Hello Fellow Clydesdales....47yr old big guy....and i fluctuate between 210 and 225 depending on season and schedule. I generally get to ride 6-7 days a week spring through mid fall, and weight drops to about 210. However, although i'm a slow rider (14-18 average), I can't seem to build enough endurance to ride more than 35 miles (about two hours) at a time (generally I ride straight through, no stops). Any help to build my endurance to ride longer and further? I'm not looking to increase speed as much as I am to increase the time of the ride.