Bearing Radial Internal Clearance Chart
Radial internal clearance is the small radial movement available between the bearing rings and rolling elements before the bearing is mounted and loaded. Buyers usually compare C2, CN or Normal, C3, C4, and C5 when they are replacing an existing bearing, reviewing a drawing, or preparing an RFQ for a motor, gearbox, pump, fan, conveyor, or machine spindle.
C2 is tighter than normal clearance, CN is the standard reference group, and C3 through C5 provide progressively larger internal clearance. Larger clearance may be needed when fits, operating temperature, or shaft and housing conditions reduce the running clearance after installation. Tighter clearance may be considered only when the application and mounting conditions support it. If the original bearing marking is known, keep that clearance class in the RFQ instead of assuming that CN can replace every application.
For related bearing families, compare CXE Bearing collections for deep groove ball bearings, needle roller bearings, and self-aligning ball bearings before matching the clearance table to a replacement request.
Comprehensive Radial Clearance Tables for CXE Bearing Series
All Clearance Values in Micrometers (μm)
1. Deep Groove Ball Bearings
Table 1: Radial Internal Clearance for Cylindrical Bore Bearings
Bore Diameter d (mm) C2 (Group 2) Normal (Group 0) C3 (Group 3) C4 (Group 4) C5 (Group 5)
Over Up to min max min max min max min max min max
2.5 6 0 7 2 13 8 23 14 29 20 37
6 10 0 7 2 13 8 23 14 29 20 37
10 18 0 9 3 18 11 25 18 33 25 45
18 24 0 10 5 20 13 28 20 36 28 48
24 30 1 11 5 20 13 28 23 41 30 53
30 40 1 11 6 20 15 33 28 46 40 64
40 50 1 11 6 23 18 36 30 51 45 73
50 65 1 15 8 28 23 43 38 61 55 90
65 80 1 15 10 30 25 51 46 71 65 105
80 100 1 18 12 36 30 58 53 84 75 120
100 120 2 20 15 41 36 66 61 97 90 140
120 140 2 23 18 48 41 81 71 114 105 160
140 160 2 23 18 53 46 91 81 130 120 180
160 180 2 25 20 61 53 102 91 147 135 200
180 200 2 30 25 71 63 117 107 163 150 230
2. Self-aligning Ball Bearings
Table 2: Cylindrical Bore Bearings
Bore Diameter d (mm) C2 Normal C3 C4 C5
Over Up to min max min max min max min max min max
2.5 6 1 8 5 15 10 20 15 25 21 33
6 10 2 9 6 17 12 25 19 33 27 42
10 14 2 10 6 19 13 26 21 35 30 48
14 18 3 12 8 21 15 28 23 37 32 50
18 24 4 14 10 23 17 30 25 39 34 52
24 30 5 16 11 24 19 35 29 46 40 58
30 40 6 18 13 29 23 40 34 53 46 66
40 50 6 19 14 31 25 44 37 57 50 71
50 65 7 21 16 36 30 50 45 69 62 88
65 80 8 24 18 40 35 60 54 83 76 108
80 100 9 27 22 48 42 70 64 96 89 124
Table 3: Tapered Bore Bearings
Bore d (mm) C2 Normal C3 C4 C5
Over Up to min max min max min max min max min max
18 24 7 17 13 26 20 33 28 42 37 55
24 30 9 20 15 28 23 39 33 50 44 62
30 40 12 24 19 35 29 46 40 59 52 72
40 50 14 27 22 39 33 52 45 65 58 79
3. Cylindrical & Needle Roller Bearings
Table 4: Radial Internal Clearance for Cylindrical Bore
Bore Diameter d (mm) C2 Normal C3 C4 C5
Over Up to min max min max min max min max min max
0 10 0 25 20 45 35 60 50 75
10 24 0 25 20 45 35 60 50 75 65 90
24 30 0 25 20 45 35 60 50 75 70 95
30 40 5 30 25 50 45 70 60 85 80 105
40 50 5 35 30 60 50 80 70 100 95 125
50 65 10 40 40 70 60 90 80 110 110 140
80 100 15 50 50 85 75 110 105 140 155 190
4. Spherical Roller Bearings
Table 5: Cylindrical Bore Bearings
Bore d (mm) C2 Normal C3 C4 C5
Over Up to min max min max min max min max min max
14 18 10 20 20 35 35 45 45 60 60 75
24 30 15 25 25 40 40 55 55 75 75 95
50 65 20 40 40 65 65 90 90 120 120 150
100 120 40 75 75 120 120 160 160 210 210 260
5. Machine Tool Double-row Roller Bearings
Table A.1: Tapered Bore
Bore Dia. d (mm) Group 1 Group 2
Over Up to min max min max
24 30 15 25 20 30
40 50 17 30 30 45
80 100 35 55 45 70
Table A.2: Cylindrical Bore
Bore Dia. d (mm) Group 1 Group 2
Over Up to min max min max
24 30 5 15 10 25
40 50 5 18 15 30
80 100 10 30 25 45
Selecting the Right Clearance: Internal clearance is the total distance through which one bearing ring can be moved relative to the other in the radial direction (Radial Internal Clearance).
Normal (CN): Best for general applications with standard fits and temperatures.
C3/C4/C5: Used when heavy interference fits are required or when significant temperature gradients exist between the inner and outer rings.
C2: Used when high running accuracy and rigidity are required.
For high-speed spindles or extreme precision requirements, please consult CXE Bearing’s engineering team for specific configuration advice.