v belts

[John B]

" can you bring a new belt for a 2QM F yanmar out with you today"

Phone call from mate out the back of Waiheke island hiding from the wind and gale warnings. " its 32 inch"

after calling the agents I get the 32 inch confirmed.. 'go to any auto parts place and grab a standard A type 32 inch belt.'
So the Auto parts guy says right .. A 32 ,here you go.

A32 and the fine print says 1/2 x 34 inch!!

34? cut a long story short I have to buy A 30 to get a 32 inch belt.
Why on earth would they code that way? just Bastards International infiltrating or is there a reason?

[Uncle Duke]

Full disclosure - I bring no intelligence here. But... are we talking inside diameter vs outside diameter?

[Hwyl]

Belts are usually measured by I.D. Are you going to "bracket" the sizes?

[Stiletto]

I wonder if it has anything to do with stretched length.

[ion barnes]

I can help,

V-belts are measured in a variety of ways depending on the usage/manufacturer. Industrial belts are A, B, or C sectioned while automotive were 1/2, 5/8, or 3/4 respectivly, and now there are metric in the same sizing. It all relates to the max width of the belt.

The length is a bit different and I cant remember the definative reasons why but, the length is measured at the mid-depth of the belt and therefore an A32 is a 1/2" belt with an OD measurment of about 34". Typically a 1/2" belt requires about 2" extra to accomadate the circumference of the pullies. As the pullies become quite large that measurment has to be enlarged but I am talking about belts inexcess of 100"

One common error when the label is obscured, is measuring a worn (stretched) belt and ordering the same without giving allowances for stretch. Always best to measure around the pullies with the adjustment fully collapsed.