Choosing A Fly Rod Size - Start With The Line (1 of 15)
Fly line sizes determine how far you can cast, what type and size of fly you can throw, and what kind of fish you can land with that rod. The same fly line that will throw this great big heavy streamer, with a weighted head on it, is not the same fly line that's going to deliver this little tiny dry fly with delicacy. The one that throws this bigger fly is going to be thicker and heavier than the one that throws this little tiny dry fly. I can show you two different rods. I have a 4-weight here in my hands, which would be typical for a trout stream like this, and I have another rod here: a 9-weight, which would be your basic saltwater rod. Even from quite a distance, you can see that the line is thicker on the 9-weight rod and also the rod is much thicker. This rod has a lot more beef and a lot more guts. It can hold this heavy line in the air a lot better than this 4-weight. This 4-weight can't hold that 9-weight in the air at all. In fact, you might even break the 4-weight if you cast a long cast with this 9-weight. So, two different weights, the 4-weight has the delicacy to throw a trout fly and the 9-weight has the power to throw a big saltwater or salmon or a bass fly without collapsing.