Variable track chassis for agricultural machinery, extending, from front to rear, in a longitudinal direction and, from right to left in a transverse direction, perpendicular to the longitudinal direction, the variable track chassis comprising a fixed main chassis and at least one assembly (10, 10', 10") itself comprising: - a pair of fixed guide bars (12a, 12b) comprising a front guide bar and a rear guide bar on which the main chassis is fixed, each of said front and rear guide bars extending along a guide axis (17a, 17b) generally transverse, - a pair of chassis portions (13a, 13b) comprising a left chassis portion and a right chassis portion each slidably mounted on each of the front and rear guide bars along their respective guide axis (17a, 17b), - a first pair of wheel supports (14a, 14b) comprising a left wheel support on which a first left wheel is intended to be rotatably mounted, and a right wheel support on which a first right wheel is intended to be rotatably mounted, the or each assembly (10, 10', 10") further comprises: - a first pair of suspension arms (15a, 15b) comprising a left suspension arm and a right suspension arm pivotally mounted on one of the front and rear guide bars, around the guide axis (17a, 17b) of said front or rear guide bar, and sliding on said guide bar or rearward along the guide axis (17a, 17(b) of said front or rear guide bar, - the left and right wheel supports of the first pair being respectively pivotally mounted on the left suspension arm and on the right suspension arm of the first pair, around a pivot axis (20a, 20b) generally oriented in a vertical direction, perpendicular to the longitudinal and transverse directions, - a first pair of suspension systems (16a, 16b) comprising a left suspension system and a right suspension system, the left suspension system being mounted between the left suspension arm of the first pair and the left chassis portion or the main chassis, extending along a first left suspension axis, the right suspension system being mounted between the right suspension arm of the first pair and the right chassis portion or the main chassis, extending along a first right suspension axis. - a pair of fixed guide bars (12a, 12b) comprising a front guide bar and a rear guide bar on which the main chassis is fixed, each of said front and rear guide bars extending along a guide axis (17a, 17b) generally transverse, - a pair of chassis portions (13a, 13b) comprising a left chassis portion and a right chassis portion each slidably mounted on each of the front and rear guide bars along their respective guide axis (17a, 17b), - a first pair of wheel supports (14a, 14b) comprising a left wheel support on which a first left wheel is intended to be rotatably mounted, and a right wheel support on which a first right wheel is intended to be rotatably mounted, the or each assembly (10, 10', 10") further comprises: - a first pair of suspension arms (15a, 15b) comprising a left suspension arm and a right suspension arm pivotally mounted on one of the front and rear guide bars, around the guide axis (17a, 17b) of said front or rear guide bar, and sliding on said guide bar or rearward along the guide axis (17a, 17(b) of said front or rear guide bar, - the left and right wheel supports of the first pair being respectively pivotally mounted on the left suspension arm and on the right suspension arm of the first pair, around a pivot axis (20a, 20b) generally oriented in a vertical direction, perpendicular to the longitudinal and transverse directions, - a first pair of suspension systems (16a, 16b) comprising a left suspension system and a right suspension system, the left suspension system being mounted between the left suspension arm of the first pair and the left chassis portion or the main chassis, extending along a first left suspension axis, the right suspension system being mounted between the right suspension arm of the first pair and the right chassis portion or the main chassis, extending along a first right suspension axis. - a first pair of suspension arms (15a, 15b) comprising a left suspension arm and a right suspension arm pivotally mounted on one of the front and rear guide bars, around the guide axis (17a, 17b) of said front or rear guide bar, and sliding on said guide bar or rearward along the guide axis (17a, 17(b) of said front or rear guide bar, - the left and right wheel supports of the first pair being respectively pivotally mounted on the left suspension arm and on the right suspension arm of the first pair, around a pivot axis (20a, 20b) generally oriented in a vertical direction, perpendicular to the longitudinal and transverse directions, - a first pair of suspension systems (16a, 16b) comprising a left suspension system and a right suspension system, the left suspension system being mounted between the left suspension arm of the first pair and the left chassis portion or the main chassis, extending along a first left suspension axis, the right suspension system being mounted between the right suspension arm of the first pair and the right chassis portion or the main chassis, extending along a first right suspension axis.