55mm ID Bearings | McMaster-Carr

Smoother than smooth—the balls inside these bearings roll nearly friction-free. You’ll often find them on rapidly rotating parts, from the whirring chuck on a power drill to the spinning shaft on an electric motor.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Shielded—The balls are covered just enough to keep out large particles while allowing air to pass through and dissipate heat.

Sealed—The best choice for dirty environments. A barrier seals out dust so it won't gunk up or wear down the balls. However, these bearings retain the most heat since air can't flow through.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

Corrosion-Resistant 440C Stainless Steel—Combine the strength of steel with the corrosion resistance of stainless steel. These bearings won't degrade from water or mild chemicals, such as the ammonia in cleaning solutions. However, they'll weaken when exposed to salt water and harsh chemicals, such as bleach.

ABEC Rating—Bearings with an ABEC rating meet industry tolerance standards established by the Annular Bearing Engineers Committee (ABEC). They're rated on a scale from 1 to 9. The higher the rating, the tighter the tolerance. Bearings rated ABEC 1 or 3 are precise enough for most applications. If your application consistently runs at high speeds or requires high accuracy, consider bearings rated ABEC 5 or higher, since they generate less friction and heat.

							Temp. Range, ° F
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	Inner Ring Type	Bearing Trade No.		Each
Open







				Steel

				55	72	9	1	1,950	10,000	-50	130	Standard	6811	6656K146	000000


				55	80	13	1	3,700	10,000	-50	130	Standard	6911	6656K147	00000
				55	100	21	1	10,300	9,500	-20	230	Standard	6211	5972K113	00000
				55	120	29	1	17,100	8,500	-20	230	Standard	6311	5972K127	00000


				Shielded







								Steel

								55	72	9	1	1,950	8,700	-40	150	Standard	6811-2Z	6656K234	00000


								55	80	13	1	3,700	8,700	-40	150	Standard	6911-2Z	6656K235	00000
								55	90	18	1	6,700	9,100	-20	230	Standard	6011-2Z	5972K273	000000
								55	90	18	3	6,650	8,000	-20	230	Standard	6011-2Z	4481N21	000000
								55	100	21	3	10,350	7,000	-20	230	Standard	6211-2Z	4481N37	000000
								55	120	29	3	16,650	6,300	-20	230	Standard	6311-2Z	4481N51	000000


								Sealed







												Steel

												55	90	18	1	6,700	4,100	-20	230	Standard	6011-2RS	5972K235	000000


												55	90	18	3	6,650	5,000	-30	210	Standard	6011-2RS	4481N67	000000
												55	100	21	1	9,650	3,900	-20	230	Standard	6211-2RS	5972K53	00000
												55	100	21	3	10,350	4,300	-30	210	Standard	6211-2RS	4481N81	000000
												55	120	29	1	17,100	3,500	-20	230	Standard	6311-2RS	5972K64	00000
												55	120	29	3	16,650	3,800	-30	210	Standard	6311-2RS	4481N91	000000




														Corrosion-Resistant 440C Stainless Steel

														55	90	18	1	6,350	4,200	-20	210	Standard	6011-2RS	6138K114	000000


55														100	21	1	9,750	4,000	-20	210	Standard	6211-2RS	6138K115	000000
55	120													29	1	16,100	3,500	-20	210	Standard	6311-2RS	6138K116	000000

Permanently Lubricated Ball Bearings

Install and forget these self-lubricating bearings. Their lubricant is a solid material that fills the space between the balls and releases oil over time, so you'll never need to add more.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Sealed—The best choice for dirty environments. A barrier seals out dust so it won't gunk up or wear down the balls. However, these bearings retain the most heat since air can't flow through.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

							Temp. Range, ° F
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	Inner Ring Type	Bearing Trade No.		Each
Open







				Steel

				55	100	21	1	7,500	3,700	10	200	Standard	6211	2349K709	0000000


				55	120	29	1	13,100	3,300	10	200	Standard	6311	2349K723	000000


				Sealed







								Steel

								55	90	18	1	4,900	4,000	10	200	Standard	6011-2RS	2349K752	000000


								55	100	21	1	7,500	3,700	10	200	Standard	6211-2RS	2349K764	000000
								55	120	29	1	13,100	3,300	10	200	Standard	6311-2RS	2349K778	000000

Spherical-Roller Bearings

Two rows of rollers give these bearings dynamic radial load capacities over five times higher than comparably sized tapered-roller bearings. Also known as rock crusher bearings, they handle heavy shock loads and are used for metal milling machinery, mining and oil field equipment, and in paper mills.

