BEARINGDEX
Deep groove ball, thin section

6904 bearing

20 mm bore, 37 mm outside diameter, 9 mm width (0.7874 × 1.4567 × 0.3543 in). SKF numbers it 61904.

Cross-reference 6904Decode a full part number

Dimensions

mminch
Bore d200.7874
Outside diameter D371.4567
Width B90.3543

Quick numbers

Pitch diameter dm28.5 mm
Section height (D − d)/28.5 mm
n·dm at 1,800 rpm51,300
n·dm at 3,600 rpm102,600

Compare against the maker's limiting speed. Speed calculator · L10 life

What the number means

6Deep groove ball, thin section
9Diameter series 9: very thin. Width series 0 is implied and left off.
04Bore code 04 × 5 = 20 mm

How each brand writes it

Same bearing, every maker's notation
VersionSKFFAGNSKNTNKoyoNACHI
Open6190469046904690469046904
Shields both sides61904-2Z6904-2ZR6904ZZ6904ZZ6904ZZ6904ZZE
Contact seals both sides61904-2RSH6904-2RSR6904DDU6904LLU6904-2RS6904-2NSE
Contact seals both sides, C361904-2RSH/C36904-2RSR-C36904DDUC36904LLUC36904-2RSC36904-2NSE C3 Verify
Non-contact seals both sides61904-2RSL6904-2BRS Verify6904VV6904LLB6904-2RU Verify6904-2NKE Verify
Shields both sides, C361904-2Z/C36904-2ZR-C36904ZZC36904ZZC36904ZZC36904ZZE C3 Verify