3900 Bearing Size Chart: Thin Double Row Angular Contact Bearings

Double-row series at a 25 mm bore

The same 25 mm bore is available in six double-row series. The cross-section height is (D − d) / 2. A larger section and width carry more load and need more space.

Model	Series	d	D	B	Section height
3805	3800	25	37	10	6
3905	3900	25	42	13	8.5
3005	3000	25	47	16	11
3205	3200 / 5200	25	52	20.6	13.5
4205	4200	25	52	18	13.5
3305	3300 / 5300	25	62	25.4	18.5

How 3800 and 3900 numbers are built

Number or suffix	Meaning	Example
38xx	Thinner double-row series.	3805 = 25 × 37 × 10
39xx	A separate series, thicker than 38xx at the same bore. It is not another name for 3800.	3905 = 25 × 42 × 13
Bore code	00 = 10 mm, 01 = 12 mm, 02 = 15 mm, 03 = 17 mm, 04 and up = code × 5 mm	3810 = 50 × 65 × 12
ZZ or 2Z / 2RS	Metal shields / rubber seals on both sides	3805ZZ, 3005-2Z, 3805-2RS
C3	Internal clearance larger than normal	3006-2RS-C3

3900 series size chart

Each row is one size and links to its model page, where load ratings and drawings are given. Dimensions are in millimetres.

3900 series

d	D	B	Models
10	22	10	3900
12	24	10	3901
15	28	10	3902
17	30	10	3903
20	37	13	3904
25	42	13	3905
30	47	13	3906
35	55	15	3907
40	62	16	3908
45	68	16	3909
50	72	16	3910
55	80	19	3911

Dimensions are the same as on each model page. ZZ and 2RS versions are available for these sizes; see each model page.

Selection checks for double-row bearings

A thin ring takes the shape of its seat. Check shaft and housing roundness, not only diameter.
The axial clearance or preload is set when the bearing is made. State it as a measured value with the test load.
A tight fit reduces the clearance more on thin rings. Choose the fits and the clearance together.
A 3805 has the same bore and OD as a 6805 but is 10 mm wide instead of 7 mm. Check the axial space before you swap them.

Custom thin double-row bearings

We also make thin double-row bearings to drawing: special bores, widths, seals and clearance. Send d, D, B, seal type, clearance, speed, loads and quantity.

Frequently asked questions

What are the dimensions of a 3905 bearing?

A 3905 bearing is 25 × 42 × 13 mm (bore × OD × width).

What is the difference between 3800 and 3900 bearings?

They are two separate series. At the same bore a 3900 bearing has a larger OD and width, so it carries more load. A 3805 is 25 × 37 × 10 mm; a 3905 is 25 × 42 × 13 mm.

Should I choose 2RS or ZZ?

2RS rubber seals keep out more dirt and water. ZZ metal shields run with lower friction. Choose by contamination and speed.

3800 series size chart →30/x, 3000, 3800 and 3900 in one table →Custom miniature double row bearings: one instead of two →Thin-section deep groove bearings 6700, 6800, 6900 →Double-row angular contact bearing series guide →Double-row bearing or a pair of single-row bearings →2RS or ZZ on double-row bearings →Thin-section bearings for robot joints →All double-row angular contact bearings →

3900 Series Double Row Angular Contact Bearings