I like some Sage rods, so I'll come to their defense. A Sage ZXL and TCX in a 5wt configuration are certainly not going to feel the same. They are designed to be completely different rods, with completely different purposes. Sage describes the TCX series as one that "redefines the extreme distance
category in rods". A quick look at the ERN chart over at Sexy Loops shows the 590 TCX has an ERN of 7.40, and the 490 ZXL has an ERN of 4.7. My ZXL rods work fine at all distances with a GPX line, so that sounds right.
If Sage made a rod for casting distances, and it had an ERN of 5, it would probably be a dog when trying to cast 100 feet of line. I don't think anyone makes these purchases blindly, and if you buy a TCX, you probably know what it's for. I have a 590 Z-Axis, and it will cast a 4, 5, and 6wt line easily. The soft tip allows it to load in close with the 4wt line, and the stiffer mid and butt allow a 6wt GPX to be cast a fairly good distance without the rod behaving poorly. I use a 5wt GPX most of the time, but have used a 6wt GPX line in strong winds. It allows the rod to flex more deeply, and hurl heavy flies into the wind. The ZXL is never over-lined, and is my all-purpose stream rod.
I would agree that rod manufacturers are deceptive if
they don't describe the particular model's intended purpose. If a Sage rep told me that the 5wt Circa will cast 100 feet of line just as easily as a 5wt TCX, he'd be nuts, but they don't make such claims. When the TXL was being marketed, Sage was very careful to say that while it could cast past 40 feet, that wasn't its intended purpose. I'll never own a TCX type rod, but only because I like 4 and 5 weight rods that cast well in close, and out to 50 feet.
ERN numbers and testing are interesting enough to me, but not evidence of any deception by rod manufacturers. In fact, I suppose many distance casters would get very excited to see that a 590 TCX is rated at 7.40.
"How can you say there is a standard at all when nobody adheres to it? It's kind of the definition of standard isn't it?"
That's actually pretty funny, but raises a good question. How should a standard be arrived at? Do we say that 35 feet is the most line anyone needs to cast, and therefore a measurement of rod deflection with the equivalent of 35 feet of line is the standard? We could say that with distance casting rods such as the TCX, 90 feet is a standard cast, and the amount of force/weight needed to deflect a rod increases. While the 590 TCX might have an ERN of 7.40, I doubt most casters are going to be happy casting a 7wt line at extreme distances with that rod. It's sort of like talking about torque and two different cars. One can generate tons of torque at lower rpm's, while the other needs to get into its mid-range before the torque gets turned on. Which car you buy depends on the type of driving you intend to do.
P.S. Caberguy: What rod did you buy, and have you tried it yet? I wouldn't run out and get a heavier line right away. If you're the type that tears phone books in half, or bends quarters with two fingers, you might do well with the rod's stated weight.