Reading the sizeA size like 6 x 500 Li means a 6mm section belt with a 500mm inside length. Some sizes are given as the datum length (Ld) instead, which is a little longer, so check which one your belt shows.
Measuring a small beltIf the size has worn off, wrap a piece of string round the inside of the belt, mark it and measure the string. That gives you the inside length.
Check the sectionMeasure the top width and depth. A 6mm section belt is 6mm wide and 4mm deep. If yours is narrower, see our 5mm section; if it's wider, see 8mm or Z section at 10mm.
