Backing vs More Fly Line (2026)
Backing is cheap line that fills the spool and gives you reserve if a fish runs beyond your fly line. Fly line costs many times more per yard and is not designed for that job. Every reel should be filled with backing then fly line, and for trout you will rarely see the backing, which is not a reason to leave it off.
At a glance
| RIO 20 lb Dacron Fly Line Backing | SF Large Arbor Fly Reel 5/6wt | |
|---|---|---|
| Cost per yard | Very low | Not applicable |
| Reserve for running fish | Yes | Not applicable |
| Fills the arbor | Yes | Not applicable |
| Increases retrieve rate | Yes | Yes, large arbor |
| Reduces line memory | Yes | Yes |
| Needed for trout | Rarely used, still fit it | Not applicable |
Choose the RIO 20 lb Dacron Fly Line Backing if…
Always. Backing costs almost nothing, fills the spool so the fly line coils less tightly, and is there on the day a fish does run. Have a shop spool it if you are unsure of the knots.
Check RIO 20 lb Dacron Fly Line Backing on Amazon
Choose the SF Large Arbor Fly Reel 5/6wt if…
The reel and the backing are one system: the arbor size and the backing together determine how tightly your fly line sits and how fast you can retrieve.
Check SF Large Arbor Fly Reel 5/6wt on Amazon
Related
Comparison based on published manufacturer specifications and the general consensus of owner reports. We have not tested these products side by side. Confirm current specifications and prices before buying. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
Reel capacity is where this decision actually gets made, and most listings do not tell you. The Redington Behemoth review is the exception: Redington publishes 125 yards of 20 pound for the 5/6 size, which lets you buy backing rather than guess. The Lamson Liquid and the Orvis Clearwater reel are the two sealed drag options at similar money.
Frequently asked questions
How much backing do I need?
Enough to fill the spool under the fly line, which varies by reel and line weight. Reel manufacturers publish capacities, and a shop will spool it correctly in minutes.
What knot joins backing to fly line?
Commonly an albright or a loop-to-loop connection if the line has a welded loop. Loop-to-loop is easier and lets you change lines quickly.
Does backing wear out?
Slowly, and it is worth inspecting when you change line. Dacron lasts a long time; check for abrasion near the arbor.
How we choose: we compare published manufacturer specifications, line and leader standards, and verified owner reviews across retailers. We do not test gear in person, and every diameter, grain weight and breaking strength quoted here is the manufacturer's published figure unless we say otherwise, so check the spool label before you trust a number. Nothing here is professional instruction. Wading moving water is the real hazard in this sport: wear a snug wading belt, know the water temperature, and turn back rather than push through a crossing you are unsure of.
