Originally Posted by Cycle_of_life

On the low end, what I thought was 5 miles per hour turned out to actually be about 8 miles per hour, and at top end, what I was sure was about 25mph turned out to be 17.2mph.

When I was going 17mph, I wasn't peddling as hard as I could; I had some reserve left, but it surprised me that I wasn't even doing 20mph.

I'm in my 50s, in good shape, and I'm riding a Trek 820, which I'm learning from reading various threads here, is a bit on the heavy side, and not really made for speed.

I'm not really interested in going fast, it's just that after finally having a speedometer, and being on a flat highway that doesn't have many cars, and traffic lights every mile or so, I wanted to see what I, and the bike could do.

Is this low top speed common for my situation?