Reference

Radial internal clearance chart.

Unmounted radial clearance for deep groove ball bearings with cylindrical bore, aligned with ISO 5753-1:2009 and GB/T 4604.1.

Values are theoretical ranges at zero measuring load, before mounting.

The measuring load specified in GB/T 25769 / ISO 5753-1 deforms the rings; readings must be corrected back to the zero-load table.

Interference fits, temperature differences and preload change the operating clearance — specify the group for the operating condition, not the catalogue default.

For motor bearings, CN (normal) is common; C3 is used where fits or temperature reduce clearance. Confirm with the application engineer.

Clearance by bore size (µm)
Bore d (mm)	C2	CN	C3	C4	C5
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

Source: ISO 5753-1:2009 Table 1 / GB/T 4604.1 · 未安装、表定值（零测量负荷下的理论游隙范围）

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