Abstract: A treadmill (10) includes a frame (12) on which are rotatably mounted first and second roller assemblies (14, 16) on axles (40, 48) disposed on spaced apart transverse axes (42, 50). An endless belt (18) is trained about the roller assemblies. A ratcheting bolt assembly (52) is rotatably secured to the frame and is engaged with one end of the second roller assembly (16) to enable adjustment of the tension in the belt. The ratcheting bolt assembly has a threaded end portion (74) that is threadably engaged with one end of the axle on which the second roller assembly is mounted. The ratcheting bolt assembly includes a ratcheting head (80) that is graspable to rotate the adjustment bolt assembly for threadably advancing the axle on the threaded end portion of the adjustment bolt assembly, thereby changing the distance between the first and second roller assemblies and adjusting the tension in the belt.