| Item # | d | D | B | r | Static Load Rating | Dynamic Load Rating |
| 6821 | 4.1339 in 105.000 mm |
5.1181 in 130.000 mm |
0.5118 in 13.000 mm |
0.0394 in 1.000 mm |
4940 lbf 22000 N 22.00 kN |
4940 lbf 22000 N 22.00 kN |
1. Design features and characteristics
Deep groove ball bearings are very widely used. A deep groove is formed on the inner and outer ring of the bearing enabling the bearing to sustain radial and axial loads in either direction as well as the complex loads which result from the combination of these forces. Deep groove ball bearings are suitable for high speed applications. When two or more deep groove ball bearings are used in combination and mounted adjacent to each other a duplex set (D2) should be used. Duplex bearings (D2) utilize controlled tolerances to more evenly distribute the loading between the individual bearing rows which improves the overall performance of the assembly. In addition to unsealed and unlubricated “open” bearings, NTN provides deep groove ball bearings that are pre-lubricated with grease and enclosed by seals or shields. See section “11. Lubrication” for a list of some of the greases which can be used. Table 1 shows the construction and special characteristics of various sealed deep groove ball bearings.
| Types and codes N | Shielded type | Shielded type | ||
| Non-contact type ZZ | Non-contact type LLB | Contact type LLU | Low torque type LLH | |
| Construction |  |
 |
 |
 |
| Metal shield plate is affixed to the outside ring; the inner ring incorporates a V-groove and labyrinth clearance. | The outer ring incorporates synthetic rubber molded to a steel plate; seal edge is aligned with V-groove along inner ring surface with labyrinth clearance | The outer ring incorporates synthetic rubber molded to a steel plate; seal edge contacts V-groove along inner ring surface | Basic construction is the same as LLU type, but a specially designed lip on the edge of the seal prevents foreign matter penetration; low torque construction. | |
| Torque | Small | Small | Higher | Medium |
| Dust proofing | Good | Better than ZZ-type | Excellent | Much better than LLB-type |
| Water proofing | Poor | Poor | Very good | Good |
| High speed capacity | Same as open type | Same as open type | Limited by contact seals | Much better than LLU-type |
| Allowable temp. range | Depends on lubricant | −25 to 120°C | −25 to 110°C | −25 to 120°C |
