I have encountered something strange on my last two rides. It feels like there may be a flat spot on my rear wheel. It's hard to explain but I can really feel it on the smoother roads. It feels like a thumping on each revelution or maybe a small hesitation. Gets kind of uncomfortable on descents. That being said. The ride before this started I flatted less then a mile from home and changed the tube. Didn't notice it on the last mile as I was crawling back because I was beat. Subsequent rides it has been very noticeable. I even replaced the tube that I put it because I flatted again on my last ride(I guess I didn't get everything out from the first flat). I thought maybe I installed the tube wrong the first time because I did it quickly and just wanted to get home. Has anyone ever experienced anything like this? Thanks.