daniel_l,
If you asked what size belt I would have told you but you said that it was just replaced but you did not quote the size of the belt that was used.
If it was a mower shop that replaced it then they should have known the size in the first place but you did not quote who did the work so we can only guess who did.
As I said in my first post was is it the correct size belt.
The more information you can supply when asking questions the quicker the answers come.