ISO 10317:2008

Overview - ISO 10317:2008 (Tapered roller bearings designation system)

ISO 10317:2008 defines a standardized designation system for metric tapered roller bearings manufactured in accordance with ISO 355. The standard covers designation formats for complete single-row and double-row bearings, bearings with flanged outer rings, and separate bearing subunits (inner subunit = inner ring, tapered rollers and cage; outer ring). ISO 10317:2008 applies only to bearings and parts that conform to ISO 355.

Key topics and requirements

• Designation structure: A multi-section code made up of groups of alphabetical and/or numerical symbols (sections 1–6). Each section identifies a specific attribute of the bearing.
• Subunit prefixes (section 1):
  • none = complete bearing
  • R = inner subunit (inner ring, rollers and cage)
  • L = outer ring
• Tapered roller designator (section 2): The letter T may be used optionally to indicate tapered roller bearings.
• Dimension series (section 3): Three-symbol series designation as defined in ISO 355 (dimension series links to bearing boundary dimensions).
• Bore size (section 4): Three numerals indicating nominal bore diameter in millimetres (leading zero for bores < 100 mm).
• Design variants (section 5): One to three letters specify variants such as flanged outer rings and a range of double-row or spacer configurations (examples in the standard include symbols like R, D, DZ, DZU, DB, DBU).
• Tolerance class (section 6): Optional suffix up to four symbols to indicate tolerance classes other than normal - e.g. /P6X, /P5, /P4, /P2 (the “/” may be omitted).
• Marking: Marking bearings with ISO 10317 designations is optional.

Example designations from the standard:

• T3CC020 - single-row, normal tolerance
• T3CC020/P6X - single-row, tolerance class 6X
• LT3CC020R - separate flanged outer ring

Applications and users

ISO 10317:2008 is practical for:

• Bearing manufacturers - consistent product identification and cataloguing
• Design and mechanical engineers - unambiguous selection of tapered roller bearings for assemblies
• Procurement and inventory teams - standardized ordering and stock control
• Quality assurance and inspection - matching parts to dimension and tolerance specifications
• Maintenance and service organizations - identifying replacement inner/outer subunits

Related standards

• ISO 355:2007 - Rolling bearings - Tapered roller bearings - Boundary dimensions and series designations (essential for section 3)
• ISO 492 - Rolling bearings - Radial bearings - Tolerances (tolerance classes referenced)
• ISO 5593 - Rolling bearings - Vocabulary (terms and definitions)

Keywords: ISO 10317:2008, tapered roller bearings, designation system, ISO 355, bearing designation, bore size, dimension series, tolerance class, inner subunit, outer ring.