Mtb tyre bicycle tyre sizes 26 x 2125 26 x 190 26 x 210 26 x 195 26 x 220 26 x 200 26 x 225 inches sizes etrto 54 559 50 559 57 559 diameter inches 26 inch applications city cross country type clincher weight 730 g series continental town country max tire pressure 5 bar