With today's new methods of fabricating hi-grade steel alloys, parts can be produced stronger and lighter than the aluminum competitor.  Most rocker arms are currently made of aluminum, because aluminum is a lightweight material and is easy to machine.  However, compared to steel, aluminum is much lower in strength (ability to carry the loads) and has a much lower fatigue life, which is the ability to resist breaking under sustained use.  This is why parts made of aluminum need to be three times thicker to make up the difference.   

Steel's advantage where space restraints are important is especially noticable where clearance is critical between the rocker and the valve spring retainer.  Where bulkier aluminum rockers always need last minute grinding for more clearances, Schubeck rockers aford more clearance in this area because high strength steel can be made with thinner wall sections. 

Comparing weight, model for model, Schubeck Rocker Arms are not only 25 grams lighter overall, but are 19 grams lighter at the tip of thre rocker, over the valve.   This is because our light weight roller wheel (only 2grams) saves 19 grams over the heavier (21 gram) steel wheel and axle.  Imagine the potential RPM increase from this weight reduction directly over the valve where it really counts.  It's like throwing away the weight of your spring retainer.