Deep groove ball bearings are the most widely used bearing type in electric motors, pumps, fans, gearboxes, appliances and automotive parts. This guide gives you the bore, outside diameter and width for the most common metric series, the imperial R-series and double row types, so you can check a size in seconds and avoid ordering the wrong part.
All tables below list the boundary dimensions: d is the bore (inner diameter), D is the outside diameter and B is the width, all in millimeters. The dimensions follow ISO 15, so bearings of the same number from different manufacturers are interchangeable in size.
The 6000 series has the smallest outside diameter and width for a given bore. Choose it when radial space is tight and loads are moderate.
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 6000 | 10 | 26 | 8 |
| 6001 | 12 | 28 | 8 |
| 6002 | 15 | 32 | 9 |
| 6003 | 17 | 35 | 10 |
| 6004 | 20 | 42 | 12 |
| 6005 | 25 | 47 | 12 |
| 6006 | 30 | 55 | 13 |
| 6007 | 35 | 62 | 14 |
| 6008 | 40 | 68 | 15 |
| 6009 | 45 | 75 | 16 |
| 6010 | 50 | 80 | 16 |
| 6011 | 55 | 90 | 18 |
| 6012 | 60 | 95 | 18 |
| 6013 | 65 | 100 | 18 |
| 6014 | 70 | 110 | 20 |
| 6015 | 75 | 115 | 20 |
| 6016 | 80 | 125 | 22 |
| 6017 | 85 | 130 | 22 |
| 6018 | 90 | 140 | 24 |
| 6020 | 100 | 150 | 24 |
The 6200 series is the most common choice for general industrial use. It offers a good balance between load capacity, speed and size. The 6205 and 6206 are among the most frequently ordered bearings in the world.
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 6200 | 10 | 30 | 9 |
| 6201 | 12 | 32 | 10 |
| 6202 | 15 | 35 | 11 |
| 6203 | 17 | 40 | 12 |
| 6204 | 20 | 47 | 14 |
| 6205 | 25 | 52 | 15 |
| 6206 | 30 | 62 | 16 |
| 6207 | 35 | 72 | 17 |
| 6208 | 40 | 80 | 18 |
| 6209 | 45 | 85 | 19 |
| 6210 | 50 | 90 | 20 |
| 6211 | 55 | 100 | 21 |
| 6212 | 60 | 110 | 22 |
| 6213 | 65 | 120 | 23 |
| 6214 | 70 | 125 | 24 |
| 6215 | 75 | 130 | 25 |
| 6216 | 80 | 140 | 26 |
| 6217 | 85 | 150 | 28 |
| 6218 | 90 | 160 | 30 |
| 6220 | 100 | 180 | 34 |
For the same bore, the 6300 series has a larger outside diameter and wider body than the 6200 series, with bigger balls and higher load capacity. It suits shock loads and heavier duty.
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 6300 | 10 | 35 | 11 |
| 6301 | 12 | 37 | 12 |
| 6302 | 15 | 42 | 13 |
| 6303 | 17 | 47 | 14 |
| 6304 | 20 | 52 | 15 |
| 6305 | 25 | 62 | 17 |
| 6306 | 30 | 72 | 19 |
| 6307 | 35 | 80 | 21 |
| 6308 | 40 | 90 | 23 |
| 6309 | 45 | 100 | 25 |
| 6310 | 50 | 110 | 27 |
| 6311 | 55 | 120 | 29 |
| 6312 | 60 | 130 | 31 |
| 6313 | 65 | 140 | 33 |
| 6314 | 70 | 150 | 35 |
| 6315 | 75 | 160 | 37 |
| 6316 | 80 | 170 | 39 |
The 6400 series is the heaviest standard series and is used where high radial load and shock are expected, such as in heavy machinery. It starts at 17 mm bore.
