# efficiency

[maxfit]

Read somewhere that a bows efficiency stops at a certain poundage? Any bow over 65lbs or so? A lighter bow is more efficient ? Not sure how to ask, but i am sure someone here will know how to answer. Thanks.

[Featherbuster]

i would like to know that also....................

[zwickeyman]

What I rememder, it's called diminishing returns. After 63# the amount of energy does not increase the same amout with the pound of draw. Energy still increases but not at the same rate. I'm sure someone else can explain it clearer.

[Tree man]

As draw weights increase limb mass must also. There does seem to be a point in the mid sixties where the gains from extra draw weight get smaller. Part of that is due  to the design needs of such stiff limbs but the biggest thing is the difficulty in obtaining proportionately heavy arrows.If you are shooting 500 grain arrows from a 50lb bow energy transfer to the arrow is usually very good. A 650 grain arrow from a 65 pound bow will probably fly at about the same speed but being heavier will possess more energy OR you could shoot a 500 grain from the 65 and its efficiency numbers would be lower than the 650 but it would still be flying faster than the 500 from the 50 and possess more energy. Shoot 1000 grains out of a 100lb bow and it will have more power than the 650/60 but probably not match it for speed. Shoot a 500 grain from the 100lber and it literally mnay fly no faster than a 500/65. There is a limit to how fast heavy limbs can recover.

The limb recovery rate thing is one of the reasons that a deep cored longbow may show quite well in comparison to a same weight recurve or hybrid when shooting 12 grain per pound arrows but gets left in the dust when shooting 8 grains per pound-The bow with lighter limbs can do more with light arrows while a heavy massweight limbed bow reaches the "no speed gain" point quicker as arrow weight is decreased.

The other reason that little is gained beyond 65-70 lb drawweights  is that once you reach the point that it will shoot through any "normal" game animal from almost any angle there isn't anything else to add more for.

[Bonebuster]

There is certainly some gain in performance with higher draw weights, but I agree that the increased performance does not stay in line with the added weight.

Long story short, I have several sets of limbs for my favorite recurve, including 55lbs, 60lbs,
68lbs, and 82lbs.

There is a noticeable performance gain from 60 to 68lbs, and only a slight gain from 68 to 82.
The gain from 55lbs to 60, is very slight. Changing the limbs from 55 to 60 or vice versa, cannot be determined by watching the arrows fly.

[LazerRay]

The increase in poundage v effeciency, if you look at a graph it runs what you call tangent to a vertical line and never touches it. Bettter limb designs will handle the poundage verses effeciency problem. When I what Denny sturgis jr video shooting an 80# bow he gets less pass throughs than fellas shooting lighter poundage bows. I think it may be a waste of time to draw anything past 65# in N. America