Self-aligning ball bearings: what 1200, 1300, 2200 and 2300 mean, with a size chart

A self-aligning ball bearing has two rows of balls running in one spherical raceway in the outer ring, so the inner ring, balls and shaft can tilt about 2.5 to 3 degrees (open bearings). The number tells you the size: our 1202 is 15 mm bore, 35 mm outside and 11 mm wide, sold in a pack of 10.

Got a 12, 13, 22 or 23 number? This table shows how to read it; the size chart below gives the full sizes of the numbers people search most.

Source: bearing makers' published designation tables and bearing tables (see Sources), read 12 October 2026.

How a self-aligning ball bearing works

The outer ring raceway is part of a sphere centred on the bearing. The inner ring has two raceway grooves, one for each row of balls. So the inner ring, the balls and the cage can swing as one inside the outer ring. That lets the bearing take up a shaft that bends under load, a housing bore that isn't quite in line, or small fitting errors.

How far can it tilt? One bearing maker's catalogue gives 2.5 degrees for open 12 and 22 series bearings, 3 degrees for open 13 and 23 series, and 1.5 degrees for sealed bearings. Some maker documents give larger figures under normal loads, but makers warn that the parts around the bearing may limit the angle. Self-aligning ball bearings also carry only limited axial (end) load; for heavy axial loads makers point to spherical roller bearings instead.

Self-aligning bearing size chart

These are the self-aligning numbers Australians search for most, with the standard boundary dimensions. The "same size as" column shows the 62 series deep groove bearing that has the same bore, OD and width.

Source: bearing makers' self-aligning and deep groove ball bearing tables, our bearing size chart for the 62 series up to 6210, and our product listings, read 12 October 2026.

That "same size as" column is the trap. A bearing that measures 15 x 35 x 11 could be a 1202 or a 6202. Look inside: a self-aligning bearing has two rows of balls and its inner ring tilts in your fingers; a deep groove bearing has one row of balls and its rings stay in line. They're different bearings, so replace like with like and read the number on the old one.

Four things called "self-aligning"

Search for "self-aligning bearing" and you'll find four different parts. Only the first is a 12, 13, 22 or 23 series bearing.

1. Self-aligning ball bearings (12, 13, 22, 23). Two rows of balls, the bearing tilts inside itself. Four-digit numbers such as 1202 or 2204. We list the 1202 in a pack of 10, parallel (cylindrical) bore.
2. Spherical roller bearings (222, 223 and others). Two rows of barrel-shaped rollers in a spherical outer raceway. Their numbers have five digits: 22208 is a spherical roller bearing, 2208 is a self-aligning ball bearing, and both measure 40 x 80 x 23 mm, so go by the number. Spherical roller bearings aren't in our range.
3. Pillow block and flange units. Our UCP, UCF, UCFL and UCT units are titled "self aligning", but they align in the housing, not inside the bearing: the insert's outer surface and the housing bore are both spherical. Our units arrive with the insert fitted, and you may need to align it for your job. Our UCP vs UCF vs UCFL guide explains the housings.
4. Spherical plain bearings and rod ends. A ball swivelling in a ring, with no rolling balls at all. We sell them as rose joints; see our rose joint sizes guide.

Some of our mower and go-kart bearings are listed as self-aligning or sit in our self-aligning collection too. They carry SB numbers (SB205, SB206, SB208, SB210), not 12, 13, 22 or 23 numbers, so match them by the number on the old bearing.

How to choose

1. Read the number on the old bearing. A plain four-digit number starting 12, 13, 22 or 23 (with or without K or 2RS) is a self-aligning ball bearing. Five digits starting 222 or 223 is a spherical roller bearing.
2. Check the suffix. A K means a tapered bore, which needs the matching tapered seat or adapter sleeve; a parallel-bore bearing won't do the same job. 2RS means sealed.
3. No number? Measure bore, OD and width, find them in the chart, then check for two rows of balls so you don't mix up a 12 series and a 62 series bearing.
4. Mounting: follow the machine maker's procedure, or have a mechanic or bearing fitter do it.

Which Bearings Express part fits

• Pick the 1202 self-aligning ball bearings, pack of 10 for a 1202: 15 x 35 x 11 mm, parallel bore.
• Pick the UCP201 to UCP207 pillow block bearings, or the pair of UCP205 25 mm pillow blocks, if what you need is a self-aligning unit that bolts down with the bearing already in its housing.
• Pick the Cox lay shaft self-aligning bearings, BB25SAN or SB205 for the Cox ride-ons that listing names, as the axle bearing.
• Pick the female rod ends if you're after a spherical plain bearing (rose joint).

Our self-aligning collection has the 1202 and our go-kart bearings. Need a 12, 13, 22 or 23 series size we don't list? Send us the number from your old bearing and we'll check.

Questions people also ask

What size is a 1202 bearing?

15 mm bore, 35 mm outside diameter and 11 mm wide. That's the same outside size as a 6202, but a 1202 has two rows of balls and tilts.

What is a 2201 bearing?

A wide self-aligning ball bearing: 12 mm bore, 32 mm OD and 14 mm wide. The 1201 has the same bore and OD at 10 mm wide. Neither is in our range.

What size is a 1208 bearing?

40 mm bore, 80 mm OD and 18 mm wide. A 2208 is the wide version, 23 mm.

Are self-aligning roller bearings the same as self-aligning ball bearings?

No. Self-aligning roller bearings (spherical roller bearings) have barrel-shaped rollers and five-digit numbers like 22208. Self-aligning ball bearings have balls and four-digit numbers like 1208 or 2208.

What is a self-aligning bearing housing?

A pillow block or flange housing with a spherical bore. The insert bearing swivels in it to line up with the shaft. Our UCP, UCF, UCFL and UCT units work this way.

Related reading

• Bearing size chart 6000 to 6310
• UCP vs UCF vs UCFL: pillow block or flange bearing
• Rose joints (rod ends): sizes, male vs female, and left vs right thread

Sources

• NTN, Ball and Roller Bearings, Cat. No. 2203/E, "Self-Aligning Ball Bearings", pp. B-79 to B-87, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_b05.pdf, read 12 October 2026.
• NTN, Ball and Roller Bearings, Cat. No. 2203/E, "Boundary Dimensions and Bearing Number Codes", Table 5.2, pp. A-48 to A-51, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_a05.pdf, read 12 October 2026.
• NTN, Ball and Roller Bearings, Cat. No. 2203/E, "Deep Groove Ball Bearings", pp. B-28 to B-29, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_b02.pdf, read 12 October 2026.
• NTN, Ball and Roller Bearings, Cat. No. 2203/E, "Spherical Roller Bearings", p. B-211, https://www.ntnglobal.com/en/products/catalog/pdf/2203E_b08.pdf, read 12 October 2026.
• NSK, Double Row and Customised Ball Bearings, "Self Aligning Ball Bearings", pp. 8 to 12, https://www.nsk.com/content/dam/nsk/am/en_us/documents/bearings-americas/Double-Row-Ball-Bearings-Cutomized-Ball-Bearings.pdf, read 12 October 2026.
• NSK, Self-Aligning Ball Bearings (product page), https://www.nsk.com/products/ball-bearings/self-aligning-ball-bearings/, read 12 October 2026.

Checked against the bearing makers' catalogues above and Bearings Express product listings on 12 October 2026.