What is the spine?

[dragonheart]

What is the spine of a 2020 aluminum on a spine tester?  The chart at foxfire says 77#, is that correct, I do not have acess to a tester.

[Cupcake]

The 2020 Legacy aluminums are 74 pounds spine.  I have calculated this and verified it on the Spine-O-Meter.  It is simple to calculate an aluminum or carbon:  divide 31.5" by the deflection.

The 2020 is listed by Easton as .426".

31.5/.426 = 73.9

I have verified this calculation with measurements.

[indianalongbowshooter]

I believe thats correct...

[dragonheart]

thanks for the formula and the info.

[sendero25]

I apologize for "hijacking" this thread but this will make it easier to ask a complicated question.
I recently bought some 500 Easton XX75 Gamegetters, which I understand are close to or are 2016s. On the back of the box is an Easton arrow selection chart. The chart shows point weights from 75 to 150 grains. My question is this: Is there a formula to use to determine what spine arrow you should choose if you want to go up in point weight above Easton's recommendations? For example a 190 Grizzly with 100gr steel inserts giving almost 300gr up front. I know bareshafting a several different arrows is the best way, but just wondering if there is a formula to "narrow down" my selections.
Thanks in advance.
John