I am not an expert, but people claimed a size smaller frame actually works better for a 29er. They said that if you are riding a Large hardtail 19-19.5″ in a 26″ wheeled frame, you must consider a Medium 29er (size: 18″). Any help would be greatly appreciated! I am 180 cm tall and want to buy my first 29er. What size should be the most aappropriate - Large or Medium?