42, 6'2", 189lbs. 370 miles/month on the average. Riding a 03 Zurich for 13 months, mountain biked 4-5 years previous.
A lot of variables; From start (roll out) to finish (cool down), stop lights, pee breaks, etc.
Base average is about 17 mph for my 35-45 mile rides. Some of my 50 milers have been 15.9-17.8mph.
Some of my 25 mile climbing routes are 14.8-15.3mph.
These are all solo rides.
On the flats I'll be cruising along at 25+, but I can't keep that average with the hills and stops and I don't have the heart/lung and legs...yet
I did a 60 mile race and averaged 20.9mph with some group hook-ups.
A year ago my averages were about 16.5mph, but I was only riding 20-25 miles.

Trying to get up the endurance and strength to keep a solid 18mph, solo, for 50+ miles. It's hard trying to keep the heart rate averaging below 80% max with a few runs into the mid to high 80s for hills.

Maybe a new bike in February. Serrota Legend Ti.