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 6403 | 17 | 62 | 17 |
| 6404 | 20 | 72 | 19 |
| 6405 | 25 | 80 | 21 |
| 6406 | 30 | 90 | 23 |
| 6407 | 35 | 100 | 25 |
| 6408 | 40 | 110 | 27 |
| 6409 | 45 | 120 | 29 |
| 6410 | 50 | 130 | 31 |
| 6411 | 55 | 140 | 33 |
| 6412 | 60 | 150 | 35 |
Miniature bearings have a bore of 9 mm or less. They are common in small motors, instruments, fans, toys and precision devices. Note that the last digit of these numbers is the bore in mm.
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 604 | 4 | 12 | 4 |
| 605 | 5 | 14 | 5 |
| 606 | 6 | 17 | 6 |
| 607 | 7 | 19 | 6 |
| 608 | 8 | 22 | 7 |
| 609 | 9 | 24 | 7 |
| 623 | 3 | 10 | 4 |
| 624 | 4 | 13 | 5 |
| 625 | 5 | 16 | 5 |
| 626 | 6 | 19 | 6 |
| 627 | 7 | 22 | 7 |
| 628 | 8 | 24 | 8 |
| 629 | 9 | 26 | 8 |
Imperial deep groove ball bearings use the R-series (for example R6, R8, R12). They are common in North American equipment, older machinery, agricultural machines and some power tools. The number after the R is the bore in sixteenths of an inch, so R8 has a bore of 8/16 in = 1/2 in.
| Bearing No. | Bore d (in) | OD D (in) | Width B (in) | d × D × B (mm) |
|---|---|---|---|---|
| R2 | 1/8 (0.1250) | 3/8 (0.3750) | 5/32 (0.1562) | 3.175 × 9.525 × 3.967 |
| R4 | 1/4 (0.2500) | 5/8 (0.6250) | 0.1960 | 6.350 × 15.875 × 4.978 |
| R6 | 3/8 (0.3750) | 7/8 (0.8750) | 9/32 (0.2812) | 9.525 × 22.225 × 7.142 |
| R8 | 1/2 (0.5000) | 1-1/8 (1.1250) | 5/16 (0.3125) | 12.700 × 28.575 × 7.938 |
| R10 | 5/8 (0.6250) | 1-3/8 (1.3750) | 11/32 (0.3438) | 15.875 × 34.925 × 8.731 |
| R12 | 3/4 (0.7500) | 1-5/8 (1.6250) | 3/8 (0.3750) | 19.050 × 41.275 × 9.525 |
| R14 | 7/8 (0.8750) | 1-7/8 (1.8750) | 7/16 (0.4375) | 22.225 × 47.625 × 11.113 |
| R16 | 1 (1.0000) | 2 (2.0000) | 1/2 (0.5000) | 25.400 × 50.800 × 12.700 |
| R18 | 1-1/8 (1.1250) | 2-1/8 (2.1250) | 1/2 (0.5000) | 28.575 × 53.975 × 12.700 |
| R20 | 1-1/4 (1.2500) | 2-1/4 (2.2500) | 1/2 (0.5000) | 31.750 × 57.150 × 12.700 |
| R24 | 1-1/2 (1.5000) | 2-3/4 (2.7500) | 5/8 (0.6250) | 38.100 × 69.850 × 15.875 |
A double row deep groove ball bearing has two rows of balls in one bearing. It carries higher radial load than a single row bearing of the same bore and outside diameter, and it gives better stiffness against tilting. It is wider, so it does not always fit in the same housing. The common metric series are the 4200 (light) and the 4300 (medium).
