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Angry John

Rod Torque A Bass Issue

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Not wanting to hijack the spiral thread, is rod torque really an issue with bass rods. I could imagine on swimbait rods it might be a factor but normal rods???

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Rod torque is a factor whenever a casting Rod is loaded. Obviously the heavier the load the more of a factor it is. All things are relative, guide size for instance, weight for another. Spiral wrapping also proves line flow, but again the degree can be argued. Spiral wrapping done properly is not a gimmick nor is it a cure all.

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How does rod torque change as rod power and action decrease? Aside from the rod wanting to twist in your hand, does the tip end of the rod twist relative to the grip...?

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In my book, the longer the backbone, the greater the torque.  Generally speaking, the faster tapered rods will transition to backbone sooner than more moderate tapered rods meaning that faster tapers have more torque assuming a fixed rod length, because obviously longer rods offer more torque (aka leverage) than shorter rods.  I've owned more than one broom handle moderate and willow branch Xfast so there's no replacement for getting hands on a blank before you buy.  I'd be getting hands on a blank or at the very least taking word of mouth from a reliable source. 

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I won't claim to be an expert on physics, but in my mind I feel that rotational torque would be more noticeable in a longer rod with more guides pulled by the line. I wouldn't expect action to play much of a role as we don't fish on just one plane. 

 

The tip can't twist relative to the grip as the blank is one piece and the guides distribute stress along the entire length.

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also consider building on the spline of the rod vs the straight edge. 

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The short answer to your question is "NO."  It's really not an issue under most circumstances.  But since us engineering nerds don't particularly like short answers,

 

The physics work something like this...

 

A rotational force is primarily focused at the point the load changes direction.  Meaning, the tip top takes most of the force of the line load.  There is very little load on the rest of the guides however the force is transferred down the blank to the grip where it is anchored, by your hand.  The break occurs at the weakest point, normally in the first few inches from the tip.

 

That being said I have only broken two or maybe three rods in my lifetime from what I think was rotational force.  Most breaks are from weak and damaged spots on your blank caused by car doors, rod lockers and such.

 

As a rod builder rotational force is not the only reason I have started acid wrapping.  I'm convinced I gain casting distance and eliminate line wrap at the tip top.  Plus they look good and since you can't buy them at BPS, they are clearly identified as a "custom rod."

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I won't claim to be an expert on physics, but in my mind I feel that rotational torque would be more noticeable in a longer rod with more guides pulled by the line. I wouldn't expect action to play much of a role as we don't fish on just one plane. 

 

The tip can't twist relative to the grip as the blank is one piece and the guides distribute stress along the entire length.

 

 

The short answer to your question is "NO."  It's really not an issue under most circumstances.  But since us engineering nerds don't particularly like short answers,

 

The physics work something like this...

 

A rotational force is primarily focused at the point the load changes direction.  Meaning, the tip top takes most of the force of the line load.  There is very little load on the rest of the guides however the force is transferred down the blank to the grip where it is anchored, by your hand.  The break occurs at the weakest point, normally in the first few inches from the tip.

 

That being said I have only broken two or maybe three rods in my lifetime from what I think was rotational force.  Most breaks are from weak and damaged spots on your blank caused by car doors, rod lockers and such.

 

As a rod builder rotational force is not the only reason I have started acid wrapping.  I'm convinced I gain casting distance and eliminate line wrap at the tip top.  Plus they look good and since you can't buy them at BPS, they are clearly identified as a "custom rod."

 

DVT: As wall thickness and blank diameter decrease, the force required to twist the tip of the rod away from neutral (guides and tip top all in line) decreases making it easier to twist, won't it...? My thinking is that with lighter powered rods that get into their backbone slower, this would be that much more evident. I have nothing aside from a hunch to back this train of thought up...

 

FishinDaddy: I'm worried less about breakage and more about the actual science/art behind rod building. Thank you for the explanation!

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How does rod torque change as rod power and action decrease? Aside from the rod wanting to twist in your hand, does the tip end of the rod twist relative to the grip...?

Yes, the tip section of the rod will twist. The lighter the power, the more it will twist under a load.

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Yes, the tip section of the rod will twist. The lighter the power, the more it will twist under a load.

 

Would lighter powered rods then lend themselves that much more to a spiral wrap? I started thinking about this when I was looking into a ML baitcasting rod and also saw Tom Kirkman's demonstration of a spiral wrap vs a traditional guides-on-top rod when loaded. To take it a step further, would an extra guide or two out towards the tip help to minimize this tendency? I realize adding a guide or two is counter to the logic of a simple spiral and being able to delete a guide or even two, but if it helped overall rod function...?

 

@ Angry John: sorry about the irony of me hijacking your thread that was started with the intent of not hijacking another...

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One thing I have found is that you won't notice how much the torque affects you until you try a spiral wrapped rod. Makes a world of difference. So yes, torque is there.

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Well I am going to test this for myself as DVT is going to wrap me a spiral.

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Adam, any conventionally wrapped casting rod will twist under a load. It's just more noticeable in lighter powers.  The load pulling the tip down, then to the side, and ultimately to the bottom, is the reason for the twist. I don't see how adding more guides would negate this effect, although I could be missing something.

 

Test this some time. Tie your line off to something solid, back off about thirty feet and start putting a bend in your rod. If you want to see this very easily, use an ultra-light spinning rod turned upside down. Put a bend in the UL rod with the reel on top. It won't take much force until you see the tip guide at 180 degrees around from the stripper guide. It will take more force with a medium power casting rod, and even more with a heavy.

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The short answer to your question is "NO."  It's really not an issue under most circumstances.  But since us engineering nerds don't particularly like short answers,

 

The physics work something like this...

 

A rotational force is primarily focused at the point the load changes direction.  Meaning, the tip top takes most of the force of the line load.  There is very little load on the rest of the guides however the force is transferred down the blank to the grip where it is anchored, by your hand.  The break occurs at the weakest point, normally in the first few inches from the tip.

 

That being said I have only broken two or maybe three rods in my lifetime from what I think was rotational force.  Most breaks are from weak and damaged spots on your blank caused by car doors, rod lockers and such.

 

As a rod builder rotational force is not the only reason I have started acid wrapping.  I'm convinced I gain casting distance and eliminate line wrap at the tip top.  Plus they look good and since you can't buy them at BPS, they are clearly identified as a "custom rod."

 

Great insight.

I've got a rainshadow blank here I've been on the fence about spiral wrapping and you just pushed me over the edge.  

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Adam, any conventionally wrapped casting rod will twist under a load. It's just more noticeable in lighter powers.  The load pulling the tip down, then to the side, and ultimately to the bottom, is the reason for the twist. I don't see how adding more guides would negate this effect, although I could be missing something.

 

Test this some time. Tie your line off to something solid, back off about thirty feet and start putting a bend in your rod. If you want to see this very easily, use an ultra-light spinning rod turned upside down. Put a bend in the UL rod with the reel on top. It won't take much force until you see the tip guide at 180 degrees around from the stripper guide. It will take more force with a medium power casting rod, and even more with a heavy.

 

My (likely flawed) thinking was that with more guides for the line to torque against, that would engage more of the blank and in turn create more resistive force against the torque trying to twist the rod. Does all of the torque force originate at the tip top?

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The guides distribute the stress of any load along the length. adding and subtracting guides affect how much stress there is at a given point but not the overall load. The fewest guides you can use to accomplish the task, the better as the saved weight results in improved responsiveness.

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Is taught isctf...

Inside curve to fish

In other words spline your rod and put the soft side to the fish. The scrim in the blank will have a naturally softer side. With that toward the fish, the rod has no reason to be under torque.

I'm not against the acid wrap, but we tried it on surf rods and comparing that to using the soft side of the spline to the fish we noticed no difference in torque effect between the acid wrap and giving the fish the soft side....

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Spline/spine is often debated as well. It's an 80's theory that has for the most part been replaced by building on the straightest axis. Reason being, you don't fish on just one plane. Tom Kirkman did a rod breakage test  and found that dead lift capacity was lowest when the axis is oriented as you describe. 

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