I did my first group ride about a week ago. The website of the LBS said 12-14 MPH average and 50 miles. The week previous I did 13.8 MPH over 37 miles so I thought I could buck up and do the extra 13 miles... Yeah, those guys were doing 18-20 MPH and were quite comfortable climbing....I wasn't and I'm a big fatty at 270 so while I could keep up on the flats, they lost me on the hills every time. YMMV