Why Do Fishing Rods Bend? How Rod Bending Increases Yield

One of the toughest decisions to make when starting out is selecting the size of rod to use. Both the length and the construction material will have a direct impact on the rod’s “Action.” Simply put, the desired amount of bend in the rod should be considered. So, why do fishing rods bend?

The “Bend” of the rod is an important factor when selecting a rod. Bending creates inertia when casting a lure, bait, or fly. It also takes pressure off your line, knots, and hook when fighting a fish. Not enough bend can create tension and result in either lost fish or equipment failure.

So now that we understand the need to have fishing rods bend, let’s talk about each of these in more depth to help you select the right rod for different applications.

Choosing the Right Rod Size

Size Matters

One of the biggest mistakes I see beginners make is not having the correct size rod for the intended application. Commonly, rookies tend to select a rod that is too big.

While a bigger rod does help you land larger fish, it also limits you in quite a few ways. The bigger the rod, the harder it is to cast smaller baits. This is because bigger rods tend to be stiffer, to allow you to put more pressure on bigger fish. Tie a string to a broomstick with a small lure and try to cast it. You will quickly understand this concept. Larger rods also tend to have less feel, making it harder to feel subtle bites. 


The bend of the rod allows you to create a whipping motion that carries your cast further. This type of bend, called “Load ,also allows you to place the bait/lure more accurately. Conversely, a rod that is too bendy or light can make it harder to cast larger baits and put the needed pressure on larger fish.

Weight and Stiffness 

Fishing rod sizes are categorized in two ways, weight and stiffness. The weight is measured in line size and given in pounds. The stiffness is measured in a range from Light to Heavy.

Fishing Line Size Considerations

Line size refers to pound test of a line. This is the breakage point of the line when stretched to its max.

For example, 10lb test, will allow you to put 10lbs of pressure on a fish before the line snaps. Line sizes can range from 4lbs – 150lbs and used to catch anything from small trout to 800lb marlin!

It is typically best to use as light of line as you can to catch the intended fish. The smaller the line, the less the fish will see it, and the easier the line will cast. Things such as fishing around trees, bridges, or other structure should be considered when selecting a line. The line’s pound test does not take into account abrasion or being cut by structure. 

Finding Line Size Compatibility on Your Rod

When looking at the markings on a fishing rod, you will see the suggested line size given. The figure is given in a range and will sometimes include the size of a lead/lure weight to be applied. If a lead/lure weight figure is given, it will be given in ounces.

The line size range allows you to get a feeling for what size fish the rod is intended to catch. A larger diameter rod will have a greater line size and will withstand greater amounts of pressure. Freshwater or inshore saltwater rods tend to fall in a range of 8-17lb line size, where offshore saltwater rods range from 20-80lb or higher.

Line size does not always correlate to the stiffness of the rod, whereas a line size of 30-50lbs can still be quite “bendy”.

How Bend is Measured

The maximum amount of pressure applied to a fish is when there is absolutely no bend in the rod. When fighting a fish, if you point the rod directly at the fish, you are allowing the fishing reel and the amount of reel drag to fight the fish. In most circumstances this is too much pressure. Therefore, the rod is designed to reduce the pressure by having bend. 

The amount of bend within a rod is measured in a scale from Light to Extra Heavy. The amount of this bend is called the “Action” of the rod.

Lighter Rods

A “lighter” rod will have more bend and feel like a pool noodle with shaken. Lighter rods are also referred to as slow or soft.

When casting a light rod, the fishing rods bend is more exaggerated causing the casting motion to take longer, hence being called slow. The smaller and more flexible tip will allow you to feel more subtle bites on the line.

Light rods are great when fishing for species who tend to steal baits off the hook rather than aggressively strike. Also because of the added bend, smaller baits can be casted to further distances as the rod bend creates more forward inertia.

Heavy Rods 

On the opposite side of the spectrum is a “heavy” rod. With little to no bend, this causes the rod to be stiffer and the casting motion faster. As you can guess, these rods are referred to as “fast.”

Heavy rods are ideal for less casting distance or throwing larger heavier baits/lures. The stiffer rod allows more pressure to be applied to the fish and is needed when fishing for species that need to be landed quickly. 

Most heavy rods are not designed to be casted, but rather dropped straight down. These are rods for bottom fishing on offshore reefs or trolling a lure behind the boat.

Medium Rods

Somewhere in the middle are medium rods. Some of the most common rod selections are within the medium range. This will allow adequate bend for casting and feel, but still have backbone to handle larger fish.

If only one rod could be chosen, it is ideal to go with a medium action rod.

Action Blends

In addition to actions mentioned above, there can be blends of stiffness. The scale includes actions such as medium-light, medium-heavy, and extra heavy. As you can see this will give an option that is ideal for almost any application. See illustration below. 

Applying the Concepts

Now that we understand what components make up selecting a rod, let’s put it all together. 

Different types of fishing are going to require different rod sizes 

If I am a bass fisherman that likes to throw top water lures or artificial worms, an ideal rod may be a Medium rod in the 8-14lb line range. This rod would allow me to have feel when retrieving my lure, but lined to the size of the fish I am catching.

On the flip side of the spectrum, if I am an offshore reef fisherman, I would probably select a Heavy action rod in the 40-80lb line range.

Example of Rod Markings

Let’s take a look at how the information will appear on a rod. For example, if we look at the markings on the rod below, you will see the line size designation of 8-14Lb’s. This would indicate that the rod is designed to handle 8-14lb pound.

In this example, the lead/lure weight is also given. The rod is rated to throw 1/8-1/2 oz weights or lures. Additionally we can see the “Action” of this rod is Medium–Light, making it an ideal rod for throwing small lures or baits to smaller size fish.


Fly-fishing Rods

Fly-fishing rods have similar characteristics to traditional fishing rods, but use slightly different terminology. In this case, because in fly-fishing we are strictly using the weight of the line to propel a weightless fly forward, the rods will correspond directly to the size of the line.


Fly lines are classified by “Weights”. These weights can range from size 2 for very small stream fish, to size 14 for large gamefish such as tarpon or sailfish. The higher the weight, the thicker the diameter of the line and greater strength. 

The rod is chosen by the corresponding fly line weights. Fly rods also range from 2 weight to 14 weight and the stoutness of the rod corresponds to this weight. The smaller the weight of the rod, the more bend and feel the rod will have. The larger the weight of the rod, the stiffer the rod will be become. The most common size fly rod is the 8 weight. The middle of the road 8wt will generally catch you most species and has become the most popular rod sold.


Like traditional fishing rods, fly rods also have different types of action. However, the action varies by the manufacturer of the rod and the material it is made of. Fly rods do not have a stated action listed on the rod. Instead, the action is determined by throwing the rod and is typically referred to as fast, slow instead of light, or heavy. For experienced fly casters, faster rods are preferred and typical cost a premium to purchase.


There are a number of factors to consider when selecting a fishing rod. Understanding why fishing rods bend leads to better rod selection. Depending on your application, the amount that fishing rods bend can make or break your experience. If only a single rod can be selected, a bend in the medium action range rod should do the trick!