In a tracklaying gear with a frame having an idler wheel linear guide in which at least one guide piece holding the idler wheel axle is movable, and on which a tensioning means of a tensioning device supported in the frame can act in the guidance direction, at least one mechanically guided and centered elastomer spring body is installed to bulge under axial compression, such that the spring body can be readjusted, the elastomer spring body consisting of an elastomer material largely incompressible as a spring.