The 100 amp alternator on my Westerbeke 44B is driven by dual v-belts, Gates 7405 size. I am trying to find a source for matched belts in this size. Manufacturing tolerances even within this size mean that belt tension is noticeably different between the two belts.
If they aren't sold as matched pairs (and Gates doesn't do so in this size from what I can glean) are there vendors that will somehow size a bunch of them and match them up to give best matched pairs?
"they" say, nowadays, that belts from the same manufacture run are as close as the old "matched sets"...
Have you thought about multigroove belts? Suposed to run cooler with less tnsion, grip better and last longer...just another boat buck or two for pulleys and spares cause you probably won't find em everywhere.
In a far away former life I sold such things. Look for an industrial supply house such as Bearings Inc. or Kaman Bearing or equivalent and give them the number. They will be able to access the info and get you availability or suitable upgrade, including sheaves. It should not be expensive.