Re: Case belts
Here are the facts.
The pulleys for v belts are generally sized as for 1/2" belts and can take 1/2" and 3/8" belts. The next size up in pulleys is 5/8". These take 5/8" and 1/2" belts. Case put out a Belt Equivalency Chart stating that all belts are 1/2" belts. They did this even though the deck drive pulleys are for 5/8" belts and the deck pulleys on many deck versions are for 1/2" belts max.
But, the belts that Case sells are actually 9/16". They are not at all common in size out in the wild of belts and vendors. The 1/2" belt, when used on the drive pulleys, starts at the bottom range of the pulley. It does not take long for the 1/2" belt to reach the bottom of the pulley. Once the drive belt reaches the bottom of the pulley, it no longer performs well.
When I get a used Case genuine belt, I measure its width. Once it is near 1/2" I consider it a spare and order a replacement belt. As you know, not all belts are made the same. The genuine Case belts are constructed in a way that will give many years of service. I have been looking for years for a belt made as well as the Genuine belt. I have not been able to.
The reason I do not use a 5/8" belt, even though the pulleys are clearly made for 5/8" belts, is the belt twist in the case system. First it is a lot of belt to twist in the way that they are twisted. Second, they are riding very high in the pulley AND twisted. But, a lot of people use the 5/8" belt and seem to be happy.