The tip diameter of an 8-weight floating line is about .040 inch, requiring a larger .026-inch-diameter leader butt to get the leader to turn a large fly over properly in casting.

What is a Leader? Fly fishing leaders are thin sections of monofilament or fluorocarbon designed to connect your fly line to your fly.

Tight Line Nymphing Set Up Tight-line nymphing is all about maintaining contact with your flies underwater – it’s accomplished by keeping your fly line off the water and holding the leader ...

Most light trout leaders conform to that standard. Problems may occur when you start switching line, leader, or fly sizes.