At a Glance: Fly Line Backing
FishUSA offers fly line backing from RIO, Scientific Anglers, and Cortland, and we stock backing in 20, 30, and 65-pound ratings in orange, yellow, and white colors. The most common backing material is Dacron for its durability and cost-effectiveness. Backing comes in 100 and 250-yard spools, with gel spun backing offered in larger yardages.
The reason for backing on a fly reel is two-fold. First, backing fills up the reel's arbor to a larger diameter before mounting the fly line onto the reel, aka spooling. The arbor on standard and mid-arbor reels is small. When wound, the fly line coils tightly around it, and today's lines with nylon cores and PVC coatings want to retain that circle shape, which interferes with casting performance and creates tangling. Backing helps reduce line coil "memory." Although line memory is not much of an issue with large arbor reels, backing lines are advised for this reason. Second, the backing is also necessary when fishing for larger freshwater species and almost all saltwater species. When hooked, these larger fish take a line off the reel very fast, and 90 feet of fly line will be out the rod tip in a few seconds. The backing extends the fly line, maintaining contact with the fish until it can be reeled in and landed.
In most cases, you should always put at least 50 yards of backing on a freshwater reel and 100 to 250 yards on saltwater reels.