Fly Line Backing Advice & Opinions

Choosing the correct backing for your specific fly fishing need prevents problems. Large diameter line backing means less reserve line under your fly line. This limits your control of a large, far-running fish because the fish can take all your line out and break off when it hits the end of the backing. Filling a fly reel with the more expensive small diameter line backing means unnecessary expense. Making the right choice will save your money and help land more fish.

  1. Fly Line Backing Choices

    • There are two predominate types of fly line backing available: braided Dacron and gel-spun. Braided Dacron is a fairly common material and is also found in many applications such as soda bottles and sails for sailboats. Gel-spun is also found in items such as climbing ropes and body armor.
      Braided Dacron, made of a polyester material, in the 20-pound range is the best choice for most trout fishing. Other kinds of angling, such as salmon or steelhead fishing might require 30-pound backing to fight these stronger, larger fish. If a heavier backing is required, less of it will fit on a reel.
      Gel-spun is the other major choice for backing. This is made of a high-modulus polyethylene, not Dacron. The advantage of gel-spun is in its higher strength-to-diameter ratio. As a result, this is often the choice for saltwater fly fishers because they can fit up to 80 percent more gel-spun backing as compared to equal test Dacron backing. This gives more protection for landing fish that will run much longer distances, a common occurrence in saltwater fishing.

    Less Desirable Alternatives

    • Some fly fishers use monofilament as fly line backing. While this is an inexpensive alternative it does not perform as well as either Dacron or gel spun. Monofilament has a tendency to roll over on itself and create a knot that stops the backing from running off the reel. When a large fish is pulling line off the reel, this knot causes the bind and allows the fish to break off.
      One or two-weight floating fly lines are sometimes used as backing. They work better than monofilament but are costly. Another disadvantage of the lightweight fly line when used as backing is the limited length. At 90 feet, they offer little advantage compared with the longer lengths available in Dacron or gel-spun backing.

    Other Considerations

    • Fly reel manufacturers provide recommendations for how much backing should be used with each of their models. Follow the manufacturer's recommendations. Too much backing will cause the fly line to bind up in the reel and prevent the fish from smoothly taking line. This binding acts as increased drag and can cause the fish to break off.
      In the absence of manufacturer's recommendations, you can fill the reel with the correct amount of backing by winding the fly line on first, followed by the backing, stopping when the spool is full but not over-full. Then take the line and backing off and switch them so the backing is wound on first, followed by the fly line.