Do You Need Fishing Line Backing?

Fly fishing requires many different elements of not only your rig but the entire preparation process to come together in harmony. The type of line you choose, the backing, the knots you use to secure them, the reel, and so much more all need to be just right to give you the best chance of catching that fish of a lifetime. You may be unsure of whether you should include backing in your rig, so use this guide to decide.

Do you need fishing line backing? Fishing line backing is not a required part of your setup when fly fishing, but it can be a tremendous help to the strength and durability of your rig, and it gives you a greater chance of catching your fish.

There are few different aspects that play into just how much fly line backing can help you. Depending on the type of backing you purchase, Dacron vs. gel-spun, for example, the length, and weight capacity, your fly line backing can help you in freshwater habitats or saltwater fishing and may be suited to work best with certain species over others.

What is Fishing Line Backing?

Since so many people recommend its use, what exactly is fishing line backing? The fishing line backing is a thin section of the fishing line that is attached directly to the arbor of the fly reel. The backing helps to offer security to your fishing experience by providing a stronger portion of line to the otherwise very flexible fishing line. 

As implied by the use of a fly reel, the backing line is mostly beneficial to the sport of fly fishing, especially when fishing for game such as tarpon and steelhead – fish that put up a pretty good fight after being caught. In fly fishing, the line goes through quite a bit of abuse and is flung back and forth almost constantly, so the backing provides additional support for your rig, ensuring that the line doesn’t break the second you get your fish!

There are different types of backing depending on the type of fly fishing you’ll be doing and the species you’re aiming for. Backing is available primarily in the form of Dacron or gel-spun varieties – Dacron being made of a type of polyester material (polyethylene terephthalate, or PETE) used in most plastics, and gel-spun being comprised of high-modulus polyethylene (HMPE), a polymer used in the manufacture of body armor, among other things.

Most fly fishers have come to prefer the HMPE backing, as it is extremely strong yet with a dramatically smaller diameter. This variety has a 75% greater capacity in weight/resistance than Dacron, and with the smaller diameter, it has greater flexibility and maneuverability as well!

The Function of the Fly Line Backing

The primary function of the backing is to provide additional support to your rig when you get a fish that tries to run several hundred yards. When anglers talk about “running into the backing,” what they are referring to is when the fly line is extended to its maximum by the fish. Having an additional few hundred yards to support your fly line is greater insurance to catching your fish. 

Secondly, the backing works to fill up the arbor of the reel – why is this important? Without the backing, the arbor isn’t exactly “full,” and so whenever you are reeling in a fish, with every crank, you are not effectively pulling in much line. On the other hand, when you have backing, you have increased the size of the arbor, allowing for more line to be brought in with every crank of the reel.

This said, having backing on your fly fishing rig is not a formal requirement, but it is a tremendous help. Without it, you will be doing a lot more work for less certainty of catching your fish.

Types of Fishing Line Backing

The type of backing you choose for your rig can make or break your fishing trip, so you need to be confident that the type of backing you choose is right for your purposes. Essentially, your backing should serve as the “buffer” between the line and the reel. Many fly lines that you will come across will be about 100 feet in length (give or take), and the backing can add another 100-200 yards onto your rig.

In addition to adding some security due to its strength and weight, the backing supplies “insurance” with its additional length in the event that a fish is strong enough to take out an angler’s entire fly line. The backing also helps to fill the reel by allowing individual turns of your reel to pick up more fly line than it would otherwise. Ultimately, this means you will get more time fishing instead of struggling to bring in fish.

