Inch Ball Bearings Size Chart: R, 1600, RW, RLS and RMS Series

Same 1/2 in bore, four series

At a 12.7 mm (1/2 in) bore the inch series give four outside diameters and widths. The section height is (D − d) / 2.

Model	Series	d	D	B	Section height
R8	R	12.7	28.575	6.35	7.9375
1616	1600	12.7	28.575	9.525	7.9375
RLS4	RLS	12.7	33.35	9.525	10.325
RMS4	RMS	12.7	41.275	15.875	14.2875

How inch bearing numbers are built

Number or suffix	Meaning	Example
R2 to R24	Number = bore in sixteenths of an inch. R8 = 8/16 in = 12.7 mm.	R8 = 12.7 × 28.575 × 6.35
R1-4, R133, R144, R188 …	Miniature inch sizes	R188 = 6.35 × 12.7 × 3.175
16xx	1600 series: inch bore, wider ring than an R bearing	1616 = 12.7 × 28.575 × 9.525
RWxx	Inch miniature size with an extended inner ring. The inner ring sticks out 1/64 in (0.397 mm) on each side, so it is 1/32 in (0.794 mm) wider than the outer ring. The table gives the outer ring width B.	RW188 = 6.35 × 12.7 × 3.175, inner ring 3.969
RLS / RMS	Inch light series / inch medium series, mostly used as replacements in British machinery	RLS4, RMS4
ZZ / 2RS	Metal shields / rubber seals on both sides	R8ZZ, R8-2RS

Inch bearing size charts

Each row is one size. Open, shielded and sealed versions of the same size are listed together and link to their model pages. Dimensions are in millimetres, converted from inches.

R miniature and small series R8 to R24 1600 series RW series RLS series RMS series

R miniature and small series (bore under 10 mm)

d	D	B	Models
1.016	3.175	1.191	R09
1.191	3.967	1.588	R0
1.191	3.967	2.38	R0 ZZ
1.397	4.762	1.984	R1
1.397	4.762	2.779	R1 ZZ
1.984	6.35	2.38	R1-4
1.984	6.35	3.571	R1-4ZZ
1.985	6.35	3.571	R1-4 2rs
2.3	7.938	2.779	R1-5-2.3 R1-5-2.3 ZZ
2.38	4.762	1.588	R133 R133 ZZ
2.38	4.762	2.38	R133 ZZS R133ZZS
2.38	7.938	2.779	R1-5
2.38	7.938	3.571	R1-5 ZZ
2.381	4.762	2.38	R133 2rs
2.381	7.938	3.571	R1-5 2rs
3.175	6.35	2.38	R144
3.175	6.35	2.779	R144 2rs R144 ZZ
3.175	7.938	2.779	R2-5
3.175	7.938	3.571	R2-5 2rs R2-5 ZZ
3.175	9.525	2.779	R2-6
3.175	9.525	3.571	R2-6 2rs R2-6 ZZ R2-6ZZS
3.175	9.525	3.967	R2 R2 2rs R2 ZZ
3.175	12.7	4.366	R2A R2A 2rs R2A ZZ
3.967	7.938	2.779	R155
3.967	7.938	3.175	R155 ZZ R155ZZS
3.969	7.938	3.175	R155 2rs
4.762	7.938	2.779	R156
4.762	7.938	3.175	R156 2rs R156 ZZ R156ZZS
4.762	9.525	3.175	R166 R166 2rs R166 ZZ
4.762	12.7	4.978	R3 2rs R3 ZZ
4.762	15.875	4.978	R3A 2rs R3Azz
4.763	12.7	3.969	R3
4.763	15.875	4.978	R3A
6.35	9.525	3.175	R168 R168 2rs R168B R168B ZZ R168zz
6.35	12.7	3.175	R188
6.35	12.7	4.762	R188 2rs R188 ZZ
6.35	15.875	4.978	R4 R4 2rs R4B R4B ZZ R4zz
6.35	19.05	5.556	R4A
6.35	19.05	5.558	R4AA
6.35	19.05	7.142	R4A 2rs R4AA ZZ R4Azz
7.938	12.7	3.967	R1810 R1810 2rs R1810 ZZ
9.525	22.225	7.142	R6 2rs R6 ZZ
9.525	22.225	7.144	R6

R8 to R24

d	D	B	Models
12.7	28.575	6.35	R8
12.7	28.575	7.938	R8-2RS R8ZZ
15.875	34.925	7.144	R10
15.875	34.925	8.733	R10-2RS R10ZZ
19.05	41.275	7.938	R12
19.05	41.275	11.112	R12-2RS R12ZZ
22.225	47.625	9.525	R14
22.225	47.625	12.7	R14-2RS R14ZZ
25.4	50.8	9.525	R16
25.4	50.8	12.7	R16-2RS R16ZZ
28.575	53.975	9.525	R18
28.575	53.975	12.7	R18-2RS R18ZZ
31.75	57.15	9.525	R20
31.75	57.15	12.7	R20-2RS R20ZZ
34.925	63.5	11.113	R22
34.925	63.5	14.288	R22-2RS R22ZZ
38.1	66.675	14.288	R24 R24-2RS R24ZZ

1600 series

d	D	B	Models
4.762	17.463	6.35	1601ZZ
6.35	17.463	6.35	1602ZZ
7.938	22.225	7.142	1603ZZ
7.938	23.017	7.938	1605ZZ
9.525	22.225	7.142	1604ZZ
9.525	23.017	7.938	1606 1606ZZ
9.525	28.575	9.525	1614 1614ZZ
11.112	23.017	7.938	1607ZZ
11.112	28.575	9.525	1615ZZ
11.112	34.925	11.112	1620ZZ
11.113	23.017	7.938	1607
11.113	28.575	9.525	1615
11.113	34.925	11.113	1620
12.7	28.575	9.525	1616 1616ZZ
12.7	34.925	11.112	1621ZZ
12.7	34.925	11.113	1621
14.288	34.925	11.112	1622ZZ
14.288	34.925	11.113	1622
15.875	34.925	11.112	1623ZZ
15.875	34.925	11.113	1623
15.875	41.275	12.7	1628 1628ZZ
15.875	44.45	12.7	1633 1633ZZ
19.05	41.275	12.7	1630 1630ZZ
19.05	44.45	12.7	1635 1635ZZ
19.05	50.8	14.288	1638 1638ZZ
20.638	50.8	14.288	1639
22.225	50.8	14.288	1640 1640ZZ
25.4	50.8	14.288	1641 1641ZZ
28.575	63.5	15.875	1652 1652ZZ
31.75	63.5	15.875	1654ZZ
31.75	63.5	16.271	1654
31.75	65.087	17.463	1657ZZ
31.75	65.088	17.642	1657
33.338	65.087	17.463	1658ZZ
33.338	65.088	17.642	1658

RW series

d	D	B	Models
1.191	3.969	1.588	RW0
1.191	3.969	2.38	RW0zz
1.411	4.762	1.984	RW1
1.411	4.762	2.779	RW1zz
1.985	6.35	2.38	RW1-4
1.985	6.35	3.571	RW1-4zz
2.381	4.762	1.588	RW133
2.381	4.762	2.38	RW133zz
2.381	7.938	2.779	RW1-5
2.381	7.938	3.571	RW1-5zz
3.175	6.35	2.38	RW144
3.175	6.35	2.779	RW144zz
3.175	7.938	2.779	RW2-5
3.175	7.938	3.571	RW2-5zz
3.175	9.525	2.779	RW2-6
3.175	9.525	3.571	RW2-6zz
3.175	9.525	3.967	RW2 RW2zz
3.969	7.938	2.779	RW155
3.969	7.938	3.175	RW155zz
4.762	7.938	2.779	RW156
4.762	7.938	3.175	RW156zz
4.762	9.525	3.175	RW166 RW166zz
4.762	12.7	3.967	RW3
4.762	12.7	4.978	RW3zz
6.35	9.525	3.175	RW168 RW168zz
6.35	12.7	3.175	RW188
6.35	12.7	4.762	RW188zz
6.35	15.875	4.978	RW4 RW4zz
7.938	12.7	3.967	RW1810 RW1810zz

RLS series (inch light)

d	D	B	Models
12.7	33.35	9.525	RLS4
15.875	39.7	11.125	RLS5
19.05	47.625	14.3	RLS6
22.225	50.8	14.3	RLS7
25.4	57.15	15.875	RLS8
28.575	63.5	15.875	RLS9
31.75	69.85	17.475	RLS10
34.925	76.2	17.475	RLS11
38.1	82.55	19.05	RLS12

RMS series (inch medium)

d	D	B	Models
12.7	41.275	15.875	RMS4
15.875	46.05	15.875	RMS5
19.05	50.8	17.475	RMS6
22.352	57.15	17.475	RMS7
25.4	63.5	19.05	RMS8
28.702	71.45	20.65	RMS9
31.75	79.375	22.225	RMS10

Dimensions are the same as on each model page. Some shielded or sealed versions are wider than the open bearing, so they have their own row. Flanged inch bearings (FR) are on the flanged bearings page.

Checks when replacing an inch bearing

Measure the bore, outside diameter and width, and convert from inches before comparing. 1/2 in is 12.7 mm, not 12 or 13 mm.
Do not fit a metric bearing on an inch shaft. A small size difference becomes a loose fit or a tight press.
Check whether the old bearing was shielded or sealed. Some ZZ and 2RS versions are wider than the open bearing.
If the old number is worn off, send the three dimensions and a photo. We match the size from the table.

Custom inch bearings

We make non-catalog inch sizes, flanged versions and special seals to drawing. Send d, D and B in inches or millimetres, the closure type, speed and quantity.

Frequently asked questions

What size is an R8 bearing?

An R8 bearing is 1/2 in bore × 1-1/8 in outside diameter × 1/4 in wide, which is 12.7 × 28.575 × 6.35 mm. The R8ZZ and R8-2RS are 7.938 mm wide.

Can I use a metric bearing instead of an inch bearing?

Only if all three dimensions match the shaft and housing within the fit tolerance. Most inch sizes have no metric equal, so use the inch bearing.

What is the difference between R and 1600 bearings?

Both are inch bearings. At the same bore a 1600 bearing usually has a wider ring than an R bearing; compare 1616 and R8 in the table above.

What do RLS and RMS mean?

They are the inch light and inch medium series. At a 1/2 in bore, RLS4 is 33.35 mm and RMS4 is 41.275 mm outside diameter.

What is the difference between RW188 and R188?

Both are 6.35 × 12.7 mm with a 3.175 mm outer ring. The RW188 inner ring is 3.969 mm wide and sticks out 0.397 mm on each side. A part pressed against the inner ring then clears the outer ring without a spacer.

Inch bearing size conversion and identification →MR miniature bearings size chart →Flanged miniature bearings, incl. FR inch →6000, 6200, 6300 size chart →All deep groove and miniature bearings →

Inch Ball Bearings: R, 1600, RW, RLS and RMS Size Chart