O.K.,As you know I had too much braceheight with the new SBD string that I bought for my old Bob Lee Bow.My old shot in b50 string was57+5/8ths unstrung,new string was 58"I would put the new string on and get a inch more braceheight.Didnt make sense,I thought.So,after much monkey business,I took down my old Martin Hatfield wit a much used,but great ff string made for me by a friend.Off the bow it measured 57.5"I,perfect braceheight on this bow is 8.75".So I  put the SBD string on it,strung it up and got 8.75 brace height.So ,then I took my old FF string from my Martin ,put it on the Bob Lee,strung it up and boom 8.5" brace height on the Thunderbolt!Prarie drifter was 100% right.The B50 string is an inch longer when strung ,than when relaxed.And I figured that it was pretty well shot in.Moral of the story is when replacing your b50 with an SBD add 3/4s to a full inch or measure the b50 stirg,strung on the bow.Thanks for the help guys,I really appreciate it.

Glad I could help!