Getting started: Rod weights and line weights

A small-stream native cutthroat trout caught using a 1-weight fly rod. Photo by Chris Hunt.

Editor's note: This is the latest installment in a series of posts designed to help new fly fishers get started in the craft. 

In previous posts, we've recognized that the fly-fishing world is a tough nut to crack, just from the ease-of-entry standpoint. New fly fishers are faced with a complicated system of metrics that often don't make much sense, and, often, nobody is available to make metrics understandable to someone coming to the sport from gear fishing or, especially, for someone starting fly fishing cold turkey. 

We'll take it slow, and start by making the complicated rod- and fly line-weight system easier to grasp. 

First, when choosing a fly rod weight, you need to determine two things:

• How big are the flies you're going to cast?
• How big of a fly line do you need?

Unlike hooks and flies, where higher numbers are assigned to smaller flies, rods and lines are exactly the opposite. The smaller the number, the lighter the rod, and the smaller (in diameter) the fly line. If you're going to chase trout on small streams, you likely want a fly line that can cast dry flies and nymphs (and maybe small streamers). If you're going after redfish on the flats of south Texas, you'll want a fly line that will throw big saltwater flies and cut through the wind. In other words, you'll want a lighter rod/line for trout, and a heavier rod/line for those reds. 

Generally speaking a 5-weight fly rod/fly line combination is considered "standard," for lack of a better term. A 5-weight rod equipped with a 5-weight line can turn over bigger flies, cut a modest breeze and still present a dry fly with reasonable delicacy and accuracy. If you're a trout or a bass angler and you're into throwing heavier flies like weighted Woolly Buggers, foam poppers or bigger streamers, you might consider moving up to a 6-weight. If you fish smaller water for trout, and you need delicacy and accuracy, you might drop down to a rod/line combo as small as a 3-weight, or even smaller, depending on the conditions and the size of the flies you'll be casting. And one tip: Don't let anyone tell you that light rods are just for small fish—I've caught 20-inch rainbows in small water on small flies casting a 2-weight rod. It's not about the fish, per se, but more about the size of the fly you're using, and the size of the line needed to cast that fly.

This is one area where the proprietor at a local fly shop can be very helpful. If you give him or her all the information you possess, i.e., "I want to chase brook trout on dry flies on small streams in Virginia," you should be able to leave the shop with perfect rod/line combination for that particular fly-fishing discipline (I'd recommend a 2- or 3-weight in that instance).

For even more clarity, check out this video rom Orvis' Tom Rosenbauer, who actually shows you how fly lines differ and how rods are designed with certain lines in mind. It'll give you an even better foundation from which to begin choosing your fly-fishing outfit. 

— Chris Hunt

Other posts from the "Getting Started" series: 

• Getting started: Fly sizes
• Getting started: Know your trout
• Getting started: From gear to fly
• Getting started fly fishing