I got a test pack of  surewood  shafts ranging from 55-60 to 80 -85. I was looking for arrows for my 65 @26 centaur.  I set them  up with 160gr.tips  and cut them to 28 inches from throat of nock to bop.  For fun I started testing the shafts through paper with my 47 @ 26 centaur.  I started with the lightest spine shafts and they were tearing a little high.  As I went up in spine they flew better and better until I was punching perfect holes with the 80-85 spine.  Is it weird to have these results?   I than went through the test pack with my heavier bow and none of them flew good.  All tearing high.
I would have guessed my little centaur would have preferred the 55-60 shafts???

Depending on center cut and string material with the point weight and arrow length compared to draw length that sounds about right to me. If they fly good then there ya go.

Hey TFG - where did you get the Surewood shaft test pack?

Thanks.

Shoot straight, Shinken

 

I know Ron LaClair always told me start +15 when using Super Shrew bow (he was using 6 strand 450+ strings on his bows at the time). So with a similar style of bow, you've got -5 for arrow 1 inch less than 29" and +7 for point weight (I use 1# for every 5 grains over 125 grains). Therefore I come up with 65+15-5+7=82 pound spine. Sounds like you are right there.

That last answer is why my spine search always starts with a call to Ray  

Your specs are stated at 26" vs 28". Just for fun check your draw again-maybe your arms got longer?    
The fact that you are shooting the 80/85 with perfect holes from the lighter bow 47@26 or low 50's@28 is a bit unusual for a 28 BOP shaft-once fletched they might be a tad stiff..............I'd step down one spine group and fletch the slightly weaker shaft.
Clearly you will need a lot more spine for the heavier bow-almost 20# heavier, so you'll need shafting with correspondingly more spine. Don't get hung up on the 'boy these are 40# heavier  than my bow weight' it is only numbers and how they fly is all that counts.  Adding carbon to limb sandwiches increases spine requirements, and skinny strings will add spine needs too.
Let us know how you make out. If nothing else you got a great test pack for the weaker bow!      

Shinken,  I ordered the test pack straight from surewood  off of the website.
  .  I probably do gain an extra inch with that light bow
 I am very pleased with the quality of these shafts so far, very straight and consistent.
  Thanks for the help.

Shinken,  I ordered the test pack straight from surewood  off of the website.
  .  I probably do gain an extra inch with that light bow
 I am very pleased with the quality of these shafts so far, very straight and consistent.
  Thanks for the help.

Yeah, you're right on. My decidedly unscientific method for determining a general spine group is very similar to what Ray said.

Bow poundage: 47
Aggressive r/d: 10
FF string: 10
Arrow length: -5
Point weight: 10
Cut past center: 10
Total: 82