Diameter chart, reel capacity & backing guide
J-Braid X4 is Daiwa's four-strand mainline. This guide uses the US Dark Green SKUs, keeping their 150-, 300-, and 3,000-yard packages distinct from the metric packages and rounded labels sold elsewhere. The X4 chart is not the same as the X8 or Grand X8 chart.
Consider X4 when a four-carrier braid suits your setup and compare the exact diameter before choosing a spool. Carrier count describes construction; it does not certify abrasion performance in your conditions. Select strength around the tackle and cover, then use capacity to plan the amount.
US Dark Green SKUs only. Published inch/mm pairs retained. The conflicting 6lb pair is excluded; 150/300/3000-yard lengths are verified by exact row.
| Strength | Inches | mm | Spools (yd) |
|---|---|---|---|
| 8 lb | 0.005 | 0.130 | 150, 300, 3000 |
| 10 lb | 0.007 | 0.170 | 150, 300, 3000 |
| 15 lb | 0.008 | 0.190 | 150, 300, 3000 |
| 20 lb | 0.008 | 0.210 | 150, 300, 3000 |
| 30 lb | 0.010 | 0.250 | 150, 300, 3000 |
| 40 lb | 0.011 | 0.290 | 150, 300, 3000 |
| 50 lb | 0.013 | 0.330 | 150, 300, 3000 |
| 65 lb | 0.014 | 0.360 | 150, 300, 3000 |
| 80 lb | 0.017 | 0.420 | 150, 300, 3000 |
For a 10 lb X4 fill, use its listed .007 inch / .17 mm diameter when estimating reel capacity. A .006 inch figure from a different J-Braid model is not interchangeable.
The US X4 20 lb and 15 lb rows both round to .008 inch, but their metric labels are .21 and .19 mm. At this display precision, equal inch labels do not mean identical physical diameters.
The 6 lb pair is withheld because .003 inch and .10 mm do not reconcile within ordinary displayed rounding. The page starts at the independently coherent 8 lb row.
Specification-based guidance, not a hands-on J-Braid X4 test. Capacity results are estimates, not measured fills.
The verified Dark Green SKUs list 150, 300, and 3,000 yards. Match the exact model number and unit on the spool you receive; do not turn a 150-meter package into a 150-yard entry.
Follow the reel maker's braid attachment instructions. Where a mono backing layer is used for grip, include it in the fill plan rather than treating the entire reel as empty.
Before casting again after a hard pull, check for buried or loose wraps and damaged working line. A four-strand label does not remove these basic line-management checks.
No. At 10 lb, the verified X4 diameter is .17 mm; another J-Braid model is not interchangeable evidence.
The official page lists it. It is withheld here because its published inch/mm pair conflicts, not because stock availability was established.
No. They use listed diameters and reel capacity references. Winding tension, line shape, and fill level affect the actual result.
Checked 2026-09-13 against Daiwa's product-linked public LINES data. Existing catalog values are not evidence. The 6lb pair needs manufacturer clarification; this page does not silently replace it.
Calculations use the catalog's listed inch diameters. Published inch and millimeter values may differ slightly because of rounding.
Diameter chart, reel capacity & backing guide
J-Braid X4 is Daiwa's four-strand mainline. This guide uses the US Dark Green SKUs, keeping their 150-, 300-, and 3,000-yard packages distinct from the metric packages and rounded labels sold elsewhere. The X4 chart is not the same as the X8 or Grand X8 chart.
Consider X4 when a four-carrier braid suits your setup and compare the exact diameter before choosing a spool. Carrier count describes construction; it does not certify abrasion performance in your conditions. Select strength around the tackle and cover, then use capacity to plan the amount.
US Dark Green SKUs only. Published inch/mm pairs retained. The conflicting 6lb pair is excluded; 150/300/3000-yard lengths are verified by exact row.
| Strength | Inches | mm | Spools (yd) |
|---|---|---|---|
| 8 lb | 0.005 | 0.130 | 150, 300, 3000 |
| 10 lb | 0.007 | 0.170 | 150, 300, 3000 |
| 15 lb | 0.008 | 0.190 | 150, 300, 3000 |
| 20 lb | 0.008 | 0.210 | 150, 300, 3000 |
| 30 lb | 0.010 | 0.250 | 150, 300, 3000 |
| 40 lb | 0.011 | 0.290 | 150, 300, 3000 |
| 50 lb | 0.013 | 0.330 | 150, 300, 3000 |
| 65 lb | 0.014 | 0.360 | 150, 300, 3000 |
| 80 lb | 0.017 | 0.420 | 150, 300, 3000 |
For a 10 lb X4 fill, use its listed .007 inch / .17 mm diameter when estimating reel capacity. A .006 inch figure from a different J-Braid model is not interchangeable.
The US X4 20 lb and 15 lb rows both round to .008 inch, but their metric labels are .21 and .19 mm. At this display precision, equal inch labels do not mean identical physical diameters.
The 6 lb pair is withheld because .003 inch and .10 mm do not reconcile within ordinary displayed rounding. The page starts at the independently coherent 8 lb row.
Specification-based guidance, not a hands-on J-Braid X4 test. Capacity results are estimates, not measured fills.
The verified Dark Green SKUs list 150, 300, and 3,000 yards. Match the exact model number and unit on the spool you receive; do not turn a 150-meter package into a 150-yard entry.
Follow the reel maker's braid attachment instructions. Where a mono backing layer is used for grip, include it in the fill plan rather than treating the entire reel as empty.
Before casting again after a hard pull, check for buried or loose wraps and damaged working line. A four-strand label does not remove these basic line-management checks.
No. At 10 lb, the verified X4 diameter is .17 mm; another J-Braid model is not interchangeable evidence.
The official page lists it. It is withheld here because its published inch/mm pair conflicts, not because stock availability was established.
No. They use listed diameters and reel capacity references. Winding tension, line shape, and fill level affect the actual result.
Checked 2026-09-13 against Daiwa's product-linked public LINES data. Existing catalog values are not evidence. The 6lb pair needs manufacturer clarification; this page does not silently replace it.
Calculations use the catalog's listed inch diameters. Published inch and millimeter values may differ slightly because of rounding.
