A track system (16 i) for traction of a vehicle, the track system comprising: - a track to engage the ground, the track comprising elastomeric material, a ground-engaging outer side, an inner side opposite to the ground-engaging outer side, and lateral edges (31 1, 31 2); and - a track-engaging arrangement to drive and guide the track around the track-engaging arrangement, the track-engaging arrangement comprising: - a drive wheel to impart movement to the track; - a leading idler wheel and a trailing idler wheel spaced apart in a longitudinal direction of the track system, a distance between an axis of rotation of the drive wheel and an axis of rotation of the leading idler wheel being different from a distance between the axis of rotation of the drive wheel and an axis of rotation of the trailing idler wheel; - a plurality of roller wheels (28 1,-28 10) between the leading idler wheel and the trailing idler wheel; - a frame supporting the leading idler wheel, the trailing idler wheel, and the roller wheels, the frame being free of supporting structure for the roller wheels between the roller wheels and the lateral edges of the track; characterized in that the track-engaging arrangement further comprises a mount for resiliently interconnecting the frame of the track system and a frame of the vehicle. - a track to engage the ground, the track comprising elastomeric material, a ground-engaging outer side, an inner side opposite to the ground-engaging outer side, and lateral edges (31 1, 31 2); and - a track-engaging arrangement to drive and guide the track around the track-engaging arrangement, the track-engaging arrangement comprising: - a drive wheel to impart movement to the track; - a leading idler wheel and a trailing idler wheel spaced apart in a longitudinal direction of the track system, a distance between an axis of rotation of the drive wheel and an axis of rotation of the leading idler wheel being different from a distance between the axis of rotation of the drive wheel and an axis of rotation of the trailing idler wheel; - a plurality of roller wheels (28 1,-28 10) between the leading idler wheel and the trailing idler wheel; - a frame supporting the leading idler wheel, the trailing idler wheel, and the roller wheels, the frame being free of supporting structure for the roller wheels between the roller wheels and the lateral edges of the track; characterized in that the track-engaging arrangement further comprises a mount for resiliently interconnecting the frame of the track system and a frame of the vehicle. - a drive wheel to impart movement to the track; - a leading idler wheel and a trailing idler wheel spaced apart in a longitudinal direction of the track system, a distance between an axis of rotation of the drive wheel and an axis of rotation of the leading idler wheel being different from a distance between the axis of rotation of the drive wheel and an axis of rotation of the trailing idler wheel; - a plurality of roller wheels (28 1,-28 10) between the leading idler wheel and the trailing idler wheel; - a frame supporting the leading idler wheel, the trailing idler wheel, and the roller wheels, the frame being free of supporting structure for the roller wheels between the roller wheels and the lateral edges of the track;