The AA and ERN are still applicable and relative to all rods. The problem, as you have pointed out, is in using an ERN (IP measurement) to factor a casting or spinning lure weight rating. Rods with extremely fast actions (more than about 70 degrees) tend to "cast off the tip" and not the entire rod. This is the nature of the beast in some cases.

The new equations I presented above should work rather well in most cases with regards to spinning and casting rods. I see nothing wrong with the lure weight ratings given by most of the manufacturers, other than them being consistently a bit on the low end, and recommend using those when possible. Lure weight ratings are the not the problem area when selecting a rod blank - low resolution action ratings and non-relative power ratings are where the problem lies. The Common Cents System has addressed, if not completely solved, both those problems very well.

I think if the builders wish to have a Rosetta Stone chart for casting and spinning lure weights, similar to what you've done for fly lines, it would be a fairly simple matter to come up with one. As I get past the deadline for the next issue and get everything in order for the Charlotte Rod Builders' Show, I'll see what I can put together.

What I don't want to happen, is for us to change the amount of deflection so that you use one constant for one type rod and another for a different type rod. Obviously, this would completely ruin the relative nature of the system, effectively rendering the AA and ERN useless. Or at least no better than the individual systems the manufacturers already use. The deflection must remain constant for all rods, in order to ensure relativity across the board. Beyond that we just need to work up a different translation for lure weight ratings than what we have for the fly line determination. I'll work on it some more after the holidays.
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Just tried one of my favorite blanks with the new equations Tom has given. The St. Croix 3S60MLF.The factory rates it for 1/8 to 3/8 oz. lure weight.This is a super fast blank as evidenced by the AA of 78. It also is very powerful in the butt section.1/8 oz. is not something you would enjoy throwing on it. The ERN comes out to about 13.8 which pretty much is what I would expect on something with the powerful middle and butt section this blank has. Very stiff in those areas for what St. Croix calls an MLF [medium light fast?].

With the new equations the 148 pennies it took to deflect it came out to a lure weight rating of from 3/16 to 7/16 oz. That is more like it! This is an even better lure weight rating than the factory and much more in line with what I know the blank to be capable and best at throwing.1/4 to 5/16 oz. is the best casting weight and that would fall right in the middle of the range given by the new equation.

I still have little need to rely on the common cents method for lure weight ranges but it does seem like the new equations are more realistic if you want to use it for this.Thanks Tom.

I think that there are several very good reasons why blank manufacturers rate their blanks conservatively in terms of lure weight.
1. The tensile strength of the material, graphite or fiber glass, drops as the applied force is applied more rapidly. In other words if you try to cast a long ways and apply a lot of force in doing so, and are asking the rod to deflect very rapidly, the tensile strength of the material will be lower and the rod more likely to break than if you were trying to cast a shorter distance and not asking the rod to deflect quite as rapidly.
2. The toughness or strain energy is lower for higher modulus of elasticity blanks. Or in other words the amount of energy that the rod can absorb during casting is lower.
3. The amount of inertia that the lure has, or how much the lure resists being accelerated during casting, or you could consider it the affective weight during casting, increases very rapidly as you try to cast farther and farther or as you ask the lure to accelerate more and more.
Because rods are sold to big people, strong people, smaller people and people that are not so strong I don't see how the blank/rod manufacturers can do anything other than spec. their blanks/rod very conservatively.
Because the first and third variable above can change dramatically based upon how the rod is used I do not see how any static measurement can give us anything but a very, very coarse indication of what the lure weight should be.

Few rods break during casting unless they have a fracture in them somewhere, and then if they do they are going to break anyway. I have talked to two blank manufacturers during tours and asked about how they design or come up with lure weight ratings and they both said their designers just had a feel for it and knew about how stiff they had to be to cast a certain amount of weight. In other words, they build a blank and shook it and flexed it and said 'this seems about right.' It is not not rocket science. These are just fishing rods. I don't these rod designers really put as much worry into their blanks as we rod builders do!

Static measurements are fine and all you need. If you have a baseline of known weights that are perfect for a number of rods and you know about the average amount of casting effort that gets used then it is a simple matter to come up with a simple static deflection and a reading that can be used to give you a proper lure weight range.

All the fancy rigamoro about dynamic testing and readings is foolhardy at best and unncessary in the least. These are fishing rods. The new equations listed by Tom above seem to be on the money at least for the light to medium freshwater stuff. I suppose anything can be tweaked and will evolve over time but what we have now is only a few months old and yet is already moving more and more towards eventual perfection.

Richard,
You and I have a difference of opinion as well as different experiences. I have seen a number of rods broken by being over stressed by casting too much weight.

I have seen rods broken by casting too much weight, but it was in cases where WAY too much weight was being cast. A rod the factory rates for a range of 1/4 to 1/2 ounce is not going to shatter or bust from casting 5/8 ounce.

The factories are not backing down on casting weight range to prevent breakage. They back down the line weight range to prevent that. They want the line to be the weak point in the chain.

By and large, most fishermen never bother to look at the casting weight range or line weight recommendation. They line the rods with what they think they'll need to keep from losing fish and cast what they feel the rod is capable of. Not the best way to do things but that's how it happens my friends.

In my experience most factory lure weight ratings are too low on the lighter rods and way too high on the heavier rods. Most light power bass rods rated for 1/4 to 1/2 won't hardly load unless you put a full 1/2 on them. Most factory surf rods rated to throw 5 to 8 ounces will barely carry the 5. I have to agree with Richard that the designers don't seem to be using any real science when coming up with the lure weight ratings. It's more of a guesstimate.

Fellows, I think everyone needs to remember that the ERN is a rod power rating, not a lure weight or fly line weight rating. To determine those takes some clever study of the ERN for sure, but heed Dr. Bill's advice on doing THE BIG PICTURE if you want to accurately determine lure weight range. On casting and spinning rods it is the upper 1/2 to 1/3rd of the rod that does the casting, so The Big Picture is the way to go about this correctly.

I do think Tom is on the right track with the new equations and I'll look forward to a fully compiled chart. But for perfect weight ratings I think you'll have to do a Big Picture reading.