If there is one component of a fly-fishing rig that is given little more than passing thought, it is the fly line backing. Fly fishers obsess over reels and rods; analyze the performance of fly lines and leaders, but backing – never. Buy a new reel, and the backing is often thrown in for free.

It’s helpful to remember what backing does. Fly-line backing has at least four functions. The first is that it raises the level of the fly line to near the top of the spool. By some accounts, that improves casting. And it also improves the retrieve, allowing more line to be taken up for each rotation of the reel (recall your high-school geometry).

The second purpose is that it adds weight to the fly reel, helping to improve the balance (or sense of balance) that a fly fisher feels when holding and casting the rod. Properly balanced, the rod and reel will feel neither tip-heavy nor reel-heavy.

A somewhat arcane purpose is that it actually helps with heat buildup. As that reel is spinning it’s generating heat through the friction of the drag or the line being taken in. The friction can be enough to damage the coating of a fly line.

Finally, the backing provides additional line for fighting a larger fish. Most fly lines are approximately 100 feet in length. A big fish can easily strip that amount of line when it runs. Without backing, the tippet will be quickly broken as the drag setting of the reel becomes irrelevant and all the fish’s fighting will be absorbed by the tippet.

Given all that it does, one would assume that people would give careful consideration to the backing on their reels.

Unfortunately, that is not true. Trout and bass fisherman often use whatever 20-pound test Dacron backing that is put on their reel at time of purchase Larger species mean use of 30 pound (or more) backing. And with larger species, more capacity is required, resulting in gel-spun backing being substituted for Dacron.

And yet gel-spun has its problems. One, it’s not as supple as Dacron, and it will readily slice unprotected fingers or hands. And it’s more brittle than Dacron, which can lead to failures in backing to fly line knots.

Fortunately, there’s a new backing material now available that can be a single backing solution for all the issues and requirements discussed above. More on that in my next post.