Fly Line Backing – Everything you Need to Know

This post was last updated on December 3rd, 2022 at 07:42 pm

What is Fly Line Backing?

Fly reel backing is normally made of dacron or braided polyester, it is the first layer of line you will put on your fly reel. It is generally sold in 50-100 yard spools. Backing is a braided line made up of many small strands. It comes in many different tensile strengths. The typical size for the average trout reel is 20# test. Most fly fishing reels will be able to accept either 50 or 100 yards of fly line backing. If you don’t already have backing, you can buy the troutster brand here at Amazon.

Troutster fly line backing

Is Fly Line Backing Necessary?

You could live without backing, but for the reasons below I would recommend you use it.

Fly Reel Backing – Filling Up the Reel

Various colors and sizes of backing line
Shop now for backing on

You need fly line backing to fill up the extra space on the reel for the same reason you would use a large arbor reel. To allow you to take up line faster. With only fly line and no backing on your reel, you will not be able to reel in as fast as you would with backing. If you were to wrap line around a thread spool, the small diameter would cause you to have to wrap it many times and not use up much line; however wrapping line around a larger spool would take up line at a much faster rate with the same amount of revolutions.

You also need it in case you hook a large fish, because the fish needs to be allowed to run. With no fly line backing on your reel, the maximum the fish will be able to run is the length of your fly line. Fly line is very expensive. If the fish were to pull all of your line out you would have about 60$ worth of line at risk on the one knot that connects your line to your reel.

I can’t even count the amount of times that I have seen people get all of the fly line pulled from their reel from a fish. Usually this happens in larger rivers with a lot of current. Also it tends to happen while the boat the fisherman is sitting inside is moving downstream at a fast rate, while the fish is either moving upstream, caught in a log jam, or just huge and not budging. The fish will wrap the line around a log or rock and continue up or down stream. Line just keeps peeling out of the reel until the boat can find a place to stop. Inevitably the fish will be gone after breaking the leader. This leaves the fisherman scratching his head, usually saying what did I do wrong.

How to Tie Fly Line Backing to Your Reel and Fly Fishing Line

Tying the Backing line to Your Reel

How to Tie the Arbor Knot, This connects your backing to a fly reel.
The arbor knot is used to attach your fly line backing to our fly fishing reel. It is tied by making a single overhand knot with your tag end around the main line and one other overhand knot to prevent the line from pulling through. It is basically 2 overhand granny knots and then pulling it all tight slowly.

The fly line backing is tied to your reel using an arbor knot. This is a very simple knot to learn how to tie. I have included an illustration to help you out.

How to Tie Fly Line Backing to Fly Line

The standard knot used to attach backing to flyline is called the Albright knot. It is a fairly simple knot and can be tied in less than 30 seconds. This knot is critical and if not tied properly could not only cost you the fish of a lifetime, it could cost you your whole expensive spool of fly line in the event of a hard running fish. Get this knot right and test it with several hard pulls to determine if it has the appropriate strength. You can learn the albright knot here to attach your fly line backing to your flyline or by using the video provided below.

Summary – Fly Line Backing

In this article, we looked at the importance of fly line backing on a fishing reel. Fly line is very expensive and without backing, you run of the risk of losing your entire spool. Fly line backing is helpful in multiple ways and should definitely be something you consider using.

To learn a little bit more about backing and all of the other parts of the fly fishing line, check out this article on fly fishing line setup or tippets and leaders.

Fly Line Backing FAQ

How much backing on a fly reel?

Most fly fishing reels will be able to accept either 50 or 100 yards of fly line backing.

What size backing for fly line?

The most commonly used backing is braided nylon in weights of 20lb or 30lb test. For light duty saltwater and most freshwater fly fishing, 20 lb is recommended. 30lb is generally used for larger game fish and saltwater fishing.