Bearing data

Dimension
standards
  • (R)NA 22 designs
    ISO 15:2011, dimension series 22, except for the outer ring width
  • NATR, NATV, NUTR .. A, PWTR designs
    ISO 7063:2003 and ANSI/ABMA Standard 18.1-1982 (where standardized)
  • (R)STO
    Not standardized
Profile of the outer ring running surface
  • (R)STO, (R)NA 22, NATR, NATV designs
    Radius = 500 mm
  • NNTR design
    D ≤ 260 mm → Radius = 10 000 mm
    D ≥ 290 mm → Radius = 15 000 mm
  • NATR .. PPA, NATV .. PPA, NUTR .. A, PWTR designs
    Improved crowned profile for better load distribution, higher stiffness and reduced wear
Tolerances

For additional
information
(→ Tolerances)

Normal, except:

  • diameter of the crowned running surface, NNTR design: h10
  • diameter of the crowned running surface, other designs: 0/–0,05 mm
  • width B, NNTR design: 0/–0,5 mm
  • width B, NATR, NATV, NUTR .. A, PWTR designs: h12
  • inside diameter Fw, RSTO, RNA 22 designs: F6

Values for Normal tolerance class: ISO 492:2014 (table 1).

Values for ISO tolerance classes h7, h9, h10, h12 and F6: table 2

Internal clearance
  • STO and NA 22 designs
    Normal
  • Other designs
    Between C2 and Normal

Values: ISO 5753-1:2009: table 3
Values are valid for unmounted bearings under zero measuring load.
Defect frequencies
Defect frequencies can be calculated using the tools available at SKF Bearing Calculator 
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