53 y/o 5'8" 237
Trek 2.3 road bike with clip-less pedals
Only electronics is Droid phone with Cardio Trainer (tracks miles/calories/speed)
Less than 2 months biking experience

I went my longest today, 45 miles of fun flat riding. At about 18 miles a father and son passed me. I sped up and rode with them for about 15 miles. It seemed it was actually easier or I'll just say better riding quicker. They pulled off the path and I kept going but soon fell back into my slower pace.

On my 11 mile round trip work commute I'm up to 12.7 MPH. On the 45 miler I slipped down to 11 MPH. The last 7 or so miles was very slow as I was tiring a bit.

I don't have a system for picking a gear. I just plod along at whatever feels right.

I've read I should be at a certain RPM range and I guess you maintain that range with gearing? If this is correct, how do you monitor your RPM?

Thanks!