When I come back after my 10mi. ride at 10mph I am pretty tired but not totally exhausted. If I push too hard it isn't fun anymore. I have to exert a fair amount to keep a 10mph average and my thighs burn after getting off the bike. I ride a little slower when my wife joins me but the other day she decided to push and over did it. I did NOT encourage her to go faster, she just thought it would be fun to drop me for a few miles so she did and the next day she was hurting. I guess I could average 11mph for ten miles but then I'd be the one that was hurting and not wanting to ride the next day. I didn't have the computer when I started but I'd guess my average speed back in April was 8 mph and I thought that was pretty good until I started hanging out on BF