Carbon vs Aluminum Arrows: Weight, Strength and Straightness at the Same Spine

For most archers, carbon is the better arrow. At the same spine, Easton's aluminum is 26 to 94% heavier per inch than its carbon, so carbon flies faster and flatter, and in my beam model a same-spine carbon takes about 75% more bend than an aluminum 2213 before it's damaged. Aluminum still wins in three places: indoor target, where the fat shaft cuts more lines; beginners and club racks, where a bent shaft can be seen and straightened; and archers who want a shaft that shows its damage instead of hiding it.

Two things most comparisons get wrong. Aluminum isn't less straight: Easton's XX75 Platinum Plus is guaranteed to ±.002 in, tighter than its own Avance carbon at ±.0025. And a heavier aluminum arrow doesn't hit harder in energy terms; from the same bow its kinetic energy comes out almost identical.

• +57%
  median extra grains per inch for an XX75 size over Avance carbon at the same spine
• 3.5 vs 6.2 in
  center bend on a 28 in span before a 2213 takes a set and before same-spine carbon fails (beam model)
• ±.002 in
  Easton's straightness guarantee on XX75 Platinum Plus aluminum, tighter than its Avance carbon

ArcheryTalk has been arguing this since at least 2012. In a 2022 thread titled "Why so much hate for aluminum arrows", one longtime member put the aluminum side plainly: "Never Worried about a Crack or Splintered Aluminum and Never needed to "FLEX" One Either." I wanted numbers instead of loyalties, so I matched every current XX75 size to a carbon shaft of the same spine and ran both through the same models.

Carbon vs Aluminum Arrows: How Do They Compare?

Here's the whole comparison at a glance, with each row backed by a section below.

Swipe the table sideways to see every column.

Spine pairs: Easton XX75 sizes from my XX75 spine chart against Easton's Avance spine table. Tolerances from Easton's Platinum Plus, Jazz and Avance pages. All numbers in the carbon vs aluminum data (CSV).

How Much Heavier Is Aluminum at the Same Spine?

A lot, and more as the shaft gets weaker. Spine is a stiffness test: the shaft's deflection under a 1.94 lb weight hung at the middle of a 28 in span. Aluminum reaches a given stiffness with a fatter, heavier tube; carbon gets there with stiff fibers in a thin wall. I paired each XX75 size with Easton's Avance carbon at the same spine number.

That penalty is the root of almost every other difference: speed, trajectory, FOC and momentum all follow from the extra grains. It also explains why aluminum hunting arrows run so heavy without trying.

Are Carbon Arrows More Durable Than Aluminum?

Carbon takes more bending before it's damaged; aluminum is easier to live with after it is. That's the honest answer, and it comes out of the same beam math as the spine test.

In the spine test, the strain at the surface of the shaft depends only on the deflection, the diameter and the span: strain = 12 × deflection × radius ÷ span². Easton rates XX75 Platinum Plus at 96,000 psi in 7075-T9 alloy; divided by aluminum's 10.4 million psi modulus, that's about 0.92% strain before the tube takes a set. For carbon I used a common arrow-grade fiber: Toray's T700 composite data gives 1,450 MPa compressive strength on a 134 GPa modulus, about 1.1% before the compression side fails.

For a 2213 and a same-spine carbon, that works out to about 3.5 in of center bend before the aluminum is permanently bent and about 6.2 in before the carbon cracks: roughly 7.6 and 13.3 times the bend of the spine test itself. Carbon gets the extra room from two places, a slightly higher strain limit and a thinner shaft, which strains less for the same curvature.

What happens past the limit is the real difference. Bent aluminum is visible and often straightenable; forum archers describe straightening their own with a tool. A cracked carbon shaft may look fine, which is why carbon shooters flex-test and listen for cracking before they shoot one again. A carbon arrow that fails can also splinter, which aluminum can't.

Are Carbon Arrows Straighter Than Aluminum?

Not by Easton's own numbers. Straightness is a manufacturing grade, and both materials come in tight and loose grades:

From each Easton product page, and the 18 hunting shafts in the Arrow Shaft Finder.

Carbon's real edge is weight consistency: ±1 grain per Avance shaft against ±1% for aluminum, which is close to ±3 gr on a 29 in 2213. Where aluminum loses straightness is in use: a shaft that's been bent and straightened is only as straight as the person who did it.

Carbon or Aluminum for Hunting?

From the same bow, aluminum trades speed for momentum and lands at nearly the same kinetic energy. I built each pair with a 125 gr broadhead on the same insert and vanes, spine-matched with the model the Arrow Shaft Finder uses:

Swipe the table sideways to see every column.

340 fps IBO, hybrid cam. At 70 lb no current XX75 hunting size is stiff enough; the 2317 is the closest and would need tuning. Gr per sq in is finished weight divided by the shaft's cross-section.

The surprise is the last-but-one column. Aluminum's extra weight goes into a fatter tube, so per square inch of frontal area it carries no more than a standard 6 mm carbon, and less than the thin carbons in my best arrows comparison. If you want a heavy hunting arrow, a heavy carbon with weight up front gets you there on a thinner shaft and with more FOC. The KE and momentum calculator shows where your build lands.

Carbon or Aluminum for Recurve and Beginners?

For target recurve, the weight gap takes speed off every shot. I matched each draw weight to Easton's target-chart spine and built 28 in arrows with 100 gr points:

Swipe the table sideways to see every column.

28 in draw, 28 in arrow, 72% limb efficiency, so kinetic energy stays the same for both shafts. Aluminum is the nearest XX75 Platinum Plus or Jazz size to the chart spine; carbon is Avance interpolated at the chart spine.

Beginners still do well with aluminum. It's consistent, it tells you when it's bent, and a club can straighten it. A 10 to 15% speed loss matters little at 18 m. As the distances grow, carbon's flatter flight starts to show on your sight marks. For the spine itself, use the recurve spine calculator.

Are Aluminum Arrows Better Indoors?

Yes, and here the fat shaft is the point. An arrow that touches a scoring line scores the higher ring, so diameter buys points. In my line-cutter model, a 9.1 mm aluminum 2315 adds about 3 points per 60 arrows over a 6.7 mm carbon on a 40 cm face, with the same group. World Archery caps shafts at 9.3 mm.

What About Carbon-Aluminum Hybrids?

There are two kinds, built in opposite ways. Easton's Full Metal Jacket wraps an aluminum jacket around a carbon core, a hunting shaft I compared in Easton Axis vs FMJ. Target shafts like the X10 do the reverse: carbon fiber bonded over a 7075 aluminum core, the thin barreled shafts Olympic archers shoot. See alloy-carbon arrows for the target side. The Arrow Comparison Engine puts X10, A/C/E, A/C/C and other target shafts side by side at one spine.

What Do Archers Actually Argue About?

Bending and breaking come up so often because they're the two failure modes, and the numbers above explain both: aluminum yields first and visibly, carbon holds longer and then fails for good.

Shoot aluminum and think I've got the durability model wrong? Tell me through the contact page.

Frequently Asked Questions