MAT. yes heavy bows do need higher TS.
Not because of what you might think.
People know how to pull a bow back, but on letdown people are not so confident, that are overbowed, tend to grip the bow tight and when they let it down they tend to grip the bow more and let down across their backs and shoulders putting in a lot of torque into the grip of the bow. and this causes Cam derailments as per compound technology.
torsionally stiffer limbs help as the misalignment is pushed more through the grip opposed to the limbs giving way.
more thought:
Lets say the bow has 10lbs (random number) of side load resistance.
A 10lbs bow will be able to take its weight sideways and be ok.
a 20lbs bow if torqued might generate 3lbs of side load. again your ok.
a 80lbs bow might create 10lbs of sideload if mildly torqued, so 10lbs is not enough to stop the limb rotating round.
this second point is different to the first.
the first point is an issue for the 60lbs+ bow weights
as for your question about how much speed would be gained without the TS enhancement.
Well, if you took say anything between 100 GSM and 400gsm of Carbon out a limb, you would pick up about 2-3fps.
not a whole lot in reality.
Your better off using the 100-400gsm to generate more energy. and this is where the bow really takes off.
but its also more stable. since your supporting more string in the string groove.
yes the lever is longer. I fully agree with that. but I think your underestimating what 45deg Carbon can do.
if glass and a wood core as per your broken limb can generate say 5 units of side load resistance. for the same geometry you can generate 70 units with some simple addition of 45 deg carbon. that's not just doubling it. its taking it to the moon and back.
the samick extreme BF limb has mild enhancement., simply because it doesn't need that much more. its taken a stable design, and beefed it up a bit.
how about quadrupling the BF's TS... your question is why? and what would you gain if you did... id agree. We were at that concept in 2001 when we started the Hex2 and hex3 limb design.
We were at that design concept with the ML2 limb.
2007 HEX5 - WCXC (Wood core, CXC laminate, extra high energy recurve ratio)
2007 HEX5 - HCXC ( Hyperflex synthetic core, CXC laminate, extra high energy recurve ratio)
2007 HEX4-WCXC Plus (Wood core, CXC laminate, high energy recurve ratio)
2007 HEX4 - HCXC (Hyperflex synthetic core, CXC laminate, high energy recurve ratio)
2007 CXG (Hyperflex synthetic core, CXC laminate)
2007 CXB (Wood core, CXC laminate)
2004 TXG (Hyperflex synthetic core, TX40 laminate)
2004 TXS (Superflex core, TX40 laminate)
2004 TXB (Wood core, TX40 laminate)
2001 Talisman TX40 Gold (MK2 Hyperflex synthetic core, TX38 laminate)
2001 Talisman TX40 Silver (Superflex synthetic core, TX38 laminate)
2001 Talisman TX40 Bronze (Wood core, TX38 laminate)
1999 ML2 (MK1 Hyperflex synthetic core, glass power structure)
1999 SM Carbon (Wood core, glass power structure)
( ) Carbon (Similar to SM Carbon)
( ) Carbon Premier (Carbons made for Wales Archery)
( ) Merlin Elites (ML2 made for Merlin Archery)
( ) Merlin Classics (Border Carbon)
( ) Carbofast (Similar to SM Carbon)
1998 XP10 Evolution (Synthetic core, glass power structure, stabilization)
1998 XP10 (Wood core, glass power structure, stabilization)
1992 Vision Carbon (Wood core, glass power structure, carbon support)
XP10 stood for CrossX Ply 10. that's 0.010" thick. XP10.