Gold Tip Arrow Spine Advice Needed

[John Whitaker]

I have been using Stu’s Calc to get an idea of spine for some new arrows and these are the numbers that I came up with. The main question I have is concerning all the post that talk about how “stiff” carbon arrows are and folks seem to be using lighter than listed spines.
I have 2 Mohawks 49#@28 and 53#@28 and I am drawing 30” so I’m looking at 31.25” for a total length (shooting 32’s right now).
What do you think these numbers as a starting point or am I starting off to stiff in spine?

Mohawk 49@28 30” draw
Stu’s Calc with GT 5575 Traditional
31.25”BOP
150gr point (Woodsman for BH)
50 gr brass insert
3X5 feathers
= Dynamic Spine of 52.4
TW = 511gr  9.3gpp  17.7% FOC
Using Generic Deflex/Reflex Longbow 49#@28” 30” Draw 3/16 for Center cut # (not past)
and 14 Strand Fast Flight. = 52.5 Arrow Dynamic Spine Required


Mohawk 53@28 30” draw
Stu’s Calc with GT 7595 Traditional
31.25”BOP
175gr point (Woodsman for BH)
100 gr brass insert
3X5 feathers
= Dynamic Spine of 56.9
 TW 639gr 10.8gpp 20% FOC
Using Generic Deflex/Reflex Longbow 53#@28” 30” Draw 3/16 for Center cut #(not past)
and 14 Strand Fast Flight. = 57.2 Arrow Dynamic Spine Required

Thanks
John

[Green]

Looks like you're right on the money with the arrow choices for these bows as long as you're on the money with your center cut figure.  Try 'em and see....you may have to make minor brace height adjustments if they're a little stiff or weak, but that's all it should take.  I've used the calculator to test in 4 different spine weights of Douglas Fir shafts for two bows of 57/60#, plus a set of Beman MFX carbons in the past 10 days....the calculator really saved me time & money in the tuning department.

[KHALVERSON]

sounds right to me
i shoot bows with the same specs alltho they are recurves center shot with a 30 in draw thats what i shoot and they  bareshaft a touch weak but fly great fletched

[onewhohasfun]

56 @ 30" here. 55/75 with 300 grn up front for me. Plus a 100 grn insert. Mine are full length. I think 35/55 for the lighter one and 55/75 for the other. You should be able to get by with one shaft for both by playing with your tip weight.

[Eugene Slagle]

Um the only thing I see wrong is the actual shaft lengths.
Gold Tip Trad shafts come in 30" length well 30.5" if you include the nock.

OK I am mistaken & apologise, I just looked on the Gold Tip sight & they show the 55/75 & 75/95 in 32" length.

With that in mind then yes I too see no problems with that set up.

Edited to apologise.

[sffar]

That formula would closely match my 51# Mohawk, though The center cut you're using is probably a little high unless you built it out. Vince at Mohawk told me he goes for between a sixteenth and an eighth. I've been using an eighth in my own calculations.

[Jim Wright]

I have shot similar set-ups and would find myself a bit over-spined with yours but with differences in form and bows it may work for you. If you have problems however, I would suspect spine stiff.

[TD2]

35-55's!  stay away from a 55-75 (spines for a 80 pound bow)

[Eugene Slagle]

Originally posted by TD2:
35-55's!  stay away from a 55-75 (spines for a 80 pound bow)

If you go by the numbers he has there & punch them into Stu's Calculator they are right on the money for the length of arrow he's using.

The 55/75's could be used for both bows just reduce the weight up front fror the heavier bow.

[TD2]

i go by my real world experiances, not a calculator. your mileage may vary, but not by much I bet.

simple enuff, bare shaft them...at 20 and beyond not ten yards

[Ron+dog]

Originally posted by Eugene Slagle:
 

Originally posted by TD2:
35-55's!  stay away from a 55-75 (spines for a 80 pound bow)

If you go by the numbers he has there & punch them into Stu's Calculator they are right on the money for the length of arrow he's using.

The 55/75's could be used for both bows just reduce the weight up front fror the heavier bow. [/b]

3555 dont come as long as he needs them

[John Whitaker]

So I went to the range with my 53# Mohawk and some full length (32")55-75's tipped with 175gr FP's. As per Stu's calc they should be weak by about 8lbs and the bare shafts flew right (4-6") of my group. As soon as I went to a 145gr point I was putting them almost in the same group. So I'm guessing the calc is pretty darn close at least for my arrows. BTW all this was done at 20 yards.
Given this info and the imput from most here, I think that Stu's numbers for both bows are a good starting point for the weights I want to achieve.

Thanks
John