How to determine belt length?

For those of you who build custom stuff and need a different length belt than stock, how do you determine the correct length? On my murray I've swapped pulleys, both 5" and I changed the clutch setup to a design that needs a longer belt. The stock 96" belt is way too short, it's tight before I even get it on the motor pulley, tight just against the motor shaft. I put all the pulleys on and released the clutch and used rope to measure and came up with 98". This is obviously too short since the small rope fits into the V notched pulleys tighter than a belt does. So I'm kinda stuck, especially since I plan to order the belt online, much cheaper. So is there a foolproof way to get this measurement?

i would say go with the around a 97. its alright if its a tiny bit to short because your clutch pulley gives you some room to work with. if you had a old longer belt you could cut that and wrap it around your pulleys then subtract what overlaps

a good place for cheap belts is http://www.surpluscenter.com/sort.asp?catname=powerTrans&keyword=PBAA just keep scrolling for bigger sizes. page 5 will have what you need

you are going to want to do a bit of maths!! but i use a piece on think ish rope, I also once got a 150 inch belt and cut is in half, I can use it as guide.

I forgot I posted this. I ended up cutting a belt to measure with. Ended up needing a 101".

Jamus wrote:

I forgot I posted this. I ended up cutting a belt to measure with. Ended up needing a 101".

101" ?? How long is your machine??? Man the longest belt I think I've ever needed is 88" lol

Stock is 96" I think. Then I swapped the double pulley clutch from a hydro murray onto it which requires more length.

Thats nothing- the belt on my 42" dynamark deck is about 107" long- thing was longer then the belt mesuring stick at TSC, one of the longest belts they carried.