After a few 15 mile rides these old legs felt up to a 20 miler so I gave it a shot and it really felt good. In all honesty, my legs felt stronger after this trip than they did after my first 5 miler. I can see 25 miles coming over the horizon! YEEEEEHAAAW!
UPDATE: TWENTY FIVE MILES TODAY!! All I can say is HO-CHEE-MAMA!, WOWYZOWY!, OMG! & GADZOOKS!! The 12.5 miles due east of Oakdale (CA) on Hiway 120 is a hill climbers dream but it just about killed this old fart! OK, that's a BIT of an exaggeration but it sure as heck did test my mettle. One really strange thing is that while I rode 12.5 miles east, when I turned around and headed home I must've taken the short rout 'cuz at my front door the odometer read only 24.88 miles! Anyway, it was a good test of my endurance and I'll probably stick with that for awhile or go back to flat land riding.