Thudbuster Long Travel (LT) The Thudbuster Parallel Linkage technology stays in the direct path of the natural travel of the rear wheelùas a bump lifts the back of a bicycle, the rear wheel pushes up and forward into the rider The Thudbuster works by compressing along the exact opposite pathù down and rearward ùabsorbing force at the same rate Natural suspension feel without being overly active and allows for more travel without compromising pedaling position 90 mm / 3.5ö of travel 5 mm (unweighted) setback Medium firm elastomer pre-installed from the factory. SEAT POST G4 TB 30.9 LT