From a 2007 Easton Arrow Catalog I believe.
Size Spine Weight/Inch Weight Gr/In

Shaft	Spine Size (inches)	Weight (grains)	Weight (gr/in)
1214	2.501	142 - 24"	5.92
1413	2.036	153 - 26"	5.88
1416	1.684	194 - 27"	7.19
1512	1.554	157 - 27"	5.81
1514	1.370	184 - 27"	6.81
1516	1.403	197 - 27"	7.30
1612	1.298	170 - 27"	6.30
1614	1.153	208 - 27"	7.70
1616	1.079	227 - 27"	8.41
1712	1.099	181 - 27"	6.70
1713	1.044	200 - 27"	7.41
1714	0.963	219 - 27"	8.11
1716	0.880	261 - 29"	9.00
1813	0.874	228	7.86
1814	0.799	249	8.57
1816	0.756	269	9.28
1912	0.776	220	7.59
1913	0.733	242	8.34
1914	0.658	269	9.28
1916	0.623	291	10.03
2012	0.680	232	8.35
2013	0.610	261	9.00
2014	0.579	277	9.55
2016	0.531	306	10.55
2018	0.464	356	12.28
2020	0.426	391	13.48
2112	0.590	244	8.41
2113	0.540	270	9.31
2114	0.510	286	9.86
2115	0.461	312	10.76
2117	0.400	349	12.03
2212	0.505	256	8.83
2213	0.460	285	9.93
2214	0.430	302	10.41
2215	0.420	309	10.66
2216	0.375	349	12.03
2219	0.337	399	13.76
2311	0.450	242	8.36
2312	0.423	275	9.48
2314	0.390	309	10.66
2315	0.340	338	11.66
2317	0.297	385	13.28
2412	0.402	280	9.66
2413	0.365	302	10.41
2419	0.268	422	14.56
2511	0.348	233	8.1
2512	0.321	298	10.28
2514	0.305	329	11.34
2612	0.285	280	9.68
2613	0.265	333	11.48
2712	0.260	275	9.5

 

I've never seen an actual chart from Easton for spine ratings until now, but there's a ton of them that wil give you a range for what you need.

 

Yes Easton use a different sizing system for Aluminum arrows. The 4 numbers represent the outer diameter of the shaft and the wall thickness. So a 2312 is a 23/64 shaft with a 0.012 wall thickness. So a 2315 is stiffer than a 2312 since it has a thicker wall.

Here are the equivalencies that OT2 give me for the X23

2312 = 423
2314 = 391
2315 = 340
2318 = 300

 

Thanks for the replies and the chart!

Depending on the arrow material (aluminum, carbon, mix), wouldn't the stiffness differ? An arrow made out of paper would be (much, much) less stiff than an arrow made out of aluminum.

 

Yes, this chart is only valid for Easton aluminum arrows. For anything else you will need to refer to the spine chart for the specific arrow model you are looking at

 

@ GuiTeK - from Easton's 2023 target catalogue, page 16, lower left corner:
2312 ------.429
2314-------.397
2315-------.348
2318-------.304
They're slightly different than what fgignac's OT2 shows.

 

Would go with the Easton spine chart seeing they started it. Like Carbon Express started a different spine to what is marked on the shaft & screwed it all up. Easton has 100+ years in the arrow shaft business & CE may have 25 years.

 

I've wondered about CX over how they give spine. Thing is, PSE followed CX. I have PSE 200s.

 

For their other arrows (such as the Superdrive 23), the spine is expressed as usual with the deflection in thousands of inch.

Normally spine value is in fraction of an inch.
Thus, the table value times 1000.

...it seems they just give the arrow diameters: 2312, 2314, 2315...

These are the arrow diameter and wall thickness combined into one number.
If I remember correctly, each in 1/64-th of an inch. But you can look it up.
In your example (2312, 2314, 2315), all shafts have the same outer diameter, but increasing wall thickness.

From a customer's point of view, I find the idea of standardized IDs like with carbon shafts more practical (.166", .204", .245").

 

Normally spine value is in fraction of an inch.
Thus, the table value times 1000.


These are the arrow diameter and wall thickness combined into one number.
If I remember correctly, each in 1/64-th of an inch. But you can look it up.
In your example (2312, 2314, 2315), all shafts have the same outer diameter, but increasing wall thickness.

From a customer's point of view, I find the idea of standardized IDs like with carbon shafts more practical (.166", .204", .245").

First number is in /64th of inch but second number is actually in thousandth of inch.

Thanks everyone for the answers, it's much clearer now!

 

A 23XX shaft is commonly referred to as having a 23/64 inch OD diameter but this is only a nominal dimension.
The actual outside diameters in thousandths of an inch are shown in the catalogue -
2312 ------.363
2314-------.357
2315-------.365
2318-------.365
Expressed in millimetres, they're all in the 9.3 mm group.

 

2315 is OK under World Archery rules. 2317 is not.

 

They are both the same OD so don't see why they wouldn't be. There are no advantage of one over the other as far as line cutters.