You can get my with aftermarket on snow blowers and some really old mowers typically older than 1997 and sometimes on Fwd craftsman BUT I will NEVER install a non MTD rider belt on an MTD mower on the double belt drive (double sheave pulley) system OR the deck blade belt.I get belts from ebay from the seller D&D Power Drive, Have all the sizes I have ever ordered.
They are in Iowa, belts run a little short. I am in Wisconsin, get belt in about 4 days.