Understanding Baitcasting Reels: Adjusting the Tension and Brake System To Avoid Backlashes

If you're tired of untangling the bird's nest left when your baitcaster backlashes, then it's time you learn how to properly set up and tune a baitcasting reel to avoid it. In this guide we'll go over everything you need to know to prevent a baitcaster from backlashing so you can enjoy your time spent fishing instead of picking out a tangled mess in your reel.

There's nothing more frustrating than dealing with a backlashes while fishing. But, picking out a rats nest after making a bad cast is something we've all done and still do occasionally. Even professional bass fishermen backlash from time to time too. Thankfully backlashes and overruns can be almost entirely eliminated by fine tuning your baitcaster's settings and learning to use your thumb.

Just remember next time it happens, that backlashes happen to the best of us. It's sort of just part of the deal when using a baitcaster, and by understanding what's causing them in the first place you'll gain control over how often they occur and mostly eliminate them forever. Stay calm, make adjustments to the reel, and keep on fishin'!

Bad backlash on a baitcaster reel.

What Is Backlash And Why It Happens

The primary reason for a backlash is slack in the fishing line while the reel's spool continues to spin. This is also known as overrun. The lure is what should pull the line off the spool.

Backlashes occur when the reel's spool rotates faster than the weight of the lure can peel the fishing line from the spool. If the spool continues spinning when the lure stops or slows, it causes overrun and the line “fluffs” up on the spool. If the line fluffs off the spool far enough, loops form and get caught around each other, knotting up, and putting a sudden stop to your cast.

Backlash Theory

To help illustrate how backlashes occur and also explain why baitcasters have breaks and a spool tension system, you can take a piece of string, spaghetti noodle, or even a chunk of fishing line and lay it on a table.

Try pushing one end of the string to move it in a straight line and see what happens. It bunches up, right? This is what's happening when the spool overruns and gets ahead of the line coming off it. The other end of the line (the end the lure would be attached to) isn't moving out of the way, so it gets bunched up inside the reel.

Now pull one end of the string while pushing the other. The string moves in a straight path, right? This is what happens when the brakes and lure are tuned and working together. The brakes slow the spool just enough to keep tension in the line as the lure pulls it out of the reel and out of the way.

Now, pull one end of the string a short distance forward in a jerking motion. The string moves forward, but the abrupt stop causes the string to bunch up. This is what happens when the brakes don't slow the spool quick enough when the lure slows or stops. Beginners who haven't learned to use their thumb and tune their baitcaster often have problems with backlashing at the end of their cast as the lure touches the water. It's because the spool keeps spinning when the lure stops!

Scenarios Where Baitcaster's Backlash And How To Prevent It

There are a few primary scenarios where beginners struggle with backlashing and most of them are simply the result of not understanding the basics of how a baitcaster works. To overcome this, it's important to understand the basic components of a baitcaster and what each part is designed to do. You can view a comprehensive breakdown of baitcasters here.

I've watched anglers use baitcasters who didn't know the difference between the spool tension knob and brake system and when to use which. I watched as they backlashed cast after cast, got frustrated, screamed profanities, and eventually gave up for the day. Don't be that guy! Stop, chill for a second, and take a moment to think through and understand why backlashes occur in the first place so you can make adjustments and continue enjoying your time bass fishing instead.

Understanding The Variables You Can Adjust To Prevent Backlash

Below is a breakdown of the primary variables that can be adjusted to prevent your baitcaster from backlashing on you.

Spool Tension Knob

The tension knob on baitcasters can be located on the same side as the reel's handle. On the underside of the spool tensioning cap there is a small piece of material that, when tightened, is pressed against the end of the spool's spindle.

Image of a baitcaster spool tensioning knob how it works showing the material that is pressed against the end of the spool's spindle shaft.

Imagine using a power drill. As you push the tip of the spinning drill bit against the wood, the applied pressure causes friction, slowing the bit's rotation. With too much pressure it will seize and stop rotating completely. Try cranking down your tension knob and opening the bail by pressing the button. The lure shouldn't move at all.

Thus, tightening your baitcaster's tension knob down will apply more pressure to the end of the spindle, eventually preventing the spool from moving by the weight of the lure alone. Loosen the knob all the way and little to no resistance is applied to the spool's spindle. Your lure should plummet to the ground.

As a general starting point for adjusting your spool tension, loosen the spool tension knob until you can feel some side to side slop in the spool. Then begin tightening the tension knob. When the side to side movement disappears, stop tightening. This is a great place to start dialing in and fine tuning the spool's tension system. You should be able to release the lure and the spool shouldn't overrun when the lure falls to the ground.

Brake System

There are 2 primary types of brake systems manufacturers use: magnetic and centrifugal brakes. Some baitcasters have one braking system while others contain both.

Where the tension knob is a constant pressure that's applied to the end of the spool's spindle, a baitcaster's brake system doesn't create resistance until the spool begins turning. Magnetic brakes create magnetic fields and centrifugal brakes work by throwing little brake pads outwards as the spool spins (think of the Gravitron carnival ride).

Typically magnetic breaks can be adjusted by an external dial opposite the reel's handle, while the centrifugal brakes require you to pop off the side plate. A good starting point is to set everything to the middle.

Lure Weight

When changing lures, the brake and tension settings may need to be adjusted if the weight of the new lure is significantly different from the previous one. Just because you were casting the previous lure just fine, doesn't mean your settings are correct for the new lure too.

If you've adjusted the settings for a lighter lure, and are still struggling with backlashes, the lure may be too light for your baitcaster and you may want to look into using a finesse rod and reel setup in this scenario.

