A forestry vehicle comprising: - a chassis; - first and second pivot arms (3, 4) arranged opposite each other on opposite sides of the chassis, each of which having a first end (3a, 4a) and an opposite second end (3b, 4b), wherein each pivot arm at its first end (3a, 4a) is pivotally mounted to the chassis so as to be pivotable in relation to the chassis in an essentially vertical plane about a pivot axis (A1, A2); - a first drive wheel, which is carried by the first pivot arm and rotatably mounted to the first pivot arm at the second end thereof, wherein the first drive wheel has a centre axis, whereby the first drive wheel and its centre axis are pivotable with respect to the chassis; and - a second drive wheel, which is carried by the second pivot arm and rotatably mounted to the second pivot arm at the second end thereof, wherein the second drive wheel has a centre axis, whereby the second drive wheel and its centre axis are pivotable with respect to the chassis, wherein - the vehicle comprises: • a rotatable first idler wheel carried by the first pivot arm and a rotatable second idler wheel carried by the second pivot arm, wherein the first and second idler wheels (9, 10) have an external diameter (d) that is equal to or smaller than half the external diameter of the first and second drive wheels (5, 6), • a first track belt arranged in an endless loop around the first drive wheel and the first idler wheel, and • a second track belt arranged in an endless loop around the second drive wheel and the second idler wheel; - the first idler wheel is located on that side of the first drive wheel that faces the pivot axis of the first pivot arm; and - the second idler wheel is located on that side of the second drive wheel that faces the pivot axis of the second pivot arm. - a chassis; - first and second pivot arms (3, 4) arranged opposite each other on opposite sides of the chassis, each of which having a first end (3a, 4a) and an opposite second end (3b, 4b), wherein each pivot arm at its first end (3a, 4a) is pivotally mounted to the chassis so as to be pivotable in relation to the chassis in an essentially vertical plane about a pivot axis (A1, A2); - a first drive wheel, which is carried by the first pivot arm and rotatably mounted to the first pivot arm at the second end thereof, wherein the first drive wheel has a centre axis, whereby the first drive wheel and its centre axis are pivotable with respect to the chassis; and - a second drive wheel, which is carried by the second pivot arm and rotatably mounted to the second pivot arm at the second end thereof, wherein the second drive wheel has a centre axis, whereby the second drive wheel and its centre axis are pivotable with respect to the chassis, wherein - the vehicle comprises: • a rotatable first idler wheel carried by the first pivot arm and a rotatable second idler wheel carried by the second pivot arm, wherein the first and second idler wheels (9, 10) have an external diameter (d) that is equal to or smaller than half the external diameter of the first and second drive wheels (5, 6), • a first track belt arranged in an endless loop around the first drive wheel and the first idler wheel, and • a second track belt arranged in an endless loop around the second drive wheel and the second idler wheel; • a rotatable first idler wheel carried by the first pivot arm and a rotatable second idler wheel carried by the second pivot arm, wherein the first and second idler wheels (9, 10) have an external diameter (d) that is equal to or smaller than half the external diameter of the first and second drive wheels (5, 6), • a first track belt arranged in an endless loop around the first drive wheel and the first idler wheel, and • a second track belt arranged in an endless loop around the second drive wheel and the second idler wheel; - the first idler wheel is located on that side of the first drive wheel that faces the pivot axis of the first pivot arm; and - the second idler wheel is located on that side of the second drive wheel that faces the pivot axis of the second pivot arm.