I asked: "Does the rotational weight of  a spool of braided line  make it cast light lures better than monofilament?"

 

AI returned the following:

 

No, braid does not make it cast lighter lures better due to rotational weight; instead, its thinner diameter and lack of stretch allow it to cut through the air with less resistance, enabling lighter lures to cast farther than with thicker monofilament. The rotational weight is less of a factor than the line's characteristics for light lures. 

How braid helps cast light lures

• Lower diameter: 

Braided line is significantly thinner than monofilament for the same pound test, reducing wind resistance and drag during the cast. 

• Less resistance: 

A thinner line moves through the air and guides more easily, allowing a light lure to achieve greater distance. 

• No stretch: 

The lack of stretch in braid allows for a more direct transfer of energy from the rod to the lure with every cast. 

• More line on the reel: 

For the same strength, you can fit more braid on the spool than mono, which can also contribute to casting distance. 

Why the "rotational weight" argument is misleading for light lures

• Momentum: 

Light lures have very little mass, so they lack the momentum to pull line off a spool quickly, especially a baitcaster. 

• Spinning reels: 

This is why spinning reels are often recommended for casting light lures because they are better at handling the low momentum of light lures without causing backlashes, notes this Reddit thread. 

• Braid's advantage: 

Braid's thinner diameter is more important than its rotational weight in this scenario because it requires less force to get moving and maintain speed through the air.

 

The reason I asked the question goes back to my frustrations concerns with my 2017 Tatula SV TW. I'd like to give it another go to see if it's a "me" problem, fully open to the idea that it is that and hoping to unleash the magic so to speak. Maybe it just isn't a design that I find useful. . . . I'm really hoping it is in fact a "me" problem (like maybe the spool tension and mag brake settings) so I can use this reel and not feel hindered by it. 

 

I considered replacing the spool (and possibly bearings) thinking it's probably got some pig of a spool, only to learn the the spool weighs 7g at most and the replacement I found weigh in the low 6g range. The Curado BFS spool weighs 8.5g.

 

Then I weighed the stock spool when filled with monofilament: 22.9g

 

I admit to being a serial spool filler, but it got me to thinking about all the factors that make a reel cast better or worse. I was a little surprised that AI would suggest that spool weight was a much less significant contributor than line diameter and guidetrain friction if I am interpreting the response as intended.

 

If the weight of the spool isn't so significant, why do we concern ourselves with it? Or is AI billowing smoke, and not so brilliant after all?

 

This is why braid spools are BFS spools - everything is lighter and improves your top-end performance if you do it right.  

Is there any reason you need more than 30-lb breaking strength (rhetorical question)

I.

37 minutes ago, Big Hands said:

I considered replacing the spool (and possibly bearings) thinking it's probably got some pig of a spool, only to learn the the spool weighs 7g at most

I recall mine weighing something like 12.5 grams unloaded.

 

38 minutes ago, Big Hands said:

If the weight of the spool isn't so significant, why do we concern ourselves with it? Or is AI billowing smoke, and not so brilliant after all?

Whichever AI you asked is dumb.

38 minutes ago, Big Hands said:

No, braid does not make it cast lighter lures better due to rotational weight

Horse hockey.

36 minutes ago, Big Hands said:

I admit to being a serial spool filler, but it got me to thinking about all the factors that make a reel cast better or worse. I was a little surprised that AI would suggest that spool weight was a much less significant contributor than line diameter and guidetrain friction if I am interpreting the response as intended.

 

If the weight of the spool isn't so significant, why do we concern ourselves with it? Or is AI billowing smoke, and not so brilliant after all?

Your question is confusing. You didn’t ask it what the effect of overall spool weight is on casting light lures, you specifically asked it the effect of braided line’s weight. Had you asked it the question you’re inferring, like what is the effect of overall spool weight on casting light fishing lures, then you would have gotten a very different result.

 

Especially when we’re talking the low line capacities of shallow bfs spools, the overall weight difference between equal diameter braid and mono is not going to be that big. In that case, the other factors inherent to those lines will be a larger contributing factor.

4 minutes ago, PhishLI said:

I recall mine weighing something like 12.5 grams unloaded.

To me, this seems more realistic. Comparing the look of the stock spool, it's hard to believe that the aftermarket spool saves less than a gram with all that porting.

 

 

38 minutes ago, bulldog1935 said:

Is there any reason you need more than 30-lb breaking strength (rhetorical question)

 

Thank goodness this is a rhetorical question 😉

 

6 minutes ago, brophog said:

Your question is confusing. You didn’t ask it what the effect of overall spool weight is on casting light lures, you specifically asked it the effect of braided line’s weight. Had you asked it the question you’re inferring, like what is the effect of overall spool weight on casting light fishing lures, then you would have gotten a very different result.

 

Especially when we’re talking the low line capacities of shallow bfs spools, the overall weight difference between equal diameter braid and mono is not going to be that big. In that case, the other factors inherent to those lines will be a larger contributing factor.

 

Not trying to be dense here (pun intended), but are you saying that AI answered my question correctly?

 

Seems to me that it doesn't matter if the weight was from the weight of the line or the weight of the spool (other than maybe where the mass is concentrated: closer to or further from the axle of the spool). I could be wrong, and I can accept it if I am. Just trying to understand the forces at play as they truly exist.

 

At the end of the day, I am trying to maximize the casting potential of a reel that has not performed for me thus far the way I think it should have. If that means filling the spool halfway with 30 or 40 lbs braid to give me whatever advantage(s) braid might give me over monofilament, I'd like to try it before abandoning hope for this reel's place on my team.

Here how my AI (ChatGPT 5) answers the same question.  I'm showing the initial response and the final summary and leaving out several pages of physics equations and "Quantitative comparison":

 

That’s an excellent and surprisingly deep question — and yes, the rotational weight (moment of inertia) of the line on the spool does play a role in casting performance, especially with light lures. But the effect is subtle and depends on several interrelated factors.

 

Let’s break it down technically and practically:  {deleted details}

 

---

 

✅ Yes — braid improves casting of light lures primarily because it reduces the spool’s rotational inertia, making it easier to start and stop the spool.

 

But:

 

• The advantage is most pronounced with finesse weights (< 1/8 oz) and small spools (e.g., BFS reels or ultralight spinning setups).

• With normal bass tackle (¼–½ oz), the difference becomes minor compared to aerodynamics and spool tuning.

 

 

AI Misnomer - Moment of Inertia is a structural geometric property, and has nothing to do with this discussion.  

 

Rotational inertia is closer to correct - resistance of rotating mass to change

 

editorial comment - unless you filter AI with Actual I, you don't get Any I

1 minute ago, bulldog1935 said:

AI Misnomer - Moment of Inertia is a structural geometric property, and has nothing to do with this discussion.  

 

Rotational inertia is closer to correct.  

 

editorial comment - unless you filter AI with Actual I, you don't get Any I

 

I am probably using "Temu AI".

37 minutes ago, brophog said:

Your question is confusing. You didn’t ask it what the effect of overall spool weight is on casting light lures, you specifically asked it the effect of braided line’s weight. Had you asked it the question you’re inferring, like what is the effect of overall spool weight on casting light fishing lures, then you would have gotten a very different result.

 

Especially when we’re talking the low line capacities of shallow bfs spools, the overall weight difference between equal diameter braid and mono is not going to be that big. In that case, the other factors inherent to those lines will be a larger contributing factor.

 

Just for the heck of it, I asked the question more or less as you phrased it ("what is the effect of overall spool weight on casting light fishing lures"), and got much more of the answer I would have expected, so it appears that the way I phrased the question definitely affected the answer I got.

 

I had already tried several different ways of asking the question, trying to keep the difference between braid and mono as part of the premise, and maybe that is why it felt that it wasn't as significant as other factors. 

 

Apparently braid weighs about 84% of what monofilament does on a grams per cubic centimeter basis, which is much closer than I thought it would be.

AI can be useful but it depends on the data it has been trained on, the specific of the question asked, how it was asked, how the question was refined and finally the specific AI you use. There isn’t an AI out there that will answer bass fishing questions correctly all the time. Think of it more like guidelines and not absolute answers. 
 

personally, I think this forum will provide much better answers from actual experience and users and will be more direct than any AI can be right now. If it were up to me, I’d ban answers on this forum that start with “AI says…” when the user is just using ai as the source of answer only. 

19 minutes ago, bulldog1935 said:

AI Misnomer - Moment of Inertia is a structural geometric property, and has nothing to do with this discussion.  

 

Rotational inertia is closer to correct.  

Moment of inertia and rotational inertia describe the same physical concept—the resistance of a rotating object to changes in its angular motion.  You could measure the moment of inertia of a bare spool and then again with line on it; the added line would increases the moment of inertia because it adds mass farther from the axis of rotation.

As a result, more torque (or torque applied for a longer time) would be required to reach the same rotational velocity. In practice, the difference would be small but could slightly affect how easily the spool starts spinning, especially with light lures.

 

https://en.wikipedia.org/wiki/Moment_of_inertia

 

10 minutes ago, casts_by_fly said:

AI can be useful but it depends on the data it has been trained on, the specific of the question asked, how it was asked, how the question was refined and finally the specific AI you use. There isn’t an AI out there that will answer bass fishing questions correctly all the time. Think of it more like guidelines and not absolute answers. 
 

personally, I think this forum will provide much better answers from actual experience and users and will be more direct than any AI can be right now. If it were up to me, I’d ban answers on this forum that start with “AI says…” when the user is just using ai as the source of answer only. 

 

I concur 100%. 

Even Wikipedia asks to be corrected when they get it wrong.  

Inertia is resistance to change.  

Moment of inertia (second moment of area) is a geometric property.  

 

Moment of inertia applies to bending structures, such as a rod or a bridge beam, which don't rotate like a rotating mass on an axle and bearings - both rotate small increments under torsion -  something your loaded spool isn't going to do in a measurable way.  

 

1 hour ago, Big Hands said:

At the end of the day, I am trying to maximize the casting potential of a reel that has not performed for me thus far the way I think it should have. If that means filling the spool halfway with 30 or 40 lbs braid to give me whatever advantage(s) braid might give me over monofilament, I'd like to try it before abandoning hope for this reel's place on my team.

 

Let's focus on this. 

 

What is it you’re wanting to do with this reel? Is this something you’re wanting to throw 1/32oz total weight or just want it to throw 1/4oz better? What is it's desired role on this team, or are you still at the point you're just trying to find anything it does well enough?

47 minutes ago, bulldog1935 said:

Moment of inertia applies to bending structures, such as a rod or a bridge beam, which don't rotate like a rotating mass on an axle - both rotate small increments under torsion, something your loaded spool isn't going to do in a measurable way.  

The term area moment of inertia is used in structural mechanics which is what you are referring to but mass moment of inertia is used in rotation dynamics.  Type in rotational inertia in wikipedia and it will redirect you to moment of inertia for rotational dynamics.

 

 

After you get your spool mass trim, the last place to shed inertia is spool bearings.  

The heirachy improving as you go down the list:  

hybrid ceramic

unshielded hybrid ceramic

low viscosity bearing oil (you're up to about 6% cast distance improvement here)

microbearings - these come in various forms with load ranges.  

Hedgehog's load ratings fit well here 

Air Ceramic and Air HD (comparable to KTF/IXA MBS)  are good compromises between microbearings and full-size.  

10% cast distance improvement is nominal.  

You can see Air BFS isn't rated above 3/8 oz.  

More exotic are double-row bearings, such as KTF/IXA and MC-Squared.  

Casting light weights, only the inner ball row spins.  

Casting big weights and big drive loads, the outer ball row spins with big load range.  

With Air BFS bearings and double-row bearings I've measured 15% cast distance improvement.  

 

One thing's for sure - I don't think I'm clairvoyant.  

I've noticed a huge difference in control when using braid vs fluoro.  I remember skipping a reel with ease at max brake when spooled with braid and then struggling with overruns with another example of the same reel spooled with 14# Sniper.  It was like the spool was heavier and wanting to spin longer and overrun when skipping.  

Also, you're correct that line capacity has a huge impact on spool weight.  Spools meant for light weight baits are shallow to keep the line capacity and weight down.  You can also under fill your spool to reduce the weight of the line on the spool and effectively make the spool start up faster and behave like a smaller diameter spool.  Daiwa puts a line on their SV spools that indicates roughly the 30mm mark.  Its visible on the side of the spool.  This is meant to be used as an alternative filling level on the spool to help them start up better and work better with lighter weight baits.  I remember when they 1st came out in Japan.  They would show off this feature in videos.  They later made reels with small 30mm spools from the factory.

39 minutes ago, Bigbox99 said:

I've noticed a huge difference in control when using braid vs fluoro.  I remember skipping a reel with ease at max brake when spooled with braid and then struggling with overruns with another example of the same reel spooled with 14# Sniper.  It was like the spool was heavier and wanting to spin longer and overrun when skipping.  

 

This won’t be the mass, rather the springiness of the fluorocarbon line.  I learned this one earlier this year.  Because the fluoro is springy, it helps the spool to unwind and requires a touch more tension or braking to hold it back.  I normally run zero spool tension on everything, but my fluoro reels I have to add a bit back for control.  

Will there be a test?

The test is catching fish on the far channel slope.  

 

4 hours ago, Big Hands said:

I asked: "Does the rotational weight of  a spool of braided line  make it cast light lures better than monofilament?"

 

AI returned the following:

 

No, braid does not make it cast lighter lures better due to rotational weight; instead, its thinner diameter and lack of stretch allow it to cut through the air with less resistance, enabling lighter lures to cast farther than with thicker monofilament. The rotational weight is less of a factor than the line's characteristics for light lures. 

How braid helps cast light lures

• Lower diameter: 

Braided line is significantly thinner than monofilament for the same pound test, reducing wind resistance and drag during the cast. 

• Less resistance: 

A thinner line moves through the air and guides more easily, allowing a light lure to achieve greater distance. 

• No stretch: 

The lack of stretch in braid allows for a more direct transfer of energy from the rod to the lure with every cast. 

• More line on the reel: 

For the same strength, you can fit more braid on the spool than mono, which can also contribute to casting distance. 

Why the "rotational weight" argument is misleading for light lures

• Momentum: 

Light lures have very little mass, so they lack the momentum to pull line off a spool quickly, especially a baitcaster. 

• Spinning reels: 

This is why spinning reels are often recommended for casting light lures because they are better at handling the low momentum of light lures without causing backlashes, notes this Reddit thread. 

• Braid's advantage: 

Braid's thinner diameter is more important than its rotational weight in this scenario because it requires less force to get moving and maintain speed through the air.

 

The reason I asked the question goes back to my frustrations concerns with my 2017 Tatula SV TW. I'd like to give it another go to see if it's a "me" problem, fully open to the idea that it is that and hoping to unleash the magic so to speak. Maybe it just isn't a design that I find useful. . . . I'm really hoping it is in fact a "me" problem (like maybe the spool tension and mag brake settings) so I can use this reel and not feel hindered by it. 

 

I considered replacing the spool (and possibly bearings) thinking it's probably got some pig of a spool, only to learn the the spool weighs 7g at most and the replacement I found weigh in the low 6g range. The Curado BFS spool weighs 8.5g.

 

Then I weighed the stock spool when filled with monofilament: 22.9g

 

I admit to being a serial spool filler, but it got me to thinking about all the factors that make a reel cast better or worse. I was a little surprised that AI would suggest that spool weight was a much less significant contributor than line diameter and guidetrain friction if I am interpreting the response as intended.

 

If the weight of the spool isn't so significant, why do we concern ourselves with it? Or is AI billowing smoke, and not so brilliant after all?

 

You should re-weigh that spool empty, I’d be shocked if that reel spool weighs only 7 grams. 

36 minutes ago, bulldog1935 said:

The test is catching fish on the far channel slope.  

 

Nice! Very nice response. 🇺🇸🇺🇸🇺🇸

4 hours ago, brophog said:

 

 

Let's focus on this. 

 

What is it you’re wanting to do with this reel? Is this something you’re wanting to throw 1/32oz total weight or just want it to throw 1/4oz better? What is it's desired role on this team, or are you still at the point you're just trying to find anything it does well enough?

 

Great question. I have three "BFS" reels for the tiny stuff, which is 1/16th oz and heavier. I have a Curado BFS for stuff just above the three BFS reels I have. I keep reading that this platform is great for throwing lighter (not BFS light) baits, and I have tried it for just about everything. I'd be very pleased with 1/4 oz or heavier AND just trying to find something it does well. If it lent itself well to skipping, that'd be a bonus as it is something I currently have neither the skill nor gear (that I know of) to do that. If it can't compete with a Fuego CT somewhere, I'll just try to find it a new home and move on. It's too nice not to have a purpose.

3 hours ago, bulldog1935 said:

After you get your spool mass trim, the last place to shed inertia is spool bearings.  

The heirachy improving as you go down the list:  

hybrid ceramic

unshielded hybrid ceramic

low viscosity bearing oil (you're up to about 6% cast distance improvement here)

microbearings - these come in various forms with load ranges.  

Hedgehog's load ratings fit well here 

Air Ceramic and Air HD (comparable to KTF/IXA MBS)  are good compromises between microbearings and full-size.  

10% cast distance improvement is nominal.  

You can see Air BFS isn't rated above 3/8 oz.  

More exotic are double-row bearings, such as KTF/IXA and MC-Squared.  

Casting light weights, only the inner ball row spins.  

Casting big weights and big drive loads, the outer ball row spins with big load range.  

With Air BFS bearings and double-row bearings I've measured 15% cast distance improvement.  

 

One thing's for sure - I don't think I'm clairvoyant.  

 

I'd thank this twice if I could.

1 hour ago, F14A-B said:

You should re-weigh that spool empty, I’d be shocked if that reel spool weighs only 7 grams. 

 

TBH, I will be too, and I intend to do just that. Soon.

6 hours ago, Bigbox99 said:

Also, you're correct that line capacity has a huge impact on spool weight.  Spools meant for light weight baits are shallow to keep the line capacity and weight down.  You can also under fill your spool to reduce the weight of the line on the spool and effectively make the spool start up faster and behave like a smaller diameter spool.  Daiwa puts a line on their SV spools that indicates roughly the 30mm mark.  Its visible on the side of the spool.  This is meant to be used as an alternative filling level on the spool to help them start up better and work better with lighter weight baits.  I remember when they 1st came out in Japan.  They would show off this feature in videos.  They later made reels with small 30mm spools from the factory.

So, I removed the monofilament down to the line and the monofilament that I removed weighed 5g 😮