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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11 thoughts on “Understanding Fly Line Tapers and Diagrams

  1. Thanks for the explanation. I’ve been doing this long enough to remember at one time of having a choice of only WF or DT.

    As I’ve got into switch and Spey rods in the last couple years (notice I said “got into” and not “got good at”), it seems to be even more confusing. Just the last three years it’s gotten crazy!

    Anything that helps me understand lines better is welcome. I can say that understanding and experimentation is worth it. All the specialization and choice can really improve your fishing expience, if your willing to put some time in.

    I’m no expert, but I know the Wulff Ambush line on my six weight has changed the way I fish streamers!

    There is no replacement for casting skill, but some of the new line designs can be valuable arrows is the quiver.

  2. As a fly fishing newbie, these types of posts are invaluable! I may not understand everything perfectly just yet but I can bookmark this and at least have the general idea in my head. There is so much to learn, I love it.

  3. The Triangle Taper (Royal Wulff Lines) has most of it’s weight in the back of the belly, close to the shooting line. Not in the front, as shown in the first picture. This looks more like a line for nymph fishing, or any other line where you need to turn over big flies or cast up against strong wind.

    • Agree w/ KRS. I fish triangle taper floating lines- the front taper is elongated running from tip to near the end of the head (increasing in diameter as it progresses) where it abruptly transitions back down to the running line (sharp rear taper). Otherwise a great article. Thanks for sharing.

  4. So what if 95% of my casts are 20 feet or less? Most of the time I don’t even have the entire head clear of the rod tip if I’m only throwing 15 feet of line, and in some cases (like the light presentation lines) I don’t even have the belly out, meaning I’m effectively casting 1-2 weights down from the lines rating. Do you recommend a weight forward or a DT line for work on small streams?

    • For small stream fishing you can simply over line your rod. Put a 5wt line on your 4wt and it will load with less line out. You might also think about your rod choice. Fiberglass rods are great on small streams because they usually have a parabolic action. The weight of the material itself loads the rod. These kinds of rods will make a loop with just the leader.

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  6. Great article! Too many folks just spool up whatever line is the most cost effective and the truth is their rod and therefore their angling could improve greatly with a more balanced line with the correct taper for their fishing application.

  7. Great article!!!
    Now maybe you could do one on shooting heads and running lines, which is what I use most of the time. Saves a lot of $$$ when the line wraps around a boulder on a float trip. I only lose the shooting head and not the $80 line. Plus I can cut off a bit of the running line if it becomes too frayed after years of service. I luckily still have two of Airflo’s long ago discontinued running lines which has proven more durable (and tangles less) than their “new and improved” ridge running line.

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