Fishing Line

Some fishing line materials are more prone to line memory than others. Line memory is where the fishing line maintains the shape of the spool and can play a big role in backlashes. If your line has lots of memory and is already trying to jump off the spool when there is no tension in the line, then you'll be more prone to backlashing. You can tell how much memory your line has by how much it curls up when there is slack in the line.

An image showing line memory. Fishing rod with curled fishing line from spool line memory.

Mono, fluorocarbon, and copolymer fishing lines are prone to line memory. The longer these fishing line materials sit on the spool, the more prominent their memory becomes. This isn't to say you shouldn't use them, they definitely have their place, but they require more attention from your thumb when casting than braided fishing line. Before changing lines though, rule out the other variables as the potential problem candidate. Also note that some brands of fishing line are worse than others about this. If you've determined the line is your cause for backlashing, you may want to try using another brand.

Casting Power

How you cast has a major effect on backlash. If you're trying to bomb a cast across the lake, the force created can cause a whipping motion at the tip of your rod, causing the bait to halt for a split second before it's launched across the pond. This can be enough time for the spool to get ahead of the fishing line and thus backlash.

The whipping motion caused by a hail mary cast to the moon will cause one of three things to happen:

The brakes can't keep up - The initial force from a powerful cast can cause the lure pulling the fishing line off the reel to create a burst of speed that overpowers the brake system. By the time the brakes finally catch up, there is already a backlash forming from the spool spinning faster than the line leaving it.

Think of spinning a bicycle tire while holding the brakes. If you use enough force, you will overpower the brakes and the tire will spin. The same can happen to your reel. When you put too much power into a cast the brake system can't keep up and the spool will spin faster than the line can leave the reel.

The lure hangs in the air - Oftentimes, the release point on a power cast is too far back that the lure moves in an arching path, causing it to hang in the air for just a second. That brief moment the lure stalls mid-air is enough time for the spool to get ahead of the fishing line and cause a backlash. A little arch in the cast is okay, but make sure it doesn't get hang time. If you need to cast hard, make sure to use thumb control to tame the spool.

The lure crash lands into the water - When you're making a power cast and release too late, you may not arch your lure, but instead launch the lure like a bullet speeding straight toward the water's surface, stopping it in its tracks. If the spool is left spinning freely, the line will overrun and create a mess. Note that the same will also happen if your lure hits any solid object. This could be as simple as a leaf that slows the lure just enough to allow for overrun. Don't ask me how I know.


Casting into a strong wind can slow the velocity of the lure enough that it's moving slower than your spool is rotating. Try changing the direction you cast from, or turning up the brakes to slow the spool down faster.

If your brakes are maxed out and you still need to cast into the wind, you'll just have to accept that you won't be able to cast as far and may need to just move spots. Trying to power cast harder into the wind is going to result in a bird's nest. Try to position yourself so you are casting with the wind when possible, or at least across it.


Your thumb is perhaps the most important braking system of all! If you're casting and giving everyone a thumbs up around you, you're doing it wrong. Ask any professional or seasoned bass fisherman how to use a baitcaster and they'll likely tell you it's all about mastering thumb control.

Learning to feather the spool with your thumb to control the speed it spins during a cast is vital to becoming proficient with a baitcaster. By keeping your thumb on the spool of line as you cast, you'll be able to tell if the line is “fluffing” off the spool. When this happens, gently feathering the spool with your thumb will slow the spool and allow the line to catch up with the speed of the spool and correct itself, preventing you from backlashing.

When To Adjust Spool Tension Knob vs. Brake System

Learning to tune a baitcaster is a crucial skill all beginner bass anglers should learn for an enjoyable fishing experience. If you've already gone through the steps to set up your baitcaster and are finding you still occasionally backlash, then you'll need to fine-tune your reel to eliminate it. To do this, you need to know when to adjust the spool tension knob and when to adjust the brakes.

Most backlashes occur in one of 3 places: the beginning of a cast, middle of a cast, or at the end as the lure touches the water's surface.

When to adjust the spool tension or brakes on a baitcaster.
  • Backlashing at the start of a cast? You're likely overpowering the braking system. If you're putting a lot of power into a cast it's likely the baitcasters brakes won't keep up. A heavy lure will also create more force when cast. The combination of the lure's weight and your casting power is too much for the brakes. To fix this, you can:
    • Increase the brakes if they aren't already maxed out.
    • Add extra braking power by feathering the spool with your thumb.
    • Decrease the amount of power behind your cast.
    • Use a lighter lure.
  • Backlashing mid cast? The spool is likely moving faster than the lure can peel the line off the spool. Because the fishing line isn't leaving the spool fast enough, it's overrunning the spool and knotting up. This is usually because the lure is momentarily slowing mid air during an arching cast, or the brakes are just too loose. To fix this, you can:
    • Increase the brakes if they aren't already maxed out.
    • Avoid arching the lure when casting.
    • Feather the spool with your thumb.
  • Backlashing at the end? Backlashing at the end is usually the result of the lure slowing as it touches the water's surface. Because the lure's momentum is suddenly halted, if the spool doesn't also stop then you'll experience overrun, and a potential birdsnest. To fix this, you can:
    • Increase the spool tension by tightening the tensioning knob.
    • Slow or stop the lure with your thumb.


Preventing backlashes when using a baitcaster is a crucial skill all bass anglers should learn. By understanding the basics of how a baitcaster works, and the different variables that can be adjusted, you can fine tune your reel to avoid backlashing. If you're backlashing towards the beginning or middle, you likely need to adjust the baitcasters brakes, while an overrun at the end of a cast is typically resolved by tightening the reel's spool tension.