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 4200 | 10 | 30 | 14 |
| 4201 | 12 | 32 | 14 |
| 4202 | 15 | 35 | 14 |
| 4203 | 17 | 40 | 16 |
| 4204 | 20 | 47 | 18 |
| 4205 | 25 | 52 | 18 |
| 4206 | 30 | 62 | 20 |
| 4207 | 35 | 72 | 23 |
| 4208 | 40 | 80 | 23 |
| 4209 | 45 | 85 | 23 |
| 4210 | 50 | 90 | 23 |
| Bearing No. | d (bore) | D (OD) | B (width) |
|---|---|---|---|
| 4300 | 10 | 35 | 17 |
| 4301 | 12 | 37 | 17 |
| 4302 | 15 | 42 | 17 |
| 4303 | 17 | 47 | 19 |
| 4304 | 20 | 52 | 21 |
| 4305 | 25 | 62 | 24 |
| 4306 | 30 | 72 | 27 |
| 4307 | 35 | 80 | 31 |
| 4308 | 40 | 90 | 33 |
| Item | Single Row (e.g. 6205) | Double Row (e.g. 4205) |
|---|---|---|
| Size (d × D × B) | 25 × 52 × 15 mm | 25 × 52 × 18 mm |
| Radial load capacity | Good | Higher |
| Stiffness against tilting | Standard | Better |
| Speed limit | Higher | Lower |
| Friction and heat | Lower | Higher |
| Cost and availability | Lower cost, widely stocked | Higher cost, fewer variants |
| Typical use | Motors, pumps, fans, appliances | Heavy radial load, limited axial space |
To convert millimeters to inches, divide by 25.4. The table below covers the bore sizes used most often.
| Millimeters | Inches (decimal) | Millimeters | Inches (decimal) |
|---|---|---|---|
| 10 mm | 0.3937 in | 40 mm | 1.5748 in |
| 12 mm | 0.4724 in | 45 mm | 1.7717 in |
| 15 mm | 0.5906 in | 50 mm | 1.9685 in |
| 17 mm | 0.6693 in | 60 mm | 2.3622 in |
| 20 mm | 0.7874 in | 80 mm | 3.1496 in |
| 25 mm | 0.9843 in | 100 mm | 3.9370 in |
| 30 mm | 1.1811 in | ||
| 35 mm | 1.3780 in |
Common mistakes to avoid:
Sealing. An open bearing has the lowest friction and needs external lubrication and protection. A ZZ bearing has metal shields that do not touch the inner ring, giving low friction and moderate dust protection. A 2RS bearing has contact rubber seals, giving better protection against dust and moisture but more friction and a lower speed limit.
Radial internal clearance. Clearance is the small free movement inside the bearing before it is mounted. The values below are for bores from 24 to 30 mm, such as the 6205.
| Code | Clearance (µm) | Typical use |
|---|---|---|
| C2 | 0 – 10 | Precision, low noise, light-load applications |
| CN (normal) | 5 – 20 | General applications |
| C3 | 13 – 28 | Interference fits, higher operating temperature, electric motors |
| C4 | 20 – 36 | Large temperature difference between inner and outer rings, heavy interference fits |
Precision grade. P0 is the normal grade and works for most uses. P6 and P5 have tighter tolerances for high-speed or low-vibration equipment such as machine tool spindles and precision motors.
A 6205 bearing has a 25 mm bore, a 52 mm outside diameter and a 15 mm width (0.9843 × 2.0472 × 0.5906 in).
Take 6205-2RS C3 as an example. 6 is the type (single row deep groove), 2 is the light dimension series, 05 is the bore code (05 × 5 = 25 mm), 2RS means rubber seals on both sides, and C3 means internal clearance larger than normal.
ZZ has non-contact metal shields, so friction is lower and speed can be higher, but it protects less against moisture. 2RS has contact rubber seals, so it protects better against dust and water, but friction is higher and the speed limit is lower. The dimensions are the same.
Only if the housing and shaft allow the extra width. For example, a 6205 is 15 mm wide and a 4205 is 18 mm wide, with the same bore and OD. Check the shoulder positions, retaining rings and covers before switching.
Divide the size in millimeters by 25.4. For example, 25 mm ÷ 25.4 = 0.9843 in. Remember that a converted metric size is not the same as an imperial bearing, so the two cannot replace each other.
C3 is a radial internal clearance larger than normal (CN). It leaves room for the reduction in clearance caused by tight fits and heat expansion, and is widely used in electric motors and other equipment that runs warm.
We supply deep groove ball bearings in metric, imperial, single row and double row types, in open, ZZ and 2RS versions, with CN, C3 and other clearance options. OEM branding, special packaging and non-standard dimensions are available for volume orders. We can provide datasheets and CAD drawings on request.
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