A track system configured to be mounted to a vehicle comprises a drive wheel, a frame assembly, front and rear idler wheels respectively pivotally mounted at the front and rear extremities of the track system, road wheels pivotally mounted along the length of the track system, between the front and rear idler wheels, and an endless traction band disposed about the drive wheel, the idler wheels and the road wheels. The idler wheels and the road wheels are pivotally mounted on tandem frames such that adjacent tandem frames are overlapping. The tandem frames are pivotally mounted to the frame assembly via longitudinally spaced pivoting points.