Thudbuster

Technology

The Key: Working in the direct path of the natural travel of the rear wheel.

The inherent dynamics of a bicycle create a rocking motion, meaning each end arcs around the other end. Specifically, the rear wheel moves on an arc that has the front axle as its center, and the front wheel moves on an arc that has the rear axle as its center.

As a bump lifts the rear wheel, the rear wheel pushes the saddle up and forward into the rider. The Thudbuster compresses along the exact opposite path (downward, rearward) to absorb force. The Thudbuster moves down and back at the same rate as the bump comes up and forward, so the net movement of the saddle is zero.

Telescoping suspension seatposts have a compression stroke in the vertical plane. As the bump force travels up and forward through the rear wheel, the seatpost suspension is more than 50 degrees out of line with the bump forces. Since 90 degrees out of line is complete mechanical lockout, telescoping seatposts are halfway to lockout by design. This is much less efficient than the fully active Thudbuster design.