The weight of a rotor on a spinning reel and the performance of the same.

[Glos]

Do smaller sizes not need that inertia? Methinks they did it to reduce weight without losing the strength in the gear box.

They do, but we on the other hand, don`t. Results and differences are minuscule.

Gear box will have to work a bit harder, driven by us, when rotor is lighter.

[Glos]

I`ve finally found a proof.

: 
X RIGID ROTOR

SHIMANO's X Rigid Rotor is an extra strong and durable rotor. The shape and thickness of the aluminium rotor creates high rigidity that results in more fish fighting power. Increased mass of the aluminium rotor generates more inertia resulting in easier fishing of heavy jigs and high resistance lures.

[JasonGotaProblem]

I`ve finally found a proof.

: 
X RIGID ROTOR

SHIMANO's X Rigid Rotor is an extra strong and durable rotor. The shape and thickness of the aluminium rotor creates high rigidity that results in more fish fighting power. Increased mass of the aluminium rotor generates more inertia resulting in easier fishing of heavy jigs and high resistance lures.

Leave it to shimano to find a way to spin being heavier into a good thing, AND as usual they gave it a marketing name.

[Glos]

It`s not heavier. It`s easier, due to inertia.
The weight alone is beneficial.

[jurelometer]

I`ve finally found a proof.

: 
X RIGID ROTOR

SHIMANO's X Rigid Rotor is an extra strong and durable rotor. The shape and thickness of the aluminium rotor creates high rigidity that results in more fish fighting power. Increased mass of the aluminium rotor generates more inertia resulting in easier fishing of heavy jigs and high resistance lures.

Very much the flywheel effect.


Daiwa wants to convince us that the low inertia  rotor is better:

AIRDRIVE ROTOR
Low inertia is the key.
The newly developed AIRDRIVE ROTOR is made from ZAION. Maintaining the strength of the rotor from 18 EXIST, DAIWA has been able to reduce the weight significantly. Designed with focus to create a perfectly round structure, trouble free and flawless rotation have been achieved.

Source: https://www.daiwa.com/scandinavia/technology/index.html


I don't think that  anything a fishing reel company puts in marketing text is proof of anything.

The lighter the rotor, the less energy it will take to mostly start, but also keep moving (advantage: Daiwa).  I.e., lower inertia.  This will help for start and stop winding mostly, with some minimal benefit winding under heavy load.

The heavier the rotor, the more energy to start and and keep moving, but the greater tendency to maintain rotational velocity (momentum, NOT inertia).  This could make turning the handle less jerky in a specific range of  velocity and resistance (advantage: Shimano).  This would help  when retrieving lures that change resistance during a speed wind, and is in line with what Shimano is attempting to claim.

Inertia is the resistance to change in speed and is a function of mass.   Momentum is the tendency to maintain speed and is a function of mass and velocity. The momentum benefit of a heavier rotor will vary depending on a combination of resistance and velocity.  Low inertia is  desirable, but so is high momentum. Problem is that it is hard to get high momentum without high inertia. Shimano should be touting the momentum and not the inertia...

The exact ideal rotor mass will be a balancing act, taking in the winding resistance in the reel mechanisms, resistance from pulling payload, winding speed, and how much inertia to start winding from a dead stop is worth putting up with.

Plus the reel designer has to take into account overall weight, rigidity, and other factors.  Each choice is a tradeoff.  But the marketing babblespeak will try to convince us that every tradeoff has no downside and is actually some sort of brilliant technical advantage

-J

[Midway Tommy]

I don't think that  anything a fishing reel company puts in marketing text is proof of anything

I`ve finally found a proof.


Each choice is a tradeoff.  But the marketing babblespeak will try to convince us that every tradeoff has no downside and is actually some sort of brilliant technical advantage

-J

 
In today's environment they call it mis, or dis, information. In yesteryear it was called advertising propaganda. 

What matters most to me is balance. When I'm playing or working a fish none of that other stuff really matters.

[Glos]

Thx Jurelometer. Good one.
Its not my language so I tend to simplify and misunderstand, write.

There is a good example in a new freshwater or inshore Stela, where is that sweet spot.
They make the rotor from magnesium up to size 2500, and above that from ( heavier ) aluminium...
I knew right away why is that so.

[jurelometer]

No worries Glos.  It appears to me that your proficiency in  English is  better than the marketing folk at Shimano

We are all learning here, and this discussion has helped me as well.

-J

[Glos]

They may have missed the proper term in physics, but they sure nailed it by logic.
And physics - laws.
Btw I`ve sent that quote to Alan Hawk also.
He wasn`t convinced in my claims .. also.

[philaroman]

There is a good example in a new freshwater or inshore Stela, where is that sweet spot.
They make the rotor from magnesium up to size 2500, and above that from ( heavier ) aluminium...
I knew right away why is that so.

and you were wrong...  nothing to do with weight/inertia
MG stops at 2500-size because it can't handle S/W...  otherwise, 
as rotor/frame material, it's stronger, lighter, better than AL in every way
no matter how much they try to minimize "fear of salt" w/ alloys & coatings,
MG is still most appropriate for smaller lighter reels, that are mostly F/W

IMHO, if all other factors are same: rigidity/strength/durability,
then comparatively lighter rotor is better regardless of reel-size

[jurelometer]

IMHO, if all other factors are same: rigidity/strength/durability,
then comparatively lighter rotor is better regardless of reel-size

Not a spinner guy- so I am not 100% confident, but I am inclined to mostly agree with you.  The benefit of less inertia going to win out in most use cases. Especially in larger reels. The smaller the reel/rotor, the harder it will probably be to notice as much difference either way. 

This matches Tommy's observation that balance is mostly what matters.  Tommy has played with a lot more models of spinners than I have (probably several hundred more, and more small than large).

I took a quick look at the Shimano site, and it looked to me like the magnesium Exsense spinner has magnesium body and rotor.

Of course Shimano does a complete reversal now and touts the benefit of less inertia with a light rotor:

The magnumlite MGL rotor is 25% lighter, contributes to better balance, and requires less start up inertia allowing anglers to control the start-and-stop retrieval of jigs and lures more efficiently.

Source:https://fish.shimano.com/content/fish/northamerica/us/en/homepage/Shimano_Product_Page.P-EXSENCE.html



And then more grammatically incorrect marketing babblespeak about "Infinity Evolution" which I think means "Good luck getting parts for that $USD 1000 reel five years from now."

-J

[handi2]

There is a good example in a new freshwater or inshore Stela, where is that sweet spot.
They make the rotor from magnesium up to size 2500, and above that from ( heavier ) aluminium...
I knew right away why is that so.

and you were wrong...  nothing to do with weight/inertia
MG stops at 2500-size because it can't handle S/W...  otherwise,
as rotor/frame material, it's stronger, lighter, better than AL in every way
no matter how much they try to minimize "fear of salt" w/ alloys & coatings,
MG is still most appropriate for smaller lighter reels, that are mostly F/W

IMHO, if all other factors are same: rigidity/strength/durability,
then comparatively lighter rotor is better regardless of reel-size

Yes a lighter "carbon infused" Shimano ci4 rotor is what most like better than a heavy rotor making a heavy reel.


Magnesium is a no no

[handi2]

They may have missed the proper term in physics, but they sure nailed it by logic.
And physics - laws.
Btw I`ve sent that quote to Alan Hawk also.
He wasn`t convinced in my claims .. also.

And you still believe yourself?

The mass of the rotor has nothing to do with anything. Tommy nailed it.

[Glos]

Handy Andy it does pretty much as the weight, not casting weight artificially incorporated by making the rod tip stiffer, but physical weight, of the rod tip, makes it better at hooking up and penetrating.
                         Together with some bendability of the same.
Both would be counter intuitive for the novice, but not for the physicist.