Now, again, depending on the type of fishing you’ll be doing and the species of fish you’re aiming for, you need to pay special attention to the types of backing your rig may need. Here are the main types of backing below and what they are recommended for:

Type of BackingDescriptionSpecies/Uses
DacronKnown widely for its high tensile strength, low stretching, and durabilityTrout fishingSmall water bodies
MicronEssentially the same as Dacron, however, Micron is a braided backing made of Dacron fibers with a special coating and greater strength.Trout fishing
Polyethylene (PE)Still quite durable, PE backing is UV resistant and narrower in diameter than Dacron. (PE is the most commonly-used plastic around the world, it’s in grocery bags, plastic bottles, and similar daily items.)Saltwater fishing
Gel-spun (Spectra)Braided from PE, this type of backing offers increased line strength while having more on the reel since the diameter is smaller than PE. (Note that gel-spun backing is not hollow and therefore cannot be spliced in the way that Dacron can be.)Saltwater fishing (especially Bluewater)

How to Know if You Need Fly Line Backing

To determine your need for a fly line backing, you need to take note of the type of fish you’re aiming to catch and where you’ll be fishing. If you are going to be fishing for smaller or average-sized fish that don’t put up too much of a fight, then the length of your fly line should do. However, if you’re fishing for anything bigger than a little brook trout, you’ll want to arm yourself with some backing. 

It’s especially important to note where you will be fishing and the environmental conditions associated with your fishing site. This is because even natural elements such as the current of the river will play a part in your need for backing. It is quite easy for a fish to run out a typical fly line, and a strong current will only help it to do so.

Additionally, note if you are going to be fishing from a boat or other vessel, or from the shore. Depending on the position from which you will be fishing, there may be environmental elements that prevent you from closing in on your fish the way you might want (rocks or vegetation in the way of the boat, for example).

Most importantly, keep in mind that it cannot hurt you to have fly line backing! If you feel that it would certainly help you to have those additional tens up to two hundred yards, then, by all means, use it! Fly line backing only serves to add security to your fishing experience and will not hurt your performance if you happen to only use the length of the fly line.

With or Without Braiding?

According to Bryce Poyer, owner of White Water Outfitters, backing with braiding (as opposed to monofilament) is far superior to backing without it, as the braiding gives you greater capacity, makes your rig stronger, and adds versatility to your setup. The better performance of a braided backing will also inevitably save you money over time because of its longevity, despite its higher price upfront.

What you should keep at the forefront of your mind, though, is that braided backing can have a very narrow diameter. Depending on your reel, this can be quite destructive to your catch, as the backing can begin to slip on your reel and impede your ability to pull in your fish.

However, it is recommended that for live bait fishing, you avoid using braided backing, especially when you’re drifting. This is because it is much easier to get tangled with braided backing than monofilament backing – and braided backing is a bit more of a hassle to replace, as it is more expensive. Still, you can combat this with the type of reel you use and if you combine your braided backing with monofilament. 

Regarding the reel, if you are set on using braided backing on its own, there are ways to ensure that your line doesn’t slip. Some reels come with the spool “rubberized,” meaning that the spool is not just smooth metal, but has a rubber middle, keeping the backing in place so that you don’t have to worry about it slipping while you’re reeling in your fish.

Advantages and Disadvantages of Braided Backing
More durableCould slip on your reel, depending on type of spool
VersatileMore expensive
Greater capacity

What Weight Should I Get for My Fly Line Backing?

The weight of your fly line backing should correlate with the size and species of fish you’re after and where you’ll be fishing (freshwater lake vs. open ocean, for example). 

Some example recommendations include: 

  • 12-lb backing for small trout and panfish
  • 30-lb backing for salmon
  • 30-lb backing for tarpon and large marine fish

Generally, 20-lb backing is a great choice for those who do inshore fishing in saltwater, while 30lb backing is better for when you’re farther out on the open ocean, where the fish will inevitably be larger. On average, most inshore fish will run about 75-100 yards before they begin exclusively resisting you, so it is best that, in addition to an appropriate weight, you have at least 175 yards of backing.

(For both inshore saltwater fishing and freshwater fishing, you can generally get away with 20-lb and 30-lb backing no matter what you’re fishing.) 

Bluewater fishing will require more at a minimum of about 300 yards of either Dacron or gel-spun backing, ideally. In addition to the fish’s run, you must also realize that with bluewater fishing, the fish have the opportunity (and ability) to swim to greater depths, so this will add to your need for the reach of your backing!

