Abstract: A tensioning device for a traction drive comprises: a base body, a tensioning arm pivotably mounted about a pivot axis relative to the base body by a radial bearing, wherein one of the base body and tensioning arm has an annular carrier portion axially supported relative to the other of the tensioning arm and base body by a first axial bearing in a first direction and by a second axial bearing in a second direction, a first sealing element connected to said support portion for sealing said first axial bearing, a second sealing element connected to said support portion for sealing said second axial bearing, wherein the first and second axial bearings are made of a different material than the first and second sealing elements, spring means via which the tensioning arm is supported in the circumferential direction against the base body, and a tensioning roller which is rotatably mounted on the tensioning arm and serves to tension a traction means, wherein the first sealing element and the second sealing element