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Miniature Ball Bearings with Extended Inner Ring

Miniature ball bearings with extended inner ring, Extended inner ring miniature bearings, Precision miniature bearings, Small bearings for industrial applications, Miniature ball bearings with an extended inner ring are designed to provide additional axial support, making them ideal for applications where space is limited but stability is crucial.
Miniature ball bearings with extended inner ring are compact inch-size radial bearings designed with a wider inner ring than the outer ring, helping simplify shaft positioning, spacing and assembly in small mechanisms. This product list covers RW and SRW series options from 0.04688″ to 0.3125″ bore, with open and ZZ shielded versions in chrome steel or stainless steel. Buyers can compare bore, outer diameter, bearing width, inner ring width, external diameter on inner ring, radial load, speed and material directly in the list. These bearings are used in micro motors, instruments, dental tools, small pumps, printers, scanners, robotics and compact automation assemblies. TFL helps source standard replacements, EZO-style alternatives and custom options based on bearing number, drawing, sample or application requirements.
Total 68 Results
Part Number
Bore Dia
Outer Dia
Width
Ball Qty
System of Measurement
Dynamic Radial Load
Static Radial Load
Max Speed
Weight
Price（$）
SRW1-5zz
0.09375"
0.3125"
0.1406"
6
Inch
95 lbf
29 lbf
54000 rpm
1.15 g
3.834
RW1-5zz
0.09375"
0.3125"
0.1406"
6
Inch
106 lbf
32 lbf
60000 rpm
1.15 g
3.195
SRW133
0.09375"
0.1875"
0.0625"
10
Inch
25 lbf
9 lbf
72000 rpm
0.15 g
3.834
RW133
0.09375"
0.1875"
0.0625"
10
Inch
28 lbf
10 lbf
80000 rpm
0.15 g
3.195
SRW133zz
0.09375"
0.1875"
0.0937"
10
Inch
25 lbf
9 lbf
72000 rpm
0.15 g
3.834
RW133zz
0.09375"
0.1875"
0.0937"
10
Inch
28 lbf
10 lbf
80000 rpm
0.15 g
3.195
RW144
0.125"
0.25"
0.0937"
7
Inch
54 lbf
17 lbf
67000 rpm
0.40 g
2.655
SRW144
0.125"
0.25"
0.0937"
7
Inch
49 lbf
15 lbf
60300 rpm
0.40 g
3.186
SRW144zz
0.125"
0.25"
0.1094"
7
Inch
49 lbf
15 lbf
60300 rpm
0.40 g
3.186
RW144zz
0.125"
0.25"
0.1094"
7
Inch
54 lbf
17 lbf
67000 rpm
0.40 g
2.655
RW2
0.125"
0.375"
0.1562"
7
Inch
121 lbf
39 lbf
56000 rpm
1.37 g
2.655
SRW2
0.125"
0.375"
0.1562"
7
Inch
109 lbf
35 lbf
50400 rpm
1.37 g
3.186
RW2-5
0.125"
0.3125"
0.1094"
6
Inch
107 lbf
32 lbf
60000 rpm
0.74 g
2.655
SRW2-5
0.125"
0.3125"
0.1094"
6
Inch
96 lbf
29 lbf
54000 rpm
0.74 g
3.186
2 / 5
A Miniature Ball Bearings with Extended Inner Ring

The Extended Inner Ring Simplifies Installation

One notable feature of this type of bearing is that the width of its inner ring is greater than that of the outer ring. Generally, the inner ring is extended equally on both sides.
 
You can directly use the extended end face of the inner ring as a positioning surface to mate and fix with other components on the shaft, such as the shaft shoulder or lock nuts. This not only reduces the number of required parts and inventory types but also lowers the complexity and potential misalignment errors during assembly, making the installation of the bearing more straightforward, efficient, and cost-effective.
 
If you have such requirements, the miniature ball bearing with an extended inner ring will be your ideal choice.

Miniaturized Size for Narrow Spaces

As a member of the micro-bearings series, this type of bearing is renowned for its compact dimensions, with the inner diameter, outer diameter, and total width all controlled within the micrometre to millimetre range. This miniaturisation feature makes them indispensable key components in numerous precision small-scale devices.
 
These micro-bearings are widely used in products with strict space limitations, such as office automation equipment, computer hard disk drives, small pumps and valves, as well as various consumer electronics and models. In these application scenarios, the design of the extended inner ring not only maintains the compact size of the bearing but also provides a more convenient installation method, offering significant support for achieving the miniaturisation and high integration of the equipment.
A small pump, a game controller and a hard disk drive,

Better Shaft Support and Stability

The extended inner ring is designed not only to streamline the installation process but also to offer an expanded support span for the shaft. In certain specific applications, especially when the