When your ‘#5’ is actually a #5.5, #6, #7..or an #8

When your ‘#5’ is actually a #5.5, #6, #7..or an #8

Nick Moore | Tuesday, 27 April 2021

The AFTMA industry standard (now known as AFFTA) has been around for a very long time. It was invented around the 1960’s by Myron Gregory, and it is a very simple system. The first 30’ of fly line, minus the level tip, should weigh a specified amount (in grains), with tolerances either side of the target weight. For example, a #5 must weigh between 134 and 146 grains, with a target weight of 140 grains, and we call lines that follow the AFFTA standard ‘true to weight’ lines.

Line manufacturers are making lines that are overweight, which means they are heavier than the industry standard, so what you see on the box is not always what you get! Why do they do this? It is often quoted that the increased weight ‘loads faster actioned fly rods’. Well, it does load them more, but it’s a big misunderstanding about how casting works. The rod doesn’t work as a giant spring that propels the line, it is mostly a flexible lever that lets us move the line as straight as possible. The heavier line DOES give the rod a different feeling, but then as Paul says “you’ve bought the wrong rod!” We choose tackle by deciding on the biggest fly we will use, and go backwards from there. The rod is actually the last thing in the sequence. For distance casting you actually want LESS bend, which means less counterflex. Less counterflex gives the caster a tighter loop and more line shoot. The heavier lines go further because they have more mass. Now, a fly line that says ‘#5’ on the box could be a true #6, #7, or an #8, or even a ‘half weight heavy’. What is the point of that?! Fishing wise, this presents a big problem. If you want to fish size 20-22 flies effectively, for example, then you'll need a #4 line that's true to weight. If it says #4 on the box but it's really a true #6 or #7 then you are going to straighten the small hooks and/or snap the light tippet with the heavy line. You won't be able to see or feel the take very well either.

However, this FP is about measuring fly lines and starting to build the database! Now, as we know, the weight of a fly line is determined by the first 30’ of line, minus the level tip. Not may lines come with a level tip anymore, so the easiest way to measure them (that I’ve found) is to measure from the tip of the welded loop, or if your line doesn’t come with one, the very tip of the fly line. Measure 30’ very accurately from this point and weigh it. Now, I needle knot a tapered leader to my lines, but I cut them all off to measure the weight to make it easier. So, what equipment do you need and how do you do it?

  1. A class 2 tape measure (I use a Stanley Fat Max)
  2. 2. Salter Precision micro digital kitchen scales (0.05g resolution up to 500g) £19.99 check the scales with a few different coins
  3. 3. Electrical tape

How to

After extensive testing, I found that having the turn of line connected to the reel, gave the most accurate results when it was on top of the coil stack, I checked this by cutting up some old lines (so it was untethered), and they weighed exactly the same. Stretching the line also made no difference to the weight.

Step 1

You can measure 30’ however you like. But my personal favourite method is to use 5’ arm lengths against the tape measure. Place the welded loop on the true zero hook and make sure it is exactly at the end. You can then measure your 30’ from this point.

Step 2

Place a small piece of electrical tape at 30’ and coil the line up around your fingers, starting some 6” ahead of the tape, towards the tip. For best results, I’ve found that a coil diameter of 2” works the best. When you get to the tip of the line, wrap it around the coil to hold it together, just like how tapered leaders are packaged.

Step 3

Place your scales on a level surface, away from draughts, zero them, and check them with new coins to see if they are accurate. After you have done this, place the weighing tray to the right of the scales and place your coil of fly line on top. Make sure that the last coil (closest to the reel) is on top of the coil stack. Now, your 30’ mark should rest on top of the right-hand side tray edge, and the rest of the fly line should be in a relaxed curve, it shouldn’t be twisted, as this will give you a false reading. After you have measured, take the coil off the scales and check that they return to zero, and place it back on. Please see the photo below.

line_weights

Step 4 

There is no number 4 on SL

Step 5

Repeat steps 1-3 4 times, and work out the average for that particular line. Then convert your grams to grains. You can then see what lines you really have.

My Lines

SL Thunderbolt #5

8.95g

9.00g

9.05g

9.00g

Average = 9.00g or 138.89gr (true to weight)

 

SA MED #5 with loops

9.35g

9.40g

9.30g

9.35g

Average = 9.35g or 144.29gr (true to weight)

 

Ballistic Pro Performance #5

9.20g

9.15g

9.25g

9.20g

Average = 9.20g or 141.98gr (true to weight)

 

 

Rio in touch single handed spey #5

12.15g

12.05g

12.00g

12.05g

Average = 12.06g or 186.11gr (overweight, true #7)

 

SL Thunderbolt #6

10.40g

10.30g

10.40g

10.45g 

Average = 10.39g or 160.34gr (true to weight, perfect)

  

SL Thunderbolt Lumi-line #6 

10.70g

10.90g

10.85g

10.75g

Average = 10.80g or 166.67gr (true to weight)

  

Ballistic Pro Performance #6

10.20g

10.30g

10.20g

10.35g 

Average = 10.26g or 158.34gr (true to weight)

  

Greys platinum shoot #6

11.45g

11.35g

11.45g

11.50g 

Average = 11.44g or 176.55gr (overweight, between #6 and #7)

 

Rio Technical Trout #6

11.00g

10.80g

10.75g

10.75g

Average = 10.83g or 167.13gr (true to weight)

 

Barrio SLX #6

13.90g

13.80g

13.75g

13.80g 

Average = 13.81g or 213.12gr (overweight, true #8)

 

Rio In touch single handed spey #6

13.55g

13.45g

13.50g

13.60g

Average = 13.53g or 208.8gr (overweight, True #8)

 

SA MED #6

10.30g

10.25g

10.35g

10.30g

Average = 10.30g or 158.95gr (true to weight) 

 

SA MED #7 with loops

12.00g

11.95g

12.05g

12.00g

Average = 12.00g or 185.19gr (true to weight, perfect)

 

Ballistic Pro Performance #7

12.05g

12.00g

12.00g

11.95g

Average = 12.00g or 185.19gr (true to weight, perfect)

Here is a copy of the AFFTA table (for reference) from the SL website, print it out and have it to hand, it’s a useful table! The official approved fly line weights can be found here;

https://affta.org/page/IndustryStandards

aftta

All the best!