						Combined Load Cap., lbf
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	Bearing Trade No.	Ring Material	Dynamic	Static	Max. Rotation Speed, rpm	Lubrication	Max. Temp., ° F		Each
Open Bearing



		55	100	25	22211	Steel	33,400	32,300	5,300	Required	390	2721T7	0000000

High-Load Face-Mount Crossed-Roller Bearings

With thicker inner and outer raceways, these bearings can handle heavier loads than thin-profile crossed roller bearings. Mounting holes on the inner and outer rings allow for fastening onto hollow joints and shafts. The rollers face in alternating directions to allow for rigid, accurate motion under any combination of radial, thrust, and moment (twisting) loads. Use in applications where highly accurate motion is necessary, such as machine tools and industrial robots.

Open Bearing—Open bearings dissipate heat more efficiently than sealed bearings.

Sealed Bearing—Sealed bearings block out dust and other contaminants better than open bearings, but retain more heat.

				Combined Load Cap., lbf
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	Dynamic	Static	Max. Rotation Speed, rpm	Lubrication	Temp. Range, ° F	Features		Each
For Combined Radial, Thrust, and Moment Load—Open with Steel Ring



		55	120	15	4,500	6,200	850	Required	0 to 230	Lubrication Groove, Two Lubrication Holes	2010N15	0000000


		For Combined Radial, Thrust, and Moment Load—Sealed with Steel Ring



				55	120	15	4,500	6,200	650	Lubricated	0 to 210	Lubrication Groove, Two Lubrication Holes	2010N25	000000

Self-Aligning Ball Bearings

Open

Misalignments correct themselves on the fly in these bearings. Two rows of balls have separate raceways in the inner ring and a shared raceway in the outer ring, so the balls rock back and forth to compensate for misalignment. This construction also reduces noise and vibration.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

								Temp. Range
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Misalignment Capability	Min.	Max., ° F	Inner Ring Type	Bearing Trade No.		Each
Open







				Steel

				55	100	25	1	6,000	6,000	4°	Not Rated	210	Standard	2211	6660K347	0000000


				55	120	43	1	17,150	4,800	4°	Not Rated	210	Standard	2311	6660K349	000000

High-Precision Angular Contact Ball Bearings

Sealed

Our most precise bearings for tackling radial and thrust loads at once, with tolerances tighter than a speck of dust. Rated ABEC 7 out of 9, they meet strict tolerance standards established by the Annular Bearing Engineers Committee (ABEC). Choose them for equipment that requires both high speed and pinpoint accuracy, such as machine tool spindles. For example, a bearing on a spindle withstands a radial load as it spins at high speeds and a thrust load when the cutting tool touches the workpiece. These bearings don’t handle as much force from radial loads as standard ones, but you can pair them with a cylindrical roller bearing to increase their load capacity.

Single Row—Single-row bearings withstand thrust loads from one direction.

Sealed—The best choice for dirty environments. A barrier seals out dust so it won't gunk up or wear down the balls. However, these bearings retain the most heat since air can't flow through.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

										Temp. Range, ° F
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Material	Dynamic Combined Load Cap., lbf	Max. Rotation Speed, rpm	Lubrication	Contact Angle	Min.	Max.	Bearing Trade No.		Each
Single Row







				Sealed

				55	90	18	7	Steel	8,050	15,900	Lubricated	15°	0	230	7011	4487N16	000000000

Needle-Roller Bearings

Also known as drawn-cup roller bearings, these are our thinnest roller bearings. The outer ring is drawn out to form a lip that holds the bearing together. Bearings take on the shape of their housing and may be oblong prior to installation.

Open Bearing—Open bearings dissipate heat more efficiently than sealed bearings.

				Radial Load Cap., lb.
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	Dynamic	Static	Max. Rotation Speed, rpm	Lubrication	For Shaft Surface Smoothness, Ra, μin	Temp. Range, ° F	Specs. Met		Each
For Radial Load—Open with Steel Ring



		55	63	20	7,050	15,050	4,850	Required	8	-20 to 280	DIN 618, ISO 3245	5905K564	000000

Tapered-Bore Ball Bearings

Mount these bearings on tapered shafts. Or, pair with an adapter sleeve to install them on round shafts without needing to press fit. The two rows of balls have separate raceways in the inner ring and a shared raceway in the outer ring, so the balls rock back and forth to compensate for misalignment. This construction also reduces noise and vibration.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

	Bearings														Adapter Sleeves
									Temp. Range
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Misalignment Capability	Rate of Taper	Min.	Max., ° F	Inner Ring Type	Bearing Trade No.		Each	For Shaft Dia., mm		Each
Open







				Steel

				55	100	25	1	6,000	6,000	4°	1:12	Not Rated	240	Standard	2211K	7755N43	0000000	50	4449N25	000000

Electrically Insulating Ball Bearings

Shielded

Protect bearings from stray currents. The ceramic balls insulate bearings from electrical charges in electric motors and power generators that can damage the inner ring over time. The balls also generate less heat than metal ones, so you don’t have to lubricate them as often to keep bearings running smoothly.

Shielded—The balls are covered just enough to keep out large particles while allowing air to pass through and dissipate heat.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

							Temp. Range, ° F			Ceramic Balls
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	Bearing Trade No.		Each
Shielded







				Steel

				55	100	21	1	11,400	9,600	-20	245	6211-2Z	1389N43	0000000

Mounted Ball Bearings with Four-Bolt Flange

Smoother than smooth—the balls inside these bearings roll nearly friction-free. The four-bolt flange supports shafts with a stronger connection to the mounting surface than two-bolt alternatives.

Lubricate regularly to keep your bearing in tip-top shape. Bearings with seals keep lubricants in and contaminants out, and come packed with grease. Open bearings require initial lubrication and offer less protection against dust and debris.

Powder-Coated Cast Iron Housing—A rugged iron base coated in thick powder that protects against water, mild detergents, and oil. However, if the coating is scratched or chipped, the underlying iron may rust.

Set Screw—Turn the screw to lock your shaft in place. A simple, reliable choice, set screws grip tightly, but they can mar shaft surfaces.

Sealmaster—Famous for exceptional sealing, Sealmaster bearings include a signature three-part seal in the inner ring. This design blocks out gritty debris and purges old grease to extend the life of the bearing.

Misalignment Capability—Bearings compensate for as much shaft misalignment as the degree listed. This extends the life of the bearing and protects against wear if shafts are slightly askew.

		Overall, mm
	For Shaft Dia., mm	Lg.	Wd.	Flange Thk., mm	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Bearing Material	Bearing Seal Type	Misalignment Capability	Manufacturer		Each
Powder-Coated Cast Iron Housing







				Set Screw

				55	161.9	58.7	20.6	9,750	3,200	Steel	Sealed	2°	Sealmaster	1485N8	0000000

Thrust Ball Bearings

For silky-smooth motion, the balls inside these bearings roll nearly friction-free. You'll often find them at the end of a shaft or between a stationary and rotating surface, such as on a propeller or rotary table.

These bearings come as three separate pieces—one cage and two washers. The cage holds the balls in place, while the washers create a surface for the balls to roll on. This design is easy to lubricate, but the oil will attract dust and grime since it's exposed.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

	OD, mm	Thk., mm	Cage Material	Dynamic Thrust Load Cap., lb.	Max. Rotation Speed, rpm	Temp. Range, ° F	Includes		Each
Steel



	55	78	18	Steel	8,900	2,600	-40 to 240	Two Washers	6681K24	0000000


	55	90	25	Steel	15,600	3,000	-40 to 250	Two Washers	7806K763	000000

High-Load Cylindrical-Roller Thrust Bearings

Thick, pop-can-shaped rollers balance strength and speed. These bearings reduce friction and support heavier loads than ball or needle-roller thrust bearings.

They come as three separate pieces—one cage and two washers. The cage holds the rollers in place, while the washers create a surface for the rollers to run on. This design is easy to lubricate, but the oil will attract dust and grime since it’s exposed.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

	OD, mm	Thk., mm	Cage Material	Dynamic Thrust Load Cap., lb.	Max. Rotation Speed, rpm	Temp. Range, ° F	Includes		Each
Steel



	55	78	16	Nylon	20,200	4,350	-25 to 245	Two Washers	4300N21	0000000

Bearing Adapter Sleeves

Make up for imperfections and gaps between your bearing and shaft for a tight fit. These bearing adapter sleeves are the most common way to mount a bearing with a tapered bore onto a cylindrical seat. They work with both straight and stepped shafts. Secure using the included lock nut.

Metric

	For Shaft Dia., mm	ID, mm	Wd., mm	Includes		Each
Low-Carbon Steel



	H 2312	55	55	62	Lock Nut, Lock Washer	7835T161	0000000

Sleeve Bearings

These bearings don’t come with a lubricant, so you can select the oil that meets the needs of your application. You’ll need to refill the oil, so make sure the bearing is located where you can access it. All are fabricated and inspected in the U.S.

With no moving parts, sleeve bearings are the simplest way to support the load of a rotating shaft while reducing friction. Also known as plain bearings.

High-Load 932 Bearing Bronze—These bearings are strong enough for sudden starts and stops, plus they resist wear and tear. They are cast from an alloy of leaded tin bronze for uniform rigidity and strength. Also known as 660 leaded bronze bearings.

	For Housing ID, mm	Lg., mm	Dynamic Radial Load Cap. @ Speed	Temp. Range, ° F		Each
High-Load 932 Bearing Bronze



	55	70	50	17,050 lb. @ 30 rpm	-350 to 450	7811K319	000000


	55	70	75	25,550 lb. @ 30 rpm	-350 to 450	7811K321	00000
	55	70	100	34,100 lb. @ 30 rpm	-350 to 450	7811K318	00000

Corrosion-Resistant Flush-Mount Screw-Clamp Bushings

Insert these nickel-plated steel bushings into the bore of your sprocket for flush or recessed mounting in wet environments. When you tighten the included clamping screws on these bushings, their inner sleeve contracts onto the shaft and their outer sleeve expands to hold your sprocket, pulley, or gear. This keeps bushings from slipping during sudden starts and stops.

	OD, mm	Overall Wd., mm	Max. Torque, in·lbf	Fastener Tightening Torque, in·lbf	Includes		Each
Nickel-Plated Steel



	55	85	32	22,700	360	Clamping Screws	5515N17	0000000

Shims

With thickness tolerances as fine as a strand of hair, these shims precisely align, space, and level components on shafts, arbors, and machinery.

You can stack multiple shims to achieve your exact thickness, but stacking more than four may cause them to shift. Remember, fewer shims are better, so a couple of thicker shims are more stable than a bunch of thin shims.

18-8 Stainless Steel—The choice for wet and outdoor environments, these shims resist rust. However, they’ll corrode or pit when exposed to salt water and chemicals.

Carbon Steel—Best for dry environments since moisture will cause these shims to rust.

Stress-Resistant Spring Steel—These shims are harder and hold their shape better than carbon steel. Use them for high-stress applications, such as leveling heavy machinery. They're best for dry environments since moisture will cause them to rust.

	OD Tolerance, mm	Min. Hardness	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel







	55 mm ID × 68 mm OD

	0.1	-0.013 to 0.013	-0.31 to 0.29	0.02 to 0.12	Rockwell B70	—	5	98089A505	000000


	0.2	-0.023 to 0.023	-0.31 to 0.29	0.02 to 0.12	Rockwell B70	—	5	98089A626	00000
	0.3	-0.055 to 0.055	-0.31 to 0.29	0.02 to 0.12	Rockwell B70	—	5	98089A738	00000
	0.5	-0.064 to 0.064	-0.31 to 0.29	-0.01 to 0.09	Rockwell B70	—	5	98089A850	00000
	1	-0.105 to 0.105	-0.31 to 0.29	0.02 to 0.12	Rockwell B70	—	5	98089A962	00000


	Carbon Steel







					55 mm ID × 68 mm OD

					0.1	-0.013 to 0.013	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	1	3088A017	00000


					0.2	-0.045 to 0.045	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	1	3088A037	00000
					0.3	-0.072 to 0.072	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	1	3088A604	00000
					0.5	-0.064 to 0.064	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	10	3088A077	0000
					1	-0.105 to 0.105	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	10	3088A097	00000
					1.5	-0.14 to 0.14	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	5	3088A117	00000
					2	-0.21 to 0.21	-0.3 to 0.3	-0.5 to 0.5	Rockwell B40	—	5	3088A309	00000


					Stress-Resistant Spring Steel







									55 mm ID × 68 mm OD

									0.2	-0.04 to 0	0.03 to 0.4	-0.47 to -0.04	Rockwell B85	DIN 988	5	98055A444	0000


									0.3	-0.05 to 0	0.03 to 0.4	-0.47 to -0.04	Rockwell B85	DIN 988	5	98055A446	0000
									0.5	-0.05 to 0	0.03 to 0.4	-0.47 to -0.04	Rockwell B85	DIN 988	5	98055A448	0000
									1	-0.05 to 0	0.03 to 0.4	-0.47 to -0.04	Rockwell B85	DIN 988	5	98055A450	0000

Quick-Disconnect (QD) Bushings


Clamp-On Shaft Mount

The screw connections on these bushings easily mate to compatible quick-disconnect sprockets and pulleys. Bushings fit quick-disconnect (QD) sprockets and pulleys of the same bushing trade number. As you tighten the included screws, the bushing grips the shaft and pulls it into the sprocket or pulley.

		Keyway, mm
	Overall Wd., mm	Wd.	Dp.	Fastener Tightening Torque, in·lbf	Material	Includes	For Shaft Dia., mm		Each
Clamp-On Shaft Mount







				Bushing Trade Number SF

				52	16	4.3	360	Sintered Steel	Clamping Screws	55	2344K68	000000




						Bushing Trade Number SK

						49	16	4.3	180	Cast Iron	Clamping Screws	55	2344K52	00000

Flush-Mount Screw-Clamp Bushings

Insert these bushings into the bore of your sprocket for flush or recessed mounting. They handle shock loads. When you tighten the included clamping screws, the bushing's inner sleeve contracts onto the shaft and the outer sleeve expands to hold your sprocket, pulley, or gear. They can be mounted on shafts with or without keyways.

	OD, mm	Overall Wd., mm	Max. Torque, in·lbf	Fastener Tightening Torque, in·lbf	Includes		Each
Steel



	55	85	66	45,100	363	Clamping Screws	1070N18	0000000

Metric Press-Fit Drill Bushings

Also known as jig bushings, these metric drill bushings fit inside fixture plate holes to precisely guide drill bits, counterbores, reamers, and other cutting tools. They improve accuracy so that your drilled holes and cuts are consistent from part to part. Known for their versatility, drill bushings are also used as spacers, shims, and machinery bushings. These bushings are made of hardened, ground steel that holds its shape and resists wear, so they last for many cycles without needing to be replaced.

All bushings have a chamfer on the outside that centers the bushing as you place it into the hole. Press into place with a manual or hydraulic press. Since the bushing is sized slightly larger than the hole for an extremely tight fit, it’ll stay put permanently. These are ANSI Type PM bushings—also known as headless bushings—which means you don’t need to counterbore the hole to mount them flush.

They also have an internal chamfer that makes it easy to insert bits, pins, and punches without damaging the bushing or misaligning tools.

Don't see the size you need? Additional sizes are available.

						Tolerance, mm							Each
	OD, mm	Lg., mm	Internal Chamfer	For Drill Bit Size, mm	For Drill Bit Size Decimal Equiv.	ID	OD	Lg.	Drill Bushing Type	Material	Hardness		1-5	6-11	12-Up
55 mm ID



		70	67	One End	55	2.1654"	0.01 to 0.029	0.059 to 0.078	-0.01 to 0.254	PM	Steel	Rockwell C61	96990A987	0000000	000000	000000

Taper-Lock Bushings

Mount these hubless bushings flush into your sprocket or pulley for a slim profile with no protruding screws. They are for use with taper-lock sprockets of the same bushing trade number. As you tighten the included set screws, the bushing grips the shaft and pulls it into your sprocket or pulley.

			Keyway, mm
	For Shaft Dia., mm	Overall Wd., mm	Wd.	Dp.	Taper	Fastener Tightening Torque, in·lbf	Includes		Each
Steel







				Bushing Trade Number 3020

				55	51	16	4.3	8°	800	Set Screws	57095K363	000000