Daiwa J-Braid X4 Braid

Diameter chart, reel capacity & backing guide

J-Braid X4 is Daiwa's four-strand braid main line, separate from J-Braid X8 and Grand X8. Compare its strength-specific diameters and available package lengths, then plan a full fill or a working section over backing for your reel.

Construction: Four-strand woven braid
Listed strengths: 8-80 lb
Line type: Braid main line

Is J-Braid X4 right for your setup?

J-Braid X4 is a four-strand option for a low-stretch braid main line. Choose the strength for your lure, cover and reel rather than simply picking the thinnest available size. If you use a leader, select it for the fishing conditions; use backing beneath the braid when the working length you need is shorter than the reel's full capacity.

Your line. Your reel.

How much J-Braid X4 will fit?

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Calculated estimates, not measured fills. Stop at the reel manufacturer's fill level even if some line remains.

Real-World Spooling Test

See Daiwa J-Braid X4 20 lb spooled on the Daiwa BG LT 3000D-XH, with measured yardage and photos of the fill level. This test covers the listed strength, not every size of this line.

Daiwa BG LT 3000D-XH Real-World Line Capacity Test

The numbers behind the setup

Daiwa J-Braid X4 diameter chart

US Dark Green product codes only. Published inch/mm pairs retained. The conflicting 6lb pair is excluded; 150/300/3000-yard lengths are verified by exact row.

Listed diameters and offered spool lengths. Retail stock varies.
Inches	mm	Spools (yd)
0.005	0.130	150, 300, 3000
0.007	0.170	150, 300, 3000
0.008	0.190	150, 300, 3000
0.008	0.210	150, 300, 3000
0.010	0.250	150, 300, 3000
0.011	0.290	150, 300, 3000
0.013	0.330	150, 300, 3000
0.014	0.360	150, 300, 3000
0.017	0.420	150, 300, 3000

Choosing your setup

Choosing your J-Braid X4 strength

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.

Want a guided recommendation?

Continue in the Setup Wizard

Compare actual diameters

Same pound test, different diameters

At your selected strength

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What changes with another line?

Compare with

Select a replacement line to compare.

Nearby diameters in the line database

Line	Strength	Inches	Difference
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At the spooling bench

Backing, working line & leaders

Read the package length

The verified Dark Green product codes 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.

Prepare the spool attachment

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.

Inspect after high load

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.

Calculated examples

How Much Fits on These Reels?

Estimated full-spool capacity for the J-Braid X4 strength selected above, with no backing. These are calculated examples, not physical tests or recommendations for every pairing.

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J-Braid X4 questions, answered

Can I use the X8 chart for X4?

No. At 10 lb, the verified X4 diameter is .17 mm; another J-Braid model is not interchangeable evidence.

Is 6 lb unavailable?

The official page lists it. It is withheld here because its published inch/mm pair conflicts, not because stock availability was established.

Are capacity results measured?

No. They use listed diameters and reel capacity references. Winding tension, line shape, and fill level affect the actual result.

Specifications & sources

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.

Daiwa official product evidence 1 Exact model identity and manufacturer specifications; reviewed 2026-09-13.
Daiwa official product evidence 2 Supporting specification, package or chart evidence; see source note for scope.