Taper Design Fundamentals February 16, 2015 – Posted in: Basics



Short Version: The way a fly line is shaped determines how it will cast, present flies, and fish.

Longer, Super Scientific Version: How a fly line is shaped determines its performance through the air, with the line’s taper affecting how energy is transmitted and dissipated. Varying the lengths and diameters of the various parts of the fly line allows us to control this energy, resulting in accentuated performance characteristics for specific types of fly fishing.




Front Taper

Tip diameter and front taper length determine how a fly is delivered.

  • Longer front tapers mean more delicate presentations, as energy is dissipated over the length of the taper
  • Shorter front tapers mean powerful turnovers because more energy is transferred from the belly to the tip


The section with the greatest diameter, the belly also carries the majority of the weight and, therefore, energy.

  • Longer bellies increase casting distance and accuracy
  • Shorter bellies shoot better and cast faster, but sacrifice accuracy

Rear Taper

Rear taper length determines how smoothly the energy is transferred to the belly.

  • Longer rear tapers transmit energy smoothly to the belly for increased distance and control
  • Shorter rear tapers put the running line in the guides more quickly for faster casts


The level front end section of line, typically six inches long.

  • The tip allows you to change leaders without shortening the front taper or altering the way a line casts


The head—formed by the front taper, belly, and rear tape—dictates the effective casting and control range of a line.

  • Short heads cast quickly, but can sacrifice distance
  • Long heads offer more long-range control, but can require more false casting to clear the head from the rod

Running Line

This section of line helps make distance casting easier.

  • Running lines are lightweight, which permits the energy stored in the line’s head to pull the running line through the guides during casting
  • The smaller diameter of the running line also creates less friction in the guides, which promotes longer casts