# Rear brake disc thickness — minimum (NA6)

Canonical URL: https://miatatorque.com/spec/rear-disc-minimum-thickness-na6/

Applicability: NA 1990–1993 (B6) — Other years inferred from 1990 factory evidence.

Confidence: fsm

Minimum: 7.0 mm (0.28 in)

Always confirm against your factory manual. Match every restriction and follow all stages and procedure notes. Disputed claims must not be automatically resolved. The complete record below preserves every printed unit, source claim and procedure.

```json
{
  "id": "rear-disc-minimum-thickness-na6",
  "name": "Rear brake disc thickness — minimum (NA6)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "note": "Other years inferred from 1990 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "Minimum: 7.0 mm (0.28 in)",
  "procedure": {
    "notes": "Minimum service thickness for original NA6 brake hardware; does not apply to a later brake conversion and is not an after-machining specification."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "P–24 (PDF p. 471)",
      "as_printed": "Minimum: 7.0mm (0.28 in)",
      "verified_years": [
        1990,
        1990
      ],
      "document": {
        "id": "fsm-1990",
        "tier": 1,
        "title": "1990 Mazda MX-5 Miata Workshop Manual",
        "part_number": "1193-10-89C",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1990,
              1990
            ],
            "engines": [
              "B6"
            ]
          }
        ],
        "url": "https://archive.org/details/1990-mazda-mx-5-miata-workshop-manual_202411"
      }
    }
  ],
  "jobs": [],
  "system": "brakes",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/rear-disc-minimum-thickness-na6/"
}
```