On “average terrain” I probably travel at about average speed…
Honestly the cobblers posted up for people “average” performances is barely worth paying attention to, Yes rider ‘A’ might only average 10mph on his regular rides while Rider ‘B’ manages 15mph but for all you know ‘A’ in stomping up 40 miles worth of climbs in the lakes on a DH bike while ‘B’ is mincing around billard table flat roads on a TT machine…
Better to look at how many miles you clock up na devery once in a while time yourself over a “Benchmark” loop to see if you are getting any faster…