Sometimes the extra mass is beneficial. I like eglass in shorter rods to help the load. I have an 8'1 5wt McFarland rolls for me from eglass. They are not as heavy as in the past.

It could also be said, why use sglass when graphite is lighter and has a better recovery.

I am also a bamboo guy so that could sway my opinion but I like a heavier rod for trout wt rods.
Bob

I think it has to do with the design of the rod that makes it great but the rods I like the most and fish are S glass.The S glass I fish are Steffens and a Scott F2 had a older Lammy S glass but liked their E better........Aurelio
Had the new E glass 5’8” Scott butt my Steffen 6’ loads better in close both are 3wts.

S-glass is probably more attractive to contemporary makers whose market is anglers transitioning from graphite. It has a high-tech ring to it and sounds "new." It isnt; it has been around since the fiberglass era and was used by a few makers when "modulus" became the catch phrase for fly rods (as higher and higher modulus--stiffness--versions of graphite fiber were developed and each was touted in the "IMx" (improved modulus) phase of graphite rod development. And so presenting a fly became "throwing." "Casting," which is where fiberglass excels, letting the rod do the work, was forgotten.

Eglass and S glass have slightly different stiffness. Both excellent materials, the latter slightly more fragile, which is the price paid for increased stiffness. S-glass, being slightly stiffer, may also be attractive to makers and anglers who want 'glass rods in lengths more typical of graphite models.

Both make excellent rods. Corlay nailed it above, and could have added Fisher, Winston, Scott and many others. Smooth, progressive casting comfort--the edge probably goes to Eglass.

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I agree with Corlay, Kenney's e glass rods have a bit of extra heft that brings more "touch" to the rod. Better for casting, better for fishing. I'm not saying his rods are heavy at all, just not overlight. I'd like to try one of Kenneys s glass rods to see if there's any difference.

As I recall, S glass and E glass, in cloth form, are essentially equal weight. Due to its slightly greater “stiffness,” it takes less S glass than E glass for a given taper/length/line weight, making the finished blank lighter (and also more fragile). As others have noted, this isn’t necessarily a plus, depending on what the rod is supposed to accomplish. I’ve had rods of both S and E glass that were superb, and rods of S and E glass that were mediocre to terrible. Since S glass material tends to cost a bit more, there are probably more bad (factory) rods made of E glass, but some of the finest rods I’ve ever cast or owned have in fact been E glass. I currently have three glass fly rods, two of which are E glass, and both rank among the best fly rods I’ve ever owned.

A good rod designer can make any rod out of any material and make it work. But when making the best, material selection can make the designer’s rod easier which can result in an even better fishing rod possible, and in the case of fiberglass, a more durable rod possible. Just as S-Glass has an advantage for its superior low modulus characteristics and durability over graphite for 8ft rods and under, E-Glass has an advantage over S-Glass for shorter and lower weight rods. They have more material to work with where infinitesimal tolerances aren’t quite as necessary to get the desired outcome. It’s all about balance of materials and design. S-Glass is no more the best material for every rod than graphite is. Don’t fool yourself otherwise.

E-Glass all the way for 7ft rods and under and/or 3wt rods!

I have a 5'-5" T&T Graphite that fishes as nice as the short (under 6') E glass and S Glass I have. Yes, the graphite is stiffer in living room wiggling but put a 3wt on it and look out! I believe the differences have more to do with marketing than anything else.

The material properties are measurable. They can be marketed as more or less significant in a given rod type. Glass continues to accept a load when it reaches its limit of elasticity, and gives gradual advance warning by its resilience and flex. Graphite breaks at about its elastic limit. In overtasked light-lineweight rods, that's one reason Crusty's prediction may come true. I hope it doesn't, but there are other characteristics of graphite that make it more vulnerable as well--they may be more or less important to any one user and any one rod design.

Other than that, let's keep it to S and E 'glass--also with slightly different measurable properties--and how these to can be/are used to make good fly rods.

Wow, What a wealth of information. It does make sense to me now. The gradual flexing of the lever to propel the line. Very cool thanks!!