This post is excellent! It turned a rigid aluminum MTB frame into a real pleasure to ride. For reference I weight 140lbs and have a 300mm distance from the seat tube top edge to the seat rails. The post flexes enough to take the edge off the rear-end without feeling mushy or anything. It has significantly improved the bike's ride-ability over harsh bumps. It really transformed the frame into a pleasure to use - and I ride hard and fast. By a pleasure I mean it allows the frame to perform like an aluminum frame (stiff and efficient) without being harsh. Much more like a higher-end frame than it was.