Fly Tying Videos
Fly Fishing Podcast
FFOhio Team
Warm Water Rivers
Flatwater Guides
Site Map


A Question of Balance, Part 2

By Joseph D. Cornwall


Originally Published in Country Anglin' Outdoor Guide, Jan/Feb 2007


"The best and safest thing is to keep a balance in your life, acknowledge the great powers around us and in us. If you can do that, and live that way, you are really a wise man. ." - Euripides (484 BC - 406 BC)



In our last installment of “On The Fly” we explored the importance of physical balance in a fly fishing system.  System is the operative word, here.  No rod, no matter how expensive, will perform at its potential if it is mated with an inappropriate line or the wrong weight of reel.  While the reel doesn’t play a direct part in the act of fly casting, we discovered in the last issue that the fulcrum balance the reel provides in the context of the rod/reel/line system does have a significant impact on accuracy, distance and ease of cast-ability.  This time we’ll look at the mystery of the fly line and see if we can shed some light on a system that is both too rigid and yet not rigidly enforced enough. 


To understand line-rod balance in a contemporary fly fishing system we must understand a little bit of the history of fly fishing.  Years ago there were no numbers to define the line that matched the rod.  There were letters.  The letters corresponded to a diameter.  All fly lines were made of silk, so lines of comparable diameter had comparable weight.  Thus a rod designed for an HDH fly line tended to work well with most lines of that designation.  In the later half of the twentieth century, plastics came about and messed the whole system up.  Now fly lines made of synthetic materials could be much lighter that silk in the same diameter.  What’s worse, the design of the line – floating, sinking, intermediate, etc.. – had a direct effect on the mass of the line. An HDH sinking line might be heavier than an HDH silk line, but only half as massive as an HDH floating line.  It became almost impossible to select a fly line to match a particular rod without the option of casting several different examples.


In the early 1960’s the American Fishing Tackle Manufacturer’s Associations (AFTMA) created the system presently in use.  Numbers were assigned to describe the weight of the first thirty feet of the fly line, less the level tip.  Now we could be sure that a six weight line from one manufacturer would be similar to a six weight line from another.  They might differ significantly in diameter, stiffness or slickness, but they would weigh the same and thus load the rod similarly.  Here is the table that describes current fly line weights and their relationship to letters and to each other;



Avg Weight in Grains (a)

Range: Mfg Tolerances

Double Taper (DT)

Weight Forward (WF)






























































Looking at this you’d think it was all worked out.  Just match the number of the fly line to the number the manufacturer prints on the fly rod and you’re done, right?  If only it were so easy!


While there is a standard reflected above that describes the precise weight of the line, there is no matching standard to measure the flex of the rod when subjected to that weight. In other words, we got the lines all worked out but left the builders to decide for themselves which line was right for a particular rod.  And the pressures of the marketplace being what they are, the practice of providing a weight range was quickly dropped in favor of a single number.  Fishermen didn’t want to know their rod was a 4/5/6, they wanted to know which line to buy! Thus, logic dictates that the 4-weight 9-foot rod you just bought should work with a 4-weight, and only a 4-weight line.  This is where the system has become too rigid.


The problem is that single number, so precisely printed on the shaft of the gleaming high-tech graphite rod, is only a suggestion — not a rule!  Depending on your casting style, the distances you will normally be casting, the size and aerodynamics of the fly you’re going to present, and the wind and environmental factors associated with the presentation, that 4-weight fly rod may work better – much better – with a 5-weight or even a 6-weight line!  Conversely, magic might be made if the ersatz 4-weight is matched to a 3-weight line!  How can this be?


To understand this we need to understand how the fly cast works at a physical level.  The fly is not cast, of course.  The line is cast and the fly simply goes along for the ride.  The air resistance of the fly, which is also proportional to its size, slows the speed, also known as velocity, of the line down. This is why a leader doesn’t crack when you have a fly tied to the tippet but snaps like a bull whip when you don’t.  That snapping sound is actually the sound barrier being broken by the tippet as it changes direction at the end of the casting stroke – it’s a mini sonic boom!  This is precisely how a bull whip works, too.


A fly line carrying the fly to its target takes a curved path; the perfect loop we all try to achieve.  Any motion in a curved path represents accelerated motion and requires a force directed toward the center of curvature of the path. This force is called the centripetal force, which means "center seeking" force.  This centripetal force is made up of velocity and mass.  For the purposes of this discussion that means the line’s speed during the cast, and the line’s weight.


It takes a single, quantifiable force to deliver a specific fly to a precise target a certain distance away.  If you can deliver a size 8 woolly worm to a submerged rock at 50 feet with a 6-weight outfit, and you decide to make the same cast with a 4-weight outfit you will have lowered the mass of the line. Because of this you will have to increase the speed of the line to compensate.  To make the same cast with the lighter line you either need to increase the speed of your casting stroke (very difficult for most folks to do in a controlled manner) or increase the “speed” of your rod – go from a medium-fast to a fast action, for instance.  The faster rod flexes more towards the tip making for a longer lever.  The longer lever produces higher line speed.  The penalty is that all of this adds up to lower tolerances for timing errors.


The speed of your casting motion has to be compatible with the flex speed of the rod as loaded by the typical fishing length of line for the best results.  There are limits as to how fast a rod your particular casting stroke will allow.  f you have a very compact and vertical fly casting stroke then you’ll probably benefit from a faster action rod.  You can determine this by just thinking about where your elbow is when you are casting.  If your elbow is directly in front of you and you cast with an “up and down” motion you have a short casting stroke.  If your elbow is out to the side of your body then your stroke is proportionately slower.  If you match your casting stroke with the action needed from the rod to propel your fishing fly to its intended destination you’ll find great joy and ease in casting.  If you have a mismatched outfit – and by that I mean an outfit that isn’t matched to your casting stroke and fishing situation – you’ll suffer the frustration of short, inaccurate casts that don’t’ turn over, tailing loops or tangles.  In this case a mismatched outfit might just end up being a fast 4-weight rod coupled to a 4-weight line.  This is where the AFTMA system can be too rigid.  The books say it’s right but your satisfaction says it’s wrong!


And again, here come the pressures of the marketplace.  The advertising that promises “to push the boundaries of fast action tapers and high line speed,” may convince you to get more speed in a lighter line weight than you really need for effective everyday fishing.  The “underlined” rod doesn’t cast as comfortably at forty feet as it does at seventy so we assume the line is at fault. This creates a perceived need, which is then filled by fly lines “made half-size heavier to more fully load fast-action graphite rods.”  Doesn’t this sound suspiciously like we’ve increased the mass of the line in order to propel an air resistant fly to a precise target some distance away?  We had to do this because we couldn’t increase the velocity of the line any more.  One or the other has to be adjusted, that’s the laws of physics!


So with medium, medium fast, fast and extra fast action rods in all lengths, lines promising everything from incredible distance to delicate presentation, and the desire of all anglers to maximize the sport by selecting the lightest line size practical, what’s a poor fellow to do?  How can we fine-tune gear we already own, or select the best possible new gear to fit our fishing conditions?  The first thing we can do is ignore the single line size printed on the rod!  Let me give you two examples where moving up a line size from the manufacturer’s recommendation and moving down a line size from a manufacturer’s recommendation made a big difference in my gear.


My natural casting style is with my elbow about forty-five degrees to my side. I take a slightly open stance towards my target and my stroke is compact but not fast.  Medium action rods feel best in my hands for most fishing.  While chasing smallmouth bass on the super clear water of Twin Creek during late summer I came to the conclusion that the bass were feeding on tiny fry.  Streamers in size 12 were the only thing that would move fish, but I needed to make long, accurate casts tight to the rocks in the low, clear water.  I was fishing an 8 ˝ foot 5-weight rod.  The weight forward line, while easily capable of the distance, left a lot to be desired for stealth. Adding to the problem was that the rear taper of the WF line kept my false casts under 40-feet, which meant that I needed to shoot some 20-feet of line to hit the targets across the creek.  Fishing was tough.


After a couple of hours of frustration I went back to my car and took out the reel for my back-up rig, a 7 ˝ foot 4-weight.  Instead of using the 4-weight rod, which would have struggled for control at the 60-foot distances I was fishing, I strung up the 4-seight on my five-weight rod.  By dropping to a double-taper 4-weight instead of a weight forward 5-weight I was able to increase the amount of line I could comfortably carry in the air during a false cast.  Line speed increased, helping accuracy further.  My full flex 5-weight had just become a medium fast 4-weight!


There is an 8-foot glass rod I am recently evaluated for a review.  I really like the rod, but I couldn’t quite get it to work for me.  I fished it several times this autumn and always felt like I was working too hard to deliver the fly.  I was fishing small creeks, hitting the pocket water with Foxee Red Clousers.  Because of the broken water and close conditions most of my casting was inside of 40 feet.  The fly was hitting the water far too hard for a good presentation and I felt like my casting stroke was really being hurried.  My wrist was aching and my casts were deteriorating with a series of tailing loops.  I needed to slow my casting stroke and increase the mass of the line so it could control that heavy Clouser Deep Minnow at a lower velocity.  By moving from a WF-5 to a Bass Bug tapered WF-6, I managed to load the rod more deeply, slow its rhythm and increase the delicacy of the presentation.  This glass rod has become my absolute favorite smallmouth bass rod for distances inside of 50 feet when so rigged – and it remains formidable with a double taper 5-weight when I want to false cast 40 to 60-feet of line while presenting a small dry fly with accuracy and control.


In another instance my frequent fishing partner and Fly Fish Ohio editor Jim Stuard remarked that he’s had a 4-weight rod for some time that he just didn’t like.  As Jim tells the story; “I’d never been able to fish the … rod comfortably, and I asked Paul to take a look at it. In the space of five minutes he’d fixed the problem. The reel had a 4-weight Orvis Wonderline spooled up, and it cast like a brick. I thought it was my poor technique, but when Paul suggested a heavier line I loaded up the 5-weight…  Now that [rod] fires casts like bullets. Go figure.”


Most good fly shops have several test lines loaded on reels.  If you don’t own multiple outfits you should consider dropping in at your local outfitter and casting your rods with a line up and a line down.  Learn what over-lining and under-lining does to the action of the gear you fish.  And when you’re ready to buy new gear remember to look at that number printed on the rod as a suggestion.  Go shopping with an accurate estimate of the distance you normally cast and bring a fly typical of the flies you’ll ordinarily fish.  Cut the hook off at the barb and use that fly to test cast the rods.  Select a line based on how it affects the speed of your casting stroke and your ability to control the cast, not based on how far you can double-haul.  At the end of the day you’ll end up with a rig that’s balanced specifically for you and your needs.

© Copyright 2005 - 2010.  All rights reserved.  No portion of this web site may be reproduced in any fashion without the express written consent of Fly Fish Ohio.

Send email to the Webmaster   This page was last updated 08/09/10