Abstract: Elastic or flexible protective bellows of a homokinetic transmission joint for a motor vehicle wheel, connected in a sealed manner to a bowl element 2 of the joint, comprising, when mounted on the joint, an active part constituted by two coaxial spherical segments 3, 4, one of which is outside the other, interconnected by a curved trough 5 and defining with the latter a U shape. The active part 3, 4 can extend by a lengthening of the segments, on one side, and a shortening, on the opposite side, when the joint pivots through a given angle. This joint has, in particular, the advantage of completely eliminating wear by abrasion between the inner surfaces of the joint, the active segments 3, 4 being indeed always separated by lubricant. Further, the many folds of conventional bellows are eliminated, which considerably simplifies the manufacture of the bellows.