Understanding Fly Line Tapers and Diagrams

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Photo by Louis Cahill

Photo by Louis Cahill

By Louis Cahill

Buying a fly line doesn’t have to be a leap of faith.

For many anglers, fly lines and their characteristics are a huge mystery. They know that different fly lines cast differently and that some suit their needs or casting styles better than others but they have no idea why. What’s worse, when it’s time to buy a new line they aren’t able to make an informed choice. They just go to the fly shop and ask for the best line. Thank God for knowledgable fly shop guys, but do you really want to rely on someone else’s guess at what you will like?

If this sounds like you, I have good news. There is an easy way to get a sense of how a fly line will cast before you ever take it out of the package, and with a little experience you can quickly choose the line that’s right for the way you fish.

Fly lines have become really complicated in the last five years or so. Specialty lines have multiplied like rabbits and line companies have created lines to match every species, water condition and casting style. If you’re confused, you’re not alone. Fortunately, almost every manufacturer publishes line diagrams which show you, in detail, the taper of each line. If you know how to read the diagram, you’ll know how the line will cast.


flylinesThere are three basic types of line tapers. Weight forward, double taper and triangle taper. Looking at the diagram, it’s pretty clear how they get their names. The double taper line is a very traditional style of line which has a long level belly and a symmetrical taper on each end. Weight forward lines shift the weight to the front of the line and were developed to match modern fast action carbon fiber rods. Triangle tapers are a kind of hybrid of the two.

Think of the diagram as a picture of the fly line in profile with the thickness of the line exaggerated. The thickness of the line indicates two things. Where the weight is and the relative stiffness of the line. Where the line is thicker, it will be heavier. Different line materials have different stiffness, but within a given fly line, the line will be stiffer where it is thicker. Knowing where the weight is in the line will tell you how it loads the rod and the stiffness, as well as the weight, will tell you how it presents the fly.

Anatomy of a Fly Line

taperTo understand the information the diagram gives you, first you have to understand the different parts of the fly line and how they affect the line’s performance. Most modern fly lines have five parts. From front to back they are the tip, front taper, belly, rear taper and running line. Each one performs a specific function and its weight and length determine how the line casts.

The Tip

The tip is the final word in fly presentation. The longer and lighter the tip, the more delicate the presentation. A long light tip will work to your advantage when making soft dry fly presentations on a spring creek. A shorter, more aggressive tip with more weight will have the power to turn over heavy streamers and nymph rigs.

The Front Taper

The front taper dissipates the energy of the line during the presentation. Even more than the tip, the design of the front taper dictates how much energy is delivered to the leader and what kind of presentations the line will naturally make. A short front taper is called “aggressive” and delivers a lot of power to the leader. It’s great for turning over heavy flies and straightening leaders out in the wind but will tend to slap the fly down on the water. A longer front taper is called “technical” and will make more delicate presentations, but may require very good casting in high wind or with heavy flies.

The Belly

The belly of the line is designed to load the fly rod. It carries the bulk of the fly line’s weight and is designed to match specific rod weights. It also determines how heavy a fly the line will carry. A longer belly will load the rod more gradually and allow the caster to carry more line in the air during false casting. It will also roll cast and Spey cast more easily. A short, fat belly will load the rod quickly for short casts and shoot line aggressively.

The Rear Taper

The rear taper is the transition from the belly to the running line. It is the last part of the line which is controllable during casting. A long rear taper offers the caster some control over the line when carrying a lot of line during false casting. A short rear taper offers the caster a quick transition to the running line, allowing them to shoot line more easily.

The Head and Shooting Line

It’s worth mentioning that the front part of the line, (the tip, front taper, belly and rear taper) are often collectively referred to as the “head.” The running line may also be called “shooting line.” These terms come from Spey line designs but are often used in reference to single hand lines.

Some Specific Examples

The RIO InTouch LT

InTouch-Trout-LT-WFThe LT is a delicate presentation trout line. You can see from the diagram that it has a long 8 foot tip. A 20 foot front taper and a short belly. Clearly a very technical line for light presentations.

The RIO Gold

RIOGoldA great all around trout line, the Gold has a much more aggressive taper. No tip to speak of and short 5 1/2 foot front taper. A 22 1/2 foot belly is backed up by a long rear taper. Notice that the head length is the same as the LT but the weight is shifted forward, delivering more power to the leader, loading the rod faster and making it easier to shoot line.

The Scientific Anglers Titan

Sharkwave-Saltwater-TitanThe Titan sports a radical head designed to turn over huge flies with ease. The compact belly and rear taper mean it’s a line shooting machine.

The Airflo 40+ Sniper

Forty_Plus_Sniper_5The Sniper is a true shooting head design. The short heavy belly and front taper coupled with a virtually nonexistent rear taper will shoot line like a cannon. There’s a reason this line has an extra 20 feet of running line.

The Airflo Tropical Punch

chard-tropical-taperMy personal favorite saltwater line, the Tropical Punch combines an aggressive belly and short front taper with an extra long rear taper. This line will punch into the wind but still gives you the line control you need to carry line on a long, precise presentation.


Having the ability to match a special purpose fly line to the type of fishing you do can really improve your performance as an angler. Hopefully this will help you understand how fly lines work and help you make more informed choices when purchasing your next fly line. It may even help you understand the lines you already have. 

Louis Cahill
Gink & Gasoline
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7 thoughts on “Understanding Fly Line Tapers and Diagrams

  1. I’ve been fly fishing for 53 years and using the internet for 34 years so I still have to learn a lot about fly fishing. However I’ve always known the specs of the fly line including breaking strain for all of my fly lines. When any new lines come out I always look at the specks to ascertain whether they could be a choice for me in the future. If I can’t find the specs I write to the manufacturer and ask them for the specs and when ever I have done that the service has been good. Am I the exception? I would have thought everyone would want to know the specs before they parted with there hard earned cash.

  2. If I may be so bold to point out that the diagram for a ‘triangle taper’ is wrong boys. the head should be a wedge shape with the thickest part closest to the running line.

    • That’s the first thing I noticed too. The triangle taper should be thick at the back tapering down towards the tip… The taper in that picture would be more of a “wind” taper imo.

  3. I agree with Tom Bell and Dan.
    Triangle taper is essentally a very elongated front taper.
    Its super for delicate presentations, roll casts and single hand spey.

    Otherwise, my congratulations on an excellent article!

  4. Pingback: Tippets: Burke’s Holiday Gift Guide, Understanding Line Tapers - Pesca y Bits

  5. The Triangle Taper does not have a “belly”. It is a continuous taper for the length of the head, so that heavier line is always turning over lighter line in the cast. It has a relatively short back taper between the head and the running line. In diagram it is an elongated triangle.

  6. Hi, from Japan !

    I tried flyfishing when I was 10 for the first time. This year, I’m going to try again !!
    This article is so perfect, and it will help me.Thank you !!

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