Diameter of the Fly Line Backing

The diameter of your fly line backing correlates with the weight capacity but does not necessarily represent the breaking strength of the backing, but the durability. What this means is that the diameter of the backing partially dictates its ability to withstand abuse from the elements: friction from rocks in freshwater environments or coral in saltwater habitats (otherwise known as the “abrasion resistance”).

You will also need to consider the diameter of your backing, depending on the type and size of reel you have. This is because the diameter of the backing will determine just how much it is able to fill up the arbor.

What Length of Fly Line Backing Do I Need?

Again, when deciding to add backing to your rig, take into consideration where and what you will be fishing, as that will not only determine what weight you need for your backing but the length of your backing as well. Certain species of fish will run for shorter distances than others. Most of the time you’re in freshwater, you will not have to worry about running into your backing, and so will need less. 

When fishing in freshwater, the maximum you’d ever really need is 250 yards – the biggest fish being something like bonefish or carp. In freshwater, you should be thinking mostly about the behavior of the fish and the distance it’s likely to run before being relatively still and fighting you instead. This may seem like an obvious note, but it is because there are just a few nuances when considering the length for marine fishing.

Of course, in marine fishing, you’re going to have to consider the fish’s behavior as well, however, where on the ocean you are fishing is going to have a more dramatic effect on the type and length of backing that would be most appropriate. 

As was briefly mentioned above, bluewater fishing opens up the opportunity for a fish to not only run away from you but also to swim downward. This may not be a typical – or even expected – behavior for most fish, but you do need to take into account that it is a possibility. You can get away with a shorter backing when doing inshore saltwater fishing. 

How to Attach the Fly Line Backing to Your Fishing Rod and Reel

Now, when you’ve finally decided that you do, indeed, need the fly line backing, it is time to attach the backing to your reel and rod. You need to pay special attention when setting up your rig so as not to damage your rod, backing, or reel, or impede your fishing experience later on. 

(Note: Although you are completely free to set up your rig on your own, it may be better to let the shop do it for you, so nothing is overlooked! A reputable outfitter will have no problem doing this for you!)

Setting Up Your Fly Fishing Reel:

First thing’s first: your reel will need to be adapted to right-hand or left-hand retrieval. If you are having the shop set up your rig for you, make sure to let them know ahead of time which configuration to use. This is because, as you know, those who are using a right-hand retrieval will be reeling with their left hand, and vice versa. Instructions will come with your reel to guide you in this part.

Attach the Backing

Using the arbor knot (otherwise known as a “uni knot”): Start by making a loop around the arbor with the backing. With the two pieces extended away from the arbor, fold one free end over both of those two pieces back toward the arbor. Now you have a loop in your hand. Now it’s easy: simply make an overhand knot five times and pull on the extended pieces to cinch it down on the reel. 

You may need a buddy for this portion: Now that you have the backing cinched down, you need to reel it all onto the arbor. You can find a way to extend the backing yourself or have a friend hold the backing away from you as you reel it in.

Attach the Fly Line

Tie on the fly line: First, pay extra attention to the labeling of your fly line before attaching it to your backing and reel! So often, anglers have accidentally put their lines on backward simply because they were moving too fast and didn’t stop to look at which end is which.

When you remove your fly line from the packaging, the end that is meant to be attached to the reel is on the outside, while the “business end” will be on the inside, on the spool. If you get this mixed up, it will severely impact your ability to cast. 

It is best to use a tool like the Tie-Fast Knot Tyer (click link to see on Amazon) for this step to make this much easier and quicker. Align the backing with the middle of the tool and extend it through the fork at the end. Simply loop the line around the tip of the tool about six times, then insert the free end of the backing into those loops and pull it out through the fork of the tool. Now, insert the fly line into the loops in the opposite direction you used to pull the backing through the loops. Pull the end of the backing off of the fork, bringing the loops with it to then tighten on both the backing and the fly line, and now you’re ready to fly fish!

Items recommended in this article

Recent Posts