I was looking for information about the size of these belts. One older
post said they were 43 inches, which is the internal circumference. The pulleys on my flail mower have an internal circumference of 41 inches measured from the base of the grooves. For this size a 42 inch internal circumference belt is needed. I replaced mine with Kevlar belts. It was quite easy to wind them on by placing the belt in the top pulley's inner groove and winding it on over the smaller bottom pulley into its outer groove. It was quite easy to then make it jump over the middle separator to the inner groove. Took about five minutes to fit both.
