an endless track assembly that mounts to a wheeled vehicle . the assembly provides 1 ) a track suspension having fixed or adjustable , independently biased sets of idler wheels to vary the track contour without affecting track tension , 2 ) an eccentric bearing housing at a drive sprocket controls track tension , 3 ) a contoured peripheral edge at the drive sprocket prevents ice and mud buildup , 4 ) rubber - coated , plastic idler wheels facilitate track movement , 5 ) a multi - vehicle compatible adapter mounting plate accommodates a variety of vehicles , 6 ) a rotation limited torsion coupler and / or rotation limiting coupler arms prevent track contact with the vehicle , 7 ) a locking steering arm coupler prevents loss of steering control , and 8 ) shaped track lugs and channels clear and direct debris away from the track suspension and drive assembly . the improved suspension particularly supports sets of idler wheels in pivotal relation to the track support frame and resiliently biases a pre - tensioned rocker arm that links adjacent suspension arms mounted to the adjoining idler wheels . suspension arm movement induces expansion and contraction of tension springs coupled to the rocker arms to augments shape changes at the track contact surface to optimize traction and steering control .