Shimano Mastiff FC Fluorocarbon
Diameter chart, reel capacity & backing guide
Mastiff FC is Shimano's NANOARMOR fluorocarbon main line. This guide covers the 90-meter version listed by Shimano Brazil, not the US 200-yard packages. Compare its diameter with your reel capacity and plan a working length with enough reserve before adding backing.
- Construction
- 100% fluorocarbon with NANOARMOR surface structure
- Listed strengths
- 4-20 lb
- Line type
- Fluorocarbon main line
Is Mastiff FC right for your setup?
Mastiff FC is a fluorocarbon main-line option with Shimano's NANOARMOR surface structure. The 90-meter package covered here needs a deliberate working-length plan: check that it leaves enough line for your casts, fish runs and retying. Use backing beneath that working section if the reel holds more, or choose a longer supply when the fishing requires it.
How much Mastiff FC will fit?
Calculated estimates, not measured fills. Stop at the reel manufacturer's fill level even if some line remains.
Shimano Mastiff FC diameter chart
Shimano pt-BR MASTIFF FC 90m. Exact numeric product code/japanAdminCode values from the product table. Inch diameter and yard length converted from metric data.
| Strength | Inches | mm | Spools (m / yd) |
|---|---|---|---|
| 0.006496 | 0.165 | 90 m (about 98.43 yd) | |
| 0.007283 | 0.185 | 90 m (about 98.43 yd) | |
| 0.008071 | 0.205 | 90 m (about 98.43 yd) | |
| 0.009252 | 0.235 | 90 m (about 98.43 yd) | |
| 0.010236 | 0.260 | 90 m (about 98.43 yd) | |
| 0.01122 | 0.285 | 90 m (about 98.43 yd) | |
| 0.012205 | 0.310 | 90 m (about 98.43 yd) | |
| 0.012992 | 0.330 | 90 m (about 98.43 yd) | |
| 0.01378 | 0.350 | 90 m (about 98.43 yd) | |
| 0.014567 | 0.370 | 90 m (about 98.43 yd) |
Choosing your Mastiff FC strength
The exact 5 lb diameter is .185 mm, and 6 lb is .205 mm. Those product-specific numbers should not be replaced with retailer values rounded to two decimal places.
The 10 lb entry is .260 mm and 16 lb is .330 mm. Choose the appropriate tackle first, then recalculate capacity as diameter increases.
The 6 lb strength is verified under numeric product code/japanAdminCode 868572 even though it was absent from the starting catalog inventory. It gets its own strength ID, not the existing 5 lb ID.
Specification-based guidance, not a hands-on Mastiff FC test. Capacity results are estimates, not measured fills.
Want a guided recommendation?
Continue in the Setup WizardSame pound test, different diameters
At your selected strength
Loading diameter comparisons...
What changes with another line?
Nearby diameters in the line database
| Line | Strength | Inches | Difference |
|---|---|---|---|
| Loading line database... | |||
Backing, working line & leaders
90 meters is not 200 yards
A 90-meter package contains about 98.43 yards. This page does not present a US 200-yard package as an interchangeable size for the same regional product code.
Keep knots below the working section
With less than 100 yards in the retail package, assess casting distance, runs, and future trimming before winding the entire package over backing.
Check FC, 90m and product code
The product is fluorocarbon despite the site's broad URL category. Match the package identity and order code, not a category name or similar family label.
How Much Fits on These Reels?
Estimated full-spool capacity for the Mastiff FC strength selected above, with no backing. These are calculated examples, not physical tests or recommendations for every pairing.
Loading capacity estimates...
Mastiff FC questions, answered
Does this verify US Mastiff filler spools?
No. The verified source here is the Shimano pt-BR MASTIFF FC 90m table. US 200-yard stock requires its own exact product code evidence.
Are these inch values official?
The manufacturer table supplies millimeters. Inch values are calculated conversions, clearly marked as such.
Does NANOARMOR make any knot reliable?
No. It is Shimano's surface-structure technology, not a replacement for a suitable knot, careful tying, inspection, and an appropriate drag setting.
Specifications & sources
Checked 2026-09-13. Official product table verifies ten 4-20lb strengths. This config deliberately excludes unverified US 200yd package claims and does not convert kilogram average strength into new pound labels.
Calculations use the catalog's listed inch diameters. Published inch and millimeter values may differ slightly because of rounding.
- Shimano official product evidence 1 Exact model identity and manufacturer specifications; reviewed 2026-09-13.