The Complete Guide to Setting Up a Fly Reel: From Backing to Fly Line

There's a particular satisfaction in rigging your own fly reel — threading the backing, tying the knots, and winding everything on with care, knowing that when a fish finally takes your fly, every inch of that setup is your own handiwork. For many anglers, especially those just entering the world of fly fishing, the process can feel intimidating. But according to Chris from Bow River Troutfitters, it's far more approachable than it looks.

"Eventually you're going to have to do it yourself, or you're going to want to do it yourself," Chris explains. "This is something you can absolutely do at home, just given a little bit of time and patience — and you certainly don't need any fancy equipment."

Using a Redington Run reel in a 5/6 size and standard 20-pound Dacron backing, Chris walks through every step of the process — from understanding your reel's mechanics to making professional-grade loop connections. Whether you've just purchased your first fly reel or you're looking to sharpen your rigging skills, this guide covers everything you need to know.

Step One: Know Your Reel Before You Begin

Before a single piece of backing is tied or a knot is formed, it pays to spend a moment understanding the reel in your hands. Two details, in particular, deserve your attention right from the start: retrieve direction and cage design.

Setting the Retrieve Direction

Most fly reels come from the shop configured for left-hand retrieve, which suits the majority of anglers. However, if you prefer to reel with your right hand, you'll need to reverse the drag system before rigging begins. Trying to change retrieve direction after the line is already on is a frustrating exercise best avoided entirely.

"Most reels come from the shop set up for left-hand retrieve," Chris notes, "but if you like to reel with your right hand, make sure that you reverse the direction. There's usually instructions with your reel, or the fly shop you buy it from should be happy to set that up before it goes out to you."

Open Cage vs. Closed Cage Reels

The second consideration is one that catches many beginners off guard: the difference between open-cage and closed-cage reel designs. On an open-cage reel like the Redington Run, the spool pops out freely by pressing the center button, and you can attach your backing directly before snapping it back into place. Simple and intuitive.

Closed-cage reels — such as the Sage Trout referenced in Chris's demonstration — are a different matter. The interior is sealed, meaning any backing that hasn't been threaded through the cage opening beforehand will become pinched between the metal frame when the spool is reinserted. The fix is straightforward: always thread your backing through the cage hole first, then proceed to attach it to the spool.

"If you have a closed-face reel, just make sure the backing goes through the hole of the cage and then out before you attach it around your spool. That way, when you put everything back together, it'll be coming through that hole the way it's supposed to."

Step Two: Attaching the Backing with an Arbor Knot

With the reel configured and the retrieve direction confirmed, it's time to attach your backing to the spool. The knot used here is called the arbor knot — a simple, reliable hitch that secures the backing to the center of the spool. It's worth noting upfront that this knot is not designed to fight fish. Its sole purpose is to anchor the backing so it doesn't spin freely on the spool hub.

"It's a very basic knot — not designed to hold fish," Chris clarifies. "If you get to the point where all your fly line and backing is out and this is all that's going to stop it, you just want to hold on tight and let the fish break off the mono. Otherwise, you're going to lose your whole rig."

How to Tie the Arbor Knot

Begin by tying a simple overhand knot at the very tip of the backing, trimming the tag end to just a few millimeters above the knot. This small stopper knot prevents the line from slipping through later. Next, wrap the backing around the spool arbor twice, then bring the main stem of the backing and the tag end together and tie a second overhand knot — making sure to capture the main stem inside that knot. Pull the whole assembly tight, slide it down toward the spool, and you'll have a secure slip-knot arrangement that cinches down firmly against the arbor.

A Pro Trick: Use Your Rod to Spool the Backing

Before attaching the backing to the spool, Chris shares a clever technique that makes the entire winding process cleaner and more controlled. Thread the backing through the first stripper guide — the large guide closest to the reel seat — before tying anything. You don't need to rig the entire rod, just enough sections to get that guide in play.

"I actually grab my fly rod and feed the backing through the first stripper guide before I attach it to the spool," Chris explains. "It lets me hold on to something more securely than just the reel while I'm winding, and it means the backing is always coming from one consistent direction — which helps you get a much tighter, more even wrap."

Step Three: Winding on the Backing Evenly

Winding backing onto a reel might seem like the most mechanical — and least interesting — part of the process, but it deserves real attention. Backing that goes on unevenly, with clumps built up in one area, creates a ticking time bomb inside your reel. On a calm afternoon pond, it might never matter. On a river, with a strong fish running hard, those lumps and tangles can cost you everything.

"When we're winding on our backing, we want some tension on it, and we want it to go on evenly — back and forth," Chris emphasizes. "You really don't want to build up backing over itself in one spot. It's going to slip and catch, and if you're in a situation where you've got a fish of a lifetime, you definitely don't want it to knot up inside the reel."

For tension, Chris uses a practical trick: sliding the backing spool under his leg while seated. The weight of his body provides just enough resistance to keep the line taut as it travels up through the stripper guide and onto the reel. If you're working from a smaller pre-cut spool sent by a fly shop rather than a commercial bulk spool, place it inside a small bowl or box so it can spin freely without unraveling across the floor.

Guide the backing back and forth across the spool with two fingers as you wind, distributing it in smooth, even layers from one side to the other. Take your time. There's no shortcut here that doesn't come with consequences later on the water.

Step Four: Understanding Reel Capacity

Once the backing is on, it's tempting to simply keep adding line until the reel looks full. Resist that instinct. Reel capacity is a nuanced subject — one that even experienced fly shop staff navigate carefully.

"This is a tricky thing, even for us in the fly shop as experts," Chris admits. "All sorts of reels from different manufacturers have different capacities. We're using 20-pound Dacron today, but sometimes you might want 30-pound Dacron or gel spun, and those all take up different amounts of space based on how thick the backing actually is."

The weight of the fly line itself also factors in. A five-weight line takes up measurably less space on a 5/6 reel than a six-weight line. To navigate this, Chris recommends checking the manufacturer's website for your specific reel's recommended backing capacity — and then intentionally using slightly less than suggested.

"For trout fishing, you just don't need a ton of backing. You're rarely ever going to get into it. I've certainly never had a trout take 75 yards of backing off my reel. When you go a little bit less on capacity, it gives you more physical space for different fly lines — and you don't want your leader knots banging up against the top of the reel every time you wind it in."

The goal is a reel that has adequate backing for emergencies, a properly seated fly line, and just enough breathing room that knots pass cleanly over the spool rim without catching. Overfilling is a common beginner mistake with very real consequences on the water.

Step Five: Creating a Loop on Your Backing

Modern fly lines have largely done away with the nail knot connection between backing and fly line in favor of a loop-to-loop system. This approach is faster to assemble, easier to reconfigure, and perfectly adequate for virtually all trout fishing scenarios. To make it work, you'll need a loop on the end of your backing.

In the fly shop, Chris and his colleagues use a Bimini twist to form the backing loop — a specialized knot that provides a degree of shock absorption valued in saltwater and big-game applications. For most trout fishing, however, it's engineering overkill.

"A double surgeon's loop is very easy, very simple, and it's going to work just fine," Chris says. "You don't need the shock absorption that a Bimini twist provides for trout."

Tying the Double Surgeon's Loop

Double the backing back over itself to form a loop, making sure the loop is large enough to pass a fly line spool through — you'll need that clearance to complete the loop-to-loop connection later. Hold both strands together and tie a double overhand knot — essentially an overhand knot where you pass the loop through the opening twice before pulling tight. Moisten the knot, draw it down slowly and evenly, and trim any excess. The result is a clean, strong loop that will handle anything a trout can throw at it.

Step Six: Building a Loop on the Fly Line

Most contemporary fly lines arrive with a factory-welded loop at the rear (backing) end, making connection simple and immediate. But occasionally you'll encounter a line without a loop, or one whose loop has cracked, peeled, or otherwise failed after seasons of use. In those cases, knowing how to build your own nail-knot loop is an invaluable skill.

Chris demonstrates a method using two back-to-back nail knots tied with 12-pound monofilament over a folded section of fly line — creating a loop that's exceptionally strong and unlikely to fail under any realistic trout fishing pressure.

Tools You'll Need

The essential tool here is a nail knot tool — a small, inexpensive instrument available at any fly shop that makes forming and tightening nail knots dramatically easier. You'll also need a length of strong monofilament, around 12-pound test, to form the wraps that bind the loop in place.

The Nail Knot Loop Process

Fold the tip of the fly line back over itself to create the desired loop size. Lay the nail knot tool alongside the folded section and wrap your monofilament around both the tool and the fly line in six or seven tight, concentric turns, working back toward your hand. Pass the tag end of the mono through the nail knot tool from left to right, then slide the tool out while pinching the wraps firmly in place — a critical step that keeps those wraps from loosening before you can tighten them down.

Pull both ends of the monofilament with steady, even pressure until the wraps cinch tightly around the fly line. Inspect the wraps to ensure they're laying neatly side by side, then repeat the entire process with a second nail knot positioned immediately adjacent to the first. Trim all tag ends flush, and the loop is essentially complete.

"One single nail knot will hold this loop against pretty much anything — but to be safe, I do the exact same thing right next to it. That way, it's totally secure."

Finishing with UV Knot Sense

For a professional finishing touch — and genuine functional benefit — Chris applies a small amount of UV-curing gel, such as Loon's UV Knot Sense, over the nail knot wraps and, crucially, over the trimmed end of the fly line below the knots. When a fly line is cut, the exposed end can wick water into its core over time, causing the line to waterlog and sink. Sealing that cut end prevents moisture intrusion entirely.

A few seconds under a UV light cures the gel completely, leaving a smooth, hard finish that passes through rod guides cleanly and protects the knot from abrasion. It's a small detail that makes a meaningful difference, particularly on the leader end of the fly line where performance matters most.

Step Seven: Completing the Loop-to-Loop Connection and Loading the Fly Line

With loops formed on both the backing and the fly line, the connection itself is elegantly simple. Pass the backing loop through the small loop at the rear of the fly line, then feed the entire fly line spool back through the backing loop before pulling everything snug. The result is a neat, interlocking connection — what fly anglers call a loop-to-loop — that can be undone and reconfigured in seconds if you want to swap fly lines for different conditions.

With the connection made, the fly line can be wound directly onto the reel. At this stage, Chris opts to forgo the fly rod setup used for the backing.

"This part is much easier without the rod," he notes. "I still want to make sure the fly line goes on evenly, but it's just not as critical — especially if you've left yourself that extra capacity we suggested."

One important caution: ensure the fly line comes off its spool without introducing twists. Loops and coils wound onto the reel will create tangles and wind knots that plague your casting. Always wind from a proper spool — never from a loose pile — and guide the line evenly back and forth with your fingers as you reel it in.

The Finished Product — and Why It's Worth the Effort

Done properly, a well-rigged fly reel is a thing of quiet craftsmanship. The backing sits tight and evenly distributed. The fly line follows without crowding the frame. There's room for the loop knots to pass freely over the spool rim, and space at the top for a leader and tippet without any risk of jamming.

"It looks like a beautiful watermelon," Chris says with evident satisfaction. "Not overcrowded — we've still got lots of space to put on a leader and tippet. That's the end result we're hoping for."

The skills involved — the arbor knot, the double surgeon's loop, the nail knot — are ones that every fly angler should have in their repertoire. They take minutes to learn and a lifetime to appreciate, especially in those moments on the water when everything needs to work perfectly. Rig it right at home, and you can focus entirely on the fish when it counts.