“Weight in Gold: Line Weighting for Different Rods, Different Casts, and Different Strokes” – by Tyler Justice Allen

Line weighting is a contentious issue in the fly fishing world. Looking at the accepted standards developed by AFFTA eons ago, one would correctly assume that most fly lines produced these days are heavier than the standard dictates they should be. This a product of manufacturers producing ever-faster, powerful rods that require additional mass to load properly, but does a disservice to the casual angler who is more concerned with stated line size than grain weight over the first thirty feet of line. What’s better for the industry overall? Lines that match an accepted, albeit antiquated, standard or lines designed to load modern fast action rods but still receiving a lighter line size designation? As with most things in fly fishing, there are strong opinions on both sides.

Modern rod construction techniques have allowed manufacturers to produce faster, more powerful rods with less material than ever before. This provides low swing weight with quick tip recovery and the backbone to keep big fish pinned. The downside is that they often require a line that is a half to full size heavy relative to the AFFTA standard to load properly. Less material in the blank also often means that they can’t take quite as much of a beating as older, thicker blank walls. But that’s a different blog post.


Most manufacturers still produce medium-action rods, but they’ve been overshadowed by their faster brethren, regardless of how they fit an individual’s casting stroke. The fact of the matter is this: medium action rods have a larger ‘sweet spot’ and fit a wider range of casting strokes than fast action rods. Fast action rods are killer for anglers able to readily adjust their stroke length and hand speed, but don’t help most folks. For many beginning and intermediate anglers, fast action rods will steepen the learning curve and make casting more difficult than it needs to be. Fast rods are like IPA beers; people buy them because that’s what their friends and the market tell them they should buy. Do fast action rods actually fit your casting stroke? Do IPAs actually taste good? To some folks maybe, but not everybody.

Back to the issue at hand: line weighting. All things being equal, medium action rods typically do best with lines close to the AFFTA standard, while fast action rods like more mass. Should the AFFTA standard change to match modern fast action rods, so that a ‘standard’ WF8 line loads a modern fast action rod? Or should the standard remain the same with the express caveat that a WF8 line may not load your #8 single-hand fly rod? There isn’t a good answer here. From where I sit – and I admit that I’m in a privileged position with access to a bald, enigmatic encyclopedia of fly fishing knowledge at my disposal – it would make more sense if we just cut the BS and listed all fly lines with both total head mass and mass over the first thirty feet*. You can keep line size designations, just offer a dual line size rating with both mass measurements. It would look something like this for an overweighted line:

Airflo Super-DRI Xceed WF5/6

155 GR / 190 GR

Set up like this, the consumer would see that the line works on both #5 and #6 rods (depending on preferences, which we’ll get into in a minute) and has both mass measurements for folks that like to go Copernicus on their fishing gear. The main argument against just a grain weight designation without stated line size is the intimidation factor. Fly fishing is generally viewed as difficult – just learning to overhead cast a single-hander is seen as a significant accomplishment (and it is!). By removing a stated line size designation, folks would need a greater base knowledge of what weight loads a specific rod size of given action and power levels. Or, better yet, it would mean that folks would have another reason to tap the knowledge base of local fly shops… It would look something like this:

Airflo Super-DRI Xceed

155 GR / 190 GR

Marketing fly lines this way would also prevent ‘pigeon holing’ the lines into a specific line size. As a real-world example, many anglers fish 160 grain sink-tip lines (listed as WF5) on their #6 and #7 rods. So which is it? A #5, #6, or #7? Well, it’s all of them – it just depends on the rod’s action and the caster’s personal stroke.


Casting strokes can affect the ideal loading mass, as well. Faster, punchy casting strokes can often handle lighter lines while more fluid casting strokes will typically do better with a bit more mass. Going with a lighter line can ‘speed up’ a rod’s action, making it feel faster than designed. Underlining by a full size can make a rod feel significantly faster, while overlining can slow a rod’s action down to allow the caster to feel the rod load and know when to press the ‘GO!’ button. It’s good to remember a previous lesson: it takes mass to turn over mass; overweighted lines are generally offer greater turnover power relative to lighter lines. What works for you may not work for your buddy, and vice-versa. The best piece of advice? Examine your own casting proclivities and decide what feels best to you. Do you have a punchy casting stroke and are consistently throwing tailing loops? A faster-action rod or lighter line could help. Are you having trouble feeling the rod load and mastering cast timing? A medium-action rod or heavier line may be just the ticket.

Different types of casts require different amounts of mass to load a given rod. An overhead cast requires about 60 fewer grains than a sustained-anchor (Skagit) cast to load. From a two-handed casting perspective, this means that your regular Skagit head that you use for spey casting probably isn’t the best option for overhead – it’s just too heavy. During an overhead cast, the entire aerialized portion of fly line is loading the rod (including the sink tip if applicable). Conversely, during a sustained anchor cast, only the portion of line above the waterline and in the D-loop is loading the rod. More on that can be found here. The concept is the same when talking about roll casting with a single-hander: roll casts require more grains to load the rod than an overhead cast. If you plan on primarily roll casting with a specific rod/line setup, you may benefit from an overweighted line.

When converting between single-hand line designations and two-hand designations, it’s generally appropriate to add 2 to 3 line sizes to find an appropriate match for a two-hander (the ECHO Boost Beach and some other surf rods are notable exceptions). For example, a #7 two-hander would load with a WF9 or WF10 standard single-hand fly line. This is a useful tool when looking for an overhead casting line for a two-hander in the surf or elsewhere.

Line weighting will continue to be a to be fodder for campfire conversation, regardless of how boxes are labeled. What’s important is realizing that all WF5 lines are not created equally. Learn about your own casting stroke and what YOU like, not what your buddy likes. After all, not everybody likes fast rods and IPAs.

 *Measuring mass over the first 30 feet of a fly line allows for a uniform measurement across lines with varying head lengths. Some heads may be as short as 25 feet, while others may be as long as 55 feet. A 225 grain line @ 25 feet is going to load a rod differently than a 225 grain line @ 55 feet.

Photos: Justin Edge (@justin.edge.photography)

Tyler Justice Allen is the Marketing/Pro Team Manager for Rajeff Sports. He directs the Fish Need Water Alliance conservation program (FishNeedH2o.org) and owns a stewardship-oriented fly fishing guide service based in Northwest Oregon. When he’s not on the water, you can find him climbing, tinkering, or spending time with his lovely wife, Lauren. 

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