Tom,

I agree from a practical standpoint it's not going to matter in a significant way, as it is tough to beat a sleeved grip in weight and/or rigidity.

That said, why not have the best of all worlds? Carbon skinned foam core, direct blank contact, low mass, low moment of inertia, and even braided line. The blank is a Liberty MB692XF.

[www.rodbuilding.org] (The upload rotated the pic 90 degrees and compressed it a bit making things look wider than they are.)

I use just enough skinned carbon fiber grip to fill my palm and wrap the reel on with thread and finish with the reel placed far enough forward that I can wrap my thumb and finger around the blank. I get to have the benefits of a sleeved foam core grip, a soft edge for my thumb and finger with the EVA trim rings, as well as braided line. If I could figure out how to create an ergonomically correct seatless casting rod, I would be on board.

The last time I measured the before and after masses on one of these builds (excluding the reel was), the added mass of the entire build, both grip sections, guides, thread, and epoxy was comparable to the weight of a reel seat alone, and I know there are some lighter foam cores out there than what I used.

Rather than rely upon hearsay and argument there are instruments which measure exquisitely small movements, movements so small as to be beyond the human sense of touch. These instruments are not rare. A scientific experiment could definitively resolve this question, except for those claiming extra-sensory powers. Apparently no such experiment has been conducted.

Michael,

I agree, if we are only discussing one material vs another, the moment of inertia does not matter, it is the modulus of elasticity and the density. The ability for a medium to carry a signal can be thought of as being directly related to the wave speed in that medium. The higher the wave speed, the better the medium is at transmitting signals in that mode. You'll find that transverse (up/down) waves always have significantly lower wave speeds for a medium than longitudinal (push pull) waves.The speed of a wave through any medium is determined two properties, one elastic, and one tied to mass. For example transverse waves on a string the equation is v = square root(Tension/Linear density) for a solid it is v = square root(modulus of elasticity/density). In that case you are moving the medium just like you do when you grab a rope and shake it up and down.

Now, as I mentioned before, the type of signal that we are feeling is going to come in the form of a torsional wave where the rod is rotating around a pivot point. In this case the speed of the wave is going to be tied to properties that aren't quite as easy to measure or look up in a table. They will be unique to each individual rod. v = square root(torsional stiffness/moment of inertia). In rotational motion, the moment of inertia determines the amount of resistance to change. The higher the moment of inertia, the more difficult it is to start moving and in turn the more difficult it is to stop.

The point is that when considering "feel the bite" sensitivity, the entire rod is the medium through which the signal travels. You can't separate a single element from the whole when considering it. You can think about how swapping one material for another will affect things, but you have to consider all else equal at that point. That may have been the initial intent of the discussion, but wave mechanics are complex in nature. We can make some simplifications to discuss certain concepts, but once we enter real life, things become considerably more complex.


John,

The range of frequencies that contribute to a signal is infinite. The noise that you will feel in the blank is going to be a combination of the blanks fundamental frequency (Common Cents Frequency, CCF) and its harmonics with each harmonic contributing a different amount. As far as the amplitude, the physical rotation of the blank and/or the amplitude of any transverse waves that you feel at the reel seat will be small, at this point the signal will transition to something you experience as a pull on the rod as opposed to a signal you feel in the rod. During that transition you may still feel some noise in the rod (that dull scratchy feeling that doesn't have ticks or thunks embedded in it), just as you hear noise when an object rattles, but is no longer being driven at a frequency you can hear with your ear. The duration of the signal can be estimated based on personal experience and our knowledge of time, maybe something on the order of 0.1s for a tick in the rod, give or take a few hundredths.

double post



Edited 1 time(s). Last edit at 08/10/2020 09:40AM by joseph arvay.

Joe Vanfossen Wrote:
-------------------------------------------------------
> I use just enough skinned carbon fiber grip to
> fill my palm and wrap the reel on with thread and
> finish with the reel placed far enough forward
> that I can wrap my thumb and finger around the
> blank. I get to have the benefits of a sleeved
> foam core grip, a soft edge for my thumb and
> finger with the EVA trim rings, as well as braided
> line.

Good rodbuilding theory and practice there. Fit the tool to the hand well, it works better for the purpose intended. No cramping, hotspots or edges to interfere with hand position with more surface area to the sensor (hand) and multiple points of contact. I have a strong bias to this approach and do the similar, rods are extended use tools and executing the build to be feasible after 4,6, or 8 hours of use (or play) seems to demand certain criteria.

Admittedly, I'm just not that fickle anymore about overall weight comparisons on materials unless the fit-to-user is achieved and the functionality is there. Most weight differences are in an area which seems inconsequential when speaking of reel seating and hand position. A tiny bit more in material weight behind the foremost finger just doesn't move the needle much, it's worth far more than it's weight in fit.