I'll start off saying I was riding a 7.2FX with the stock platform pedals. Today on my ride around 10 miles I started to feel a slight thump under my left foot that was coming from the pedal. It was occuring at the top of my stroke. Not sure really how to describe other than to say it kind of felt like someone was flicking my foot where it was on the pedal. I got off the bike and checked the pedal- everything felt good tight and good. The pedal would spin freely when I checked that. I have no clue what this could have been, any help is appreciated.