I started training on the velodrome recently with, obviously, a fixed gear track bike. After a couple of days in a row, I got on my road bike to do a training ride over some local mountains. While spinning downhill after just starting out, I noticed what felt like a stickiness in the pedal stroke. Like I was getting mechanical resistance from inside the bottom bracket. I pulled over and tested it on the side of the road but didn't nontice anything. I'm wondering if this is due to the transition from fixed gear to freewheel again? Or if there is something really wrong with my bike. Next step is to take it in to be looked at. It only seemed noticeable when spinning at a high RPM.