What is the proper way to figure the correct size for a fan belt or PS pump belt?
Is it best to measure the around the OD of the pulleys? Or the inside diameters, like with a string?
Thanks
Jim

Likely not considered to be the proper way but I just take an old longer belt that’s cut to length and get the parts store to match up the size.  The inner belt dimension tends to come closer to getting the length that’s required.

Lorena, Texas (South of Waco)

Thanks, Ted