Older Fly Rods and Their Line Weights

Since I have started collecting vintage fiberglass fly rods, I have discovered that they used a different coding system for telling the angler what line weight the rod was designed to be fished with.  I have been asked a few times to tell people what line weight their old rod will work best with.  Since I have often used a chart such as the one below, I decided to share it here in case others might find it helpful or interesting.  So, without further ado, here is a chart showing how to convert older fly line weights:

AFTMA fly line weights - conversion to "old style" letter designations (best estimate)

AFTMA No.	Avg Weight in Grains (a)	Range: Mfg Tolerances	Double Taper (DT)	Weight Forward (WF)	Level (L)
2	80	74-86	IHI	IHJ	H
3	100	94-106	IGI	IGJ	G
4	120	114-126	HFH	HFG	F
5	140	134-146	HEH	HEG	E
6	160	152-168	HDH	HDG	D
7	185	177-193	HCH	HCF	C
8	210	202-218	GBG	GBF	B
9	240	230-250	GAG	GAF	A
10	280	270-290	G2AG	G2AF	2A
11	330	318-342	G3AG	G3AF	3A
12	380	368-392	G4AG	G4AF	4A
13	430	418-442	-	-	-

(a) Per 3M Worldwide / Scientific Anglers(tm), based on first 30 feet of line, exclusive of front level tip. (1 oz. = 437.5 grains)

Chart is courtesy of the Fly Fishing Forum and can be found at www.theflyfishingforum.com