Plus size tyres are great and with the XM521 they find their ideally matched counterpart. It offers all the support needed by the most aggressive of riders, yet it keeps the weight really low. This is important since big tyres tempt you to goof around on the trails and any rider would rather spend their energy jumping off obstacles than wasting it dragging along extra weight. That’s the XM521: a rim ready to put smiles on riders’ faces.