Choosing The Correct Fly line

We have had many requests regarding the correct selection of both silk and modern synthetic fly lines. The following information will help you choose a fly line that will cast well with your bamboo fly rod. We have also included a conversion chart of the old line designations that are often found on older bamboo fly rods.

We want to thank Mike Brookes, the owner of Phoenix Fly Lines for allowing us to use this very helpful article that he wrote on the subject of selecting the proper fly line for your cane rod.

Feel free to contact us if you have any questions on this subject or if there is something else you need to know. If we can't answer your questions, we will find someone who can!

Line Weights by Mike Brookes

The AFTM scale gives weights to lines from #1 to #12 and is based on the first 30 feet of line. Rod builders use this to specify the correct line for the rod to obtain maximum performance from that rod.

Generally, the line size specified by the rod builder will be the most suitable for that rod. However, the weight at which a line performs depends on the length of the cast.

Each line size has a range of weights to allow for manufacturing tolerances. This is true for both silk and synthetic lines. These are listed in detail at Note 1.

An example
A #5 line weighs 134 – 146 grains
At 146 grains, 30 feet of line gives 4.866 grains per foot (146/30)
At 134 grains, 30 feet of line gives 4.450 grains per foot (134/30)

The longer the length of line aerialised, the greater the weight acting on the rod.
Aerialise 32 feet of line
At 146 grains, 32 feet of line gives 4.866 grains per foot equals 155.73 grains
Thus the #5 line at the heavier ends performs as a #6. (152-168 grains).

The shorter the length of line aerialised, the lesser the weight acting on the rod.
Aerialise 28 feet of line
At 134 grains, 28 feet of line gives 4.450 grains per foot equals 124.60 grains
Thus the #5 line at the lighter end performs as a #4. (114-126 grains)

Matching a line to a rod
When matching a line to a rod, for optimum conditions, take into account the rod builder's size designation and the conditions under which you fish. If, for example, when habitually aerialising 36 – 45 feet of line, then go down at least a line size (#5 down to #4). On small streams casting 18 – 24 feet, then, for #5 rod go up to a #6 line.

There is no doubt that the correct matching of line to rod to fishing conditions will make life considerably easier. Fly rods normally have a good tolerance to under or over-lining in fishing conditions.

As a general guide, for long distances favour a line lighter than specified and for short distances you would be better balanced by picking a line heavier than indicated on the rod.

The weight of any fly or lure that one might be using can also affect the way in which a line performs. For example, the weight of a size 12 gold head nymph could add about 5 grains.

Note 1
AFTM Code    Weight         Range
                                        From To
    1                   60             54 - 66
    2                   80             74 - 86
    3                  100            94 - 106
    4                  120            114 - 126
    5                  140            134 - 146
    6                  160            152 - 168
    7                  185            177 - 193
    8                  210            202 - 218
    9                  240            230 - 250
    10                280            270 - 290
    11                330            318 - 342
    12                380            368 - 392

Thank you Mike for the above information!

The history, creation process and care of silk fly lines is a very interesting topic. Mike Brookes has written a very interesting regarding this subject. Here is a link to that article: Silk Line History and Care

    All rights reserved - This site was designed, built and is maintained by A. B. Herndon  Unless otherwise noted, all photographs were taken by A. Bruce Herndon.