Where to buy OEM belts. I have a Troybilt TB 30 mower, model #13B726JD 023.

[slomo]

So I did the Napa belt crossover for the OEM belts for the OP and all 3 napa belts are slightly the wrong length and 2 are the wrong cut angle

Buy 10 belts of the same brand, width and length. None will be spot on in those critical dimensions. Stretch them out in your hands and see. Gates, Goodyear blah blah blah.