Belt Sizing
How are belts measured?
The numerical portion of belt part numbers represent the total circumference in inches (as if the the belt was cut and laid out flat on a ruler, without being stretched beyond its relaxed length.)
Broken belt
If your belt is broken at one spot, it is very easy to measure - just lay it alongside a ruler and measure its length in inches. Deduct 5%-10% to compensate for stretching of the old belt. Keep reading below:
Complete unbroken belt, but stretched
If the belt is complete (unbroken), you measure the length of the complete belt along a ruler (in inches) and then double that measurement (deduct 5%-10% to compensate for stretching). Keep reading below:
Missing belt, or old belt turned to goo
If the belt has turned to goo and is unmeasurable, measure the belt path in inches with a string pulled very taut (wrap the string around the pulleys just as the belt would go) . Cut through the string at the point where it overlaps, discard the ends and then measure the length of the string (in inches) that was wrapped around the pulleys. This is the actual length of the belt path. Deduct 5% to 10% to compensate for stretching. Order a belt with the resulting length (in inches). VCRs use the SBL size belt in most cases, and if it is a flat belt, the FBM size.