What’s on Your Reel? Fly Line and Backing Explained

Fly rods get all the glory, but when it comes to catching fish and delivering perfect casts, the line does much of the work. This is what you need to know when choosing fly fishing line to spool your reel.

fly fishing line selection

The only thing between you and that trout is your fly line and fly. Your line could present with a splash and spook the fish or it could be too heavy and drag your size 22 PMD down with it. You could run into your backing only to realize that it’s rotted, or your tippet could break off, the fish disappearing back into the water.

Fly line and backing are often an afterthought compared with rods and reels. But it’s just as important and technical as the other gear selections.

Fly Line Backing

Getting Into Your Backing

Backing is fairly simple, especially for freshwater trout applications. Most backing is braided nylon, stretch resistant, smooth, and rated in pound-test. For most trout fishing, a 20 lb. test is ideal.

How to pick fly line and backing

Typically when trout fishing, you do not run into your backing much. If you are fishing a two, three, or even four weight set up, you may not get much backing on your spool. When you are fishing a five weight for trout, the backing is mostly to fill your spool and be there in case you need it.

A five-weight reel generally takes between 80 to 120 yards of backing, depending on the line being used, reel arbor size, and design. When you get up to bigger fish or outfit sizes you might want to move up to 30 lb. backing.

Cortland Micron backing ($22 for 250 yards of 20 #) is a great choice that comes in a variety of colors and both 20 and 30 lb options.

When it comes to saltwater and higher weight setups, backing becomes even more critical. Big fish will run you into backing a lot. You don’t want a failure.

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If your reel is in a crunch for backing capacity, Hatch ($29 for 100 yards) makes a 68-pound test backing that is actually thinner than regular 20-pound backing. It’s also rot resistant. The only negative is the price. It’s three times the cost of the previously mentioned Cortland Micron backing.

Backing Attachment and Knots

Attach backing to the spool with a uni or arbor knot. Spin it on with a line winder. It is ideal to have backing mechanically spun on so you can make sure it is evenly laid and tightly spooled.

If you have to reel backing on by hand be sure to have a friend hold the backing spool so you can reel the backing on with a good amount of resistance. This will keep the backing from sinking into and cutting itself should the fish make a big run after you are already into your backing.

How to pick fly line and backing

Once your backing is placed, you most likely will want to tie a loop at the end backing where it will attach to your line. A double surgeon’s loop is good for this, as it provides a smooth transition from line to backing if it is running through your guides.

If you have the proper tools you can also tie a needle nail knot or make a blind splice loop for the smoothest connections. Most modern fly lines have welded loops on both ends, making connections to backing and leaders easy. If your line does not have a welded loop, you will have to tie a needle nail or nail knot to make the connection. 

How To Pick a Fly Line

How to Pick Fly Line

When shopping for a fly line, first, identify where you will be fishing. Will it be warm or cold water? Fresh or saltwater?

A warm water saltwater line is going to be stiffer in colder weather whereas a cold water line will be limp in a tropical climate. Matching your line to climate will ensure that your line transfers energy properly.

Next, is the line weight. What weight rod and reel are you using?

You usually match your line weight to your rod. Many graphite rods are designed with half-line-sized heavy lines in mind. The half-size heavy allows the line to load the rod quicker. In the end, it is more accurate and smoother to cast at closer distances (15-35 feet). Some lines are a full-size heavy, while others are true to size.

If you will fish more than one type of climate or want a sinking and floating line set up, consider buying an extra spool for your reel and switching that out when needed. Almost all reel manufacturers allow you to buy extra spools, and your local shop would be happy to rig it up for you. In general, an extra spool will run you roughly 50-percent of the cost of your reel.

Fly Line Tapers

The Scientific Angler’s MPX ($75) is great all around floating line. It is weight-forward (WF) and half-line size heavy, which is perfect for most modern graphite fly rods. If you are looking for a true to line sized line, check out the Scientific Anglers Trout line ($67).

fly fishing taper guide

If you are using a slow action graphite or glass rod, use a line that is true to line size. Buying a fiberglass specific or double-taper line is going to be ideal, check out the Scientific Angler’s Double Taper ($75) or the 406 Fly Lines Vintage Series Double Taper ($69).

fly fishing taper guide

The next consideration and most in-depth choice is line taper. In trout fishing, you will see two main tapers, weight-forward and double.

A good general taper for trout would be a weight-forward line. That means the taper is in the first 10 yards of the fly line. A weight-forward line is a good all-around line for its ability to cast and turn over a variety of tackle. Weight forward lines are also better for casting longer distances.

fly fishing taper guide

A double taper line is symmetrically tapered. It is best used for delicate dry fly fishing where presentation takes precedence over distance or power. Double tapers also mend better than weight forward lines and can be “flipped” after a season of use, making your line “like new” again.

Within weight-forward and double taper are many options for specific taper profiles. The MPX and Trout, through both weight-forward, have different tapers and will cast and turn over flies in different ways. The MPX’s taper is slightly more aggressive and loads better at close distances, as well as turn over larger, wind resistant flies. The Trout is well suited for dry fly fishing and more delicate presentations.

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Sinking Lines

For throwing streamers, you may want a sinking line or sinking tip line. Sinking lines can be as simple as a single density or as intricate as a triple density.

Part of the idea behind multi-density sinking lines and tips is to create a smooth cast. Single densities, like the Scientific Anglers Sonar Titan Full Sink (Intermediate) ($65 for a 6wt line), have one sink rate (1.25 inches per second). You could also check out Rio’s InTouch 15ft Sink Tip ($90) (3 or 6 inches per second available).

Triple density lines like Scientific Anglers Sonar Titan INT/SINK 3/ SINK 5 ($85 for 6#) have three sink rates thanks to different coatings of tungsten. Triple density lines seem to cast more like floating lines. They also handle easier than a heavy single density line.

If you have ever cast a heavy streamer set up, you would know that they are not always smooth. For a single density, check out the Rio InTouch 15ft Sink Tip ($90), for a double density try the Rio InTouch StreamerTip ($90).

Textured Fly Lines

Lines also come in a variety of textures. Traditionally, lines are smooth. But now, manufacturers are coming up with different textures. Textures reduce friction, increase casting distance, and increase the longevity of the line. The Scientific Anglers Amplitude series (starting at $103) utilizes a golfball-like dimpled texture to achieve this.

Wrapping It All Up: Line Maintenance

A well thought out line choice can be the difference between successful fishing and failure. The line weight and taper choice can compliment your rod and casting, bringing both to the next level.

As with any gear, the components need some maintenance. The backing can get mildew or cut into itself if not spooled properly. Keep an eye on it to make sure the integrity remains. A good rule of thumb is to replace the backing every other time you replace your line. Many reels are machined out so that air can dry your backing more quickly. This helps extend its life.

Lines can get nicked, dirty or knotted, so keep an eye on them as well. Rio ($13) and Scientific Anglers ($11) both make line dressing and cleaners to keep your line casting smoothly with less friction. If your line “squeaks” through the guides it is an indicator to dress the line with silicone gel.

Simply wash your line with soap and water. Scrub lightly to remove dirt and scum. Lastly, apply the silicone gel.

Follow these tips and keep your fly line and backing casting smoothly. Tight lines!

– Chloe Nostrant is a photographer and artist from Livingston, Montana. She is an employee at the famed George Anderson’s Yellowstone Angler and executive director of the non-profit Bridger Babes. She spends her free time chasing her next catch and creating work about the American West.