spine numbers

[La. bowhunter]

In the arrow charts that list spine deflection numbers are the higher spine deflection numbers stiffer or weaker.

eg..2016  spine 530
    2413  spine 325

which one is stiffer

[La. bowhunter]

Yhe reason I am asking is I bought a bow a couple of days ago and the guy I bought it from gave me a couple of arrows to shoot and they shoot really good but they are really light.

They are 2013's 28 inches long with a 125 tip. I am trying to find an arrow of similar spine that weighs about 100 to 125 grains more.This arrow weighs about 400 grains I would like 500 to 525.

[aromakr]

La.:
Spine is a math formula 26" divided into the deflection = poundage. i.e. 26 divided by .530= 49# & 26 divided by .325= 80#
Bob

[La. bowhunter]

Thanks Bob that gives me an idea of what Im doing ...Maybe

[La. bowhunter]

so what happens to this formula when I change the weight of the point how much spine do I lose when I add say 10 grains to the point. what grain point is used to get the deflection numbers used in the charts.

[TexMex]

La for woods you measure in the middle of the 26"'s with a 2lb weight.
I have heard the for alumium and carbon your distance is 28" with a 1.94lb weight.

[aromakr]

The industry standard is 125 grain point, its difficult to tell you what 10 grains will do as it depends where the arrow you are now shooting falls in your usable spine range. Lets say your usable spine range is 50-60# spine and your arrows spine 50#, 10 additional grains of point you will need to increase to the next spine, but if your arrows spine 60# 10 grains probably will not effect things. Hope this helps.
Bob

[kyhuntertoo]

spine is measure from an arrow cut 29 inches.  two points of contact are made , 28 inches apart.  a weight (I thought it was 1.96 pounds, but whatever)  is hung in the middle.  the number you get .500, .325, whatever, is the distance in inches that the shaft sags from parallel (it's original position).

[kyhuntertoo]

i might add, what I was referring to is static spine.  dynamic spine is how much deflection is created during flight. I do not know if and or how that is measured.

[aromakr]

Kyhuntertoo:
I think you should recheck your source. Spine for traditional arrows is measured between 26" centers with a 2# weight, that gives you the spine for a 28" arrow. Its been that way for many years.
Bob

[kyhuntertoo]

La.  This maybe a good read for you  http://www.huntersfriend.com/2007-Carbon-Arrows/arrow-selection-guide3.htm.   To answer your original question, the 2413 is stiffer (assuming the spine numbers you mentioned are correct)