Quote: stiffer? a quick google search shows fiberglass' elastic modulus is 17.2 GPA, steel is 200GPA, so steel is 11.6x stiffer. to get the same effective stiffness, for a same length & width beam segment, the fiberglass spring will need to be approx 2.25x thicker (taller) to have the same spring rate as a comparable steel spring the way the equations work out.
I can't dispute your numbers, they sound correct, but two points, he might have meant comparable weights regrading stiffness, and a "leaf" is not a solid member, but sliding members, where a composite spring is obviously solid.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
