forerunner, I have an Edge 305. On a century, he ran out of battery 4 hours in. Brand new, fully charged unit.
I have used the Edge 305 on 9 hour rides, didn't run out of battery. Haven't done a ride longer than that yet.
I've been happy with my 305. The 500 looks like a good option as well. I don't need mapping, so the 305 does all I need for now.
I have a Forerunner 305 and use it for my bike trips. I originally got it about 4 years ago to use for walking/hiking, but I find it works fine for biking. Yes, the display is smaller than the Edge models, but it's adequate. I did have to by a handlebar mount for it. You can buy the Garmin bike cadence unit and it will pair with the Forrunner 305. I'm not sure about power meters.
Note that the Forerunner 205 model will not do heart rate monitoring (even if you were to buy a heart rate strap).