We are going to air out some not-too-dirty laundry about the fishing line business as part of a marketing lesson for our customers...because we feel it is important information and you guys ought to know it if you don't already.
And the reason why we decided to clarify the subject is because we thought it would be better to put your interests first, to make sure you are as successful as you can be on the water.
Every company has different LB tests with different line diameters than everyone else. Sometimes it is very legitimate....a line that maybe is considerably smaller in diameter than others, actually breaks quite a bit higher then comparable diameters. That's fine, that is a good thing.
For a point of reference, we would like to share a conversation we had with a customer recently at a tradeshow, he was upset that there was no consistency across line manufacturers with regards to line diameter and breaking strength. I laughed, then apologized, and then asked him a few questions. Is there consistency for large pizza's around the world with regards to actual dimensional size, price, and amount of toppings? Is there consistency for pickup trucks for horsepower and bed size? Is there consistency for banks around the world with regards to how many of what type of transaction fee's they charge? He laughed back and acknowledged the obvious....every company of any industry defines itself by the uniqueness of it's product and services....why would they want to be the same as everyone else? We then went on to discuss IGFA rated fishing lines which are appropriate if you are looking to break or set records, and feel like paying a premium price for a line manufactured to those standards. IGFA rated lines are the only option for any type of "consistency", at least as far as breaking strength goes.
Where it gets confusing for you is trying products across different manufacturers, and individual product lines within those manufacturers. You try lot's of different pizza parlors until you find the one's you like the best, depending on your mood, which might change frequently....you can do the exact same thing with fishing line.
So let's get down to the basics and unwind this whole topic and send you back out onto the water with maybe a bit more information than you had before you got here. We feel this is important because we see alot of guys purchasing the wrong sized product of ours for a certain type of fishing, and we want to make sure everyone understands what and why they should be focusing on...rather than just a number on the package.
Breaking strength. If you grabbed a piece of fishing line and wrapped it a number of times around each of your fists and pulled apart as hard as you could, the amount of pressure it took to break that line measured in LB's would be a lines "breaking strength". This is most often what is being referred to on the label of a package of line, but it is probably fudged a little bit to the high side just to keep you safe.
Knot strength. Knot strength is ALWAYS less than breaking strength. Depending on the material type (mono vs fluoro, etc) and the knot used, that will dictate your knot strength. At the end of the day, this is the number that really matters as it is the true weak link in your entire operation. Fluorocarbon material in general has a tendency to break in the 80% of breaking strength range all the way down to the low 60% range depending on the quality of material and knot selected. Monofilament knots can break in the 80-90% range of breaking strength depending on the knot. So....most line manufacturers will factor in knot strength numbers and use the "best" performing knot and put that on their package, rather than the line (no knot) breaking strength. So they are guessing as to what knot you should/might be using in order to put forth the "best" but probably not actual numbers.
LB test. Already discussed, the measurement of pressure in LBs that is required to break a piece of line not including the knot.
Diameter. One of the most important variables for a couple of reasons, and first is performance. Sometimes a smaller diameter line will work better than a larger diameter line in certain situations. Smaller is not always better! Sometimes small is too small, and the line becomes easily impacted by currents, the wind, whip of the rod tip, etc..and you are going past the point of diminishing return. Super small braids in particular can cut and underwrap on your reel, embedding itself into a miserable mess, particularly if you spooled it under low or no tension. Larger diameter is sometimes better...not just because it MIGHT be stronger. Sometimes, larger diameter is better simply to give you more material to work with should you drag your gear across structure that might cut the line. The more material (diameter) the more significant the abrasion or cut could be prior to the line breaking. We don't care how abrasion resistant your small diameter line is...you are working with less material to begin with and are living on the edge in some situations. Larger material might allow you to use a different (and possibly better) set of knots as well.
Before selecting a line, or moving between different line manufacturers, read the label. Not just the rated LB test (breaking strength). Read the label, understand the material or mixture of materials, and read the diameter. Then compare it to what you have been using, or another similar sized line and try to get some perspective on what you are actually looking at. Example, a 20lb test could vary significantly in diameter, so what are you actually going to experience from a performance perspective? A fat 20lb line with a larger diameter could work against you in a heavy current vertical jigging situation, and conversely, a super skinny small diameter line could work against you in a casting situation with strong winds or a soft tipped rod.
How about a manufacturers known reputation for over or under stating their breaking strengths? Not that this is a bad thing, but you have to be aware of whether you are really fishing with an 8lb line that breaks AT 8lbs, or are you looking at a line that says 8lb on the label but in reality breaks at 12lb? This is particularly critical in any situation where you "leader down" to your fish. You ALWAYS want your leader to break before your mainline. If you are using a super fantastic wicked strong grossly under-rated leader material from your favorite line company, and match it up with an over-stated or correctly stated breaking strength mainline, guess which might break first? Do you really want your mainline to break off a hundred yards into your linecounter or centerpin because your super fantastic strong leader would not break first? You just shut yourself down for the day with a severely depleted supply of mainline on your reel.
And on the breaking strength train of thought, just because you think you might hook into a 20lb fish does not mean you need a 20lb fishing line. Guys catch sailfish on 2lb test, and bass guys fish with 60lb braid....so what does that tell you?
Never in any scenario should you be in a dead stop situation where the fish or you are completely stationary and unmoveable (unless you are fishing for Grouper). You have a drag, the fish is moving, you should never be in a situation where you ever get remotely close to whatever the actual breaking strength of your line should be.. If you feel you are pushing the line close to its breaking strength (or your knot strength) then back off the drag and let the fish run.
Don't forget to factor in the shock absorption of your fishing rod which can help offset initial bursts or runs by fish without allowing your line or knot to get close to it's breaking capacity.