For a given spine, the lightest carbon shaft is neither the thinnest nor the thickest
1 study
The summary today
A model says so, with a by-eye comparison against catalogues. The calculation takes a carbon shaft with longitudinal fibres and a spine of about 400 and varies its outside diameter while holding the spine fixed: the thicker the shaft, the thinner the wall, and beyond about six millimetres it becomes too thin to resist crushing. If a minimum wall of 0.45 millimetres is imposed, by adding fibres running around the circumference, the mass first falls and then, past a shallow minimum, rises again: the lightest shaft lies in the middle. Set against five Easton shafts of similar stiffness from the 2011 catalogue, ProTour, X10, ACE, LightSpeed and FatBoy, the curve holds, with the ProTour and X10 slightly below it because they are tapered and a little less stiff; near the minimum sit the ACE and the LightSpeed. The masses, though, are those declared by the manufacturer, the agreement is judged by eye and there is only one make.
Also phrased as: "shaft diameter and weight"; "thick or thin shafts"; "carbon shaft mass"; "grains per inch and diameter"; "indoor and outdoor shafts"
In practice
When choosing shafts, archers hear that for a given spine the thinner the shaft the heavier it is, and that going up in diameter is enough to lighten the arrow.
Evidence
-
2013
For Model Published later
Model of a carbon shaft with longitudinal fibres, spine about 400, length 711 mm, point, nock and vanes 9.27 g: widening the diameter at constant spine thins the wall, and beyond about 6 mm outside diameter it is no longer enough to prevent crushing without circumferential fibres. With an assumed minimum wall of 0.45 mm the arrow's mass first falls to a shallow minimum and then rises as the diameter grows.
The impact of material selection on arrow design and optimal selection for competition · James L Park
-
2013
For Model Published later
The model's mass-diameter relation is compared with five Easton shafts of similar stiffness from the 2011 catalogue (ProTour, X10, ACE, LightSpeed, FatBoy): the author judges the agreement satisfactory, with no error index; the ProTour and X10 sit slightly below the curve because they are tapered and a little less stiff, and the ACE and LightSpeed fall near the minimum. Masses as declared by the manufacturer, not weighed.
The impact of material selection on arrow design and optimal selection for competition · James L Park
Status history
- 2013 Transferred A model of a carbon shaft shows that widening the diameter at constant spine thins the wall until it can no longer resist crushing, beyond about six millimetres without fibres running around the circumference. Imposing a minimum wall of 0.45 millimetres, the mass falls to a shallow minimum and then rises again. The curve agrees by eye with Easton shafts of similar stiffness from the 2011 catalogue, ProTour, X10, ACE, LightSpeed and FatBoy, with the ACE and LightSpeed near the minimum. A model with a by-eye comparison against catalogue masses, not weighed: transferred.
Related
Related articles
Research lines
Cite
Campagna, M. (2026). For a given spine, the lightest carbon shaft is neither the thinnest nor the thickest (Version 1). In Evidence Registry. Retrieved 16 October 2026, from https://matteocampagna.com/en/registry/equipment/lightest-shaft-intermediate-diameter
@misc{campagna2026_astaleggeradiametrointermedio,
author = {Campagna, Matteo},
title = {For a given spine, the lightest carbon shaft is neither the thinnest nor the thickest},
year = {2026},
howpublished = {Evidence Registry, matteocampagna.com},
url = {https://matteocampagna.com/en/registry/equipment/lightest-shaft-intermediate-diameter},
note = {Version 1; accessed 2026-10-16}
}
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