well I ordered up the manual...and the parts diagrams... downloaded and had them printed off at the office store ouch. not really a lot of info in there but its a start.. lots of the original sales ads included in there as filler material. I measured what I thought the belt should be by closing the turnbuckle adjuster all the way in and then measuring around the 2 pulleys and then opening the turnbuckle most of the way and measuring again... i came up with 35.5 to 39 inches i believe... now in the replacement parts there are 2 sizes avail from logan a 38 and a 39 both seem to be at the upper end of the scale for length?? i would think anything would stretch over time?? and as the belt gets bigger and u adjust for such your throw distance decreases on the belt tensioner..