Arrow spine for a 45 lb compound at a 30 inch arrow with a 100 grain point: a 400 spine (band 400-500), plus the 225 grain minimum weight. Sourced.
Updated 05 September 2026.
What arrow spine for 45 lb draw at a 30 inch arrow
The starting spine for a 45 lb draw at a 30 inch arrow with a 100 grain point, and the weight floor.
| Draw weight | 45 lb |
|---|---|
| Arrow length | 30 in (cut, nock groove to shaft end) |
| Point weight | 100 gr |
| Recommended spine | 400 (published band 400-500) |
| Minimum total weight | 225 gr, from the 5-grains-per-pound floor |
Easton 5mm Axis carbon arrow shaft (400 spine)
Shop Easton 5mm Axis carbon arrow shaft (400 spine) on AmazonaffiliateFind Easton 5mm Axis carbon arrow shaft (400 spine) on eBayaffiliateField notes
A 45 lb draw at a long 30 inch arrow flexes enough to move up from the 500 a short cut would take to the stiff end of a 400. Long-draw light bows sit stiffer than their weight alone suggests.
Spine is a starting point, not a guarantee, because a 340 from one brand can differ from another. Confirm on your arrow maker's chart at 30 inches and 45 pounds, or bare-shaft test before cutting a dozen.
Whatever spine you land on, keep the finished arrow at or above 225 grains total, the 5-grains-per-pound floor, so the bow is not shooting dangerously light.
The rules behind this pick
Questions and answers
What arrow spine for 45 lb draw at a 30 inch arrow?
For a 45 lb draw at a 30 inch arrow with a 100 grain point, start with a 400 spine (the 400-500 band), and keep the finished arrow at or above 225 grains total.