A few weeks back, I posted a review of the new Winston Alpha+ 7 weight which can be found right here. While seemingly pretty minor, one feature I really appreciated was that rather than just displaying the rod's line weight, Winston takes it a step further and lists the ideal line grain weight for each rod.
Why does this matter so much? Let me explain....
Fast and extra-fast action fly rods are extremely popular these days. I'm a fan of both, so I totally get it. Thing is, often times these rods perform a little (or a LOT) better with fly lines that have some added physical weight since it helps them load better. For reference, AFFTA (American Fly Fishing Trade Association) has set industry standards for how many grains each line size should weigh, as seen below....
Judging by this chart, things seem pretty simplistic, right? If you grab a 6-weight line it'll have a certain weight in grains, an 8-weight will weigh within a specific range, etc. Well, that's not always the case. Fly lines come in a ton of different configurations these days, and one of the changing variables is the grain weight of the line.
While the grain weight for a specific line can indeed closely follow the chart above, many fly lines of today have grain weights that fall into line weights one or even two sizes heavier. For instance, a certain 5-weight line might have a 30-foot head weight (remember, fly lines are measured for grain weight in the first 30 feet) of 160-grains which seemingly should make it a 6-weight line if following industry standards. Thanks in part to the rise of fast and extra-fast rods, manufacturers don't always follow the above specs anymore when labeling fly lines.
Let's look at our friends over at RIO who make a boatload of different lines....
Their WF5F Gold line has a 30-foot head weight of 146-grains which is within 5-weight specs, while their WF5F Grand line has a 30-foot head weight of 160-grains which is spot-on to what a 6-weight line should weigh per AFFTA standards. So, both 5-weight lines, but totally different grain weights. In this case, the lighter Gold line would be better suited to softer 5-weight rods and more average presentations, while the Grand line is the better pick for faster 5-weight rods and increased casting power for wind, larger flies, etc. You can almost think of these lines like a pair of running shoes and hiking boots you might have in your closet—both are the size you need, but both have different purposes they excel at.
The differences in fly line weight can cause confusion to the uninformed consumer who might think that any good line matching the rod's line rating will be the optimal choice. It's not like your fly rod won't perform at all if you don't choose the line with the best grain weight, but the right line allows the rod to perform at its very best. This is why it's always important to not just look at the line weight number, but read the line's description and find out the physical grain weight so you can see where it fits into the AFFTA chart.
There are already some fly rods on the market rated for specific grain weight ranges, but many of these are typically made for heavier or two-handed applications. Since those rods are a bit different than the norm, these guidelines are kind of necessary here. But, my thinking nowadays is why not advertise the very best grain weight window of every rod, or at least those with fast and extra-fast actions since they can be a little trickier for folks to dial in? With such a variety of fly lines on the market, it seems like there would be no downside to providing some guidance as to where a rod's sweet spot can be found.
Now, if you have a 5-weight fly rod that is rated to perform optimally with a grain weight equal to a 6-weight line, is the rod itself still truly a 5-weight rod? Ahhhhhh. The confusion never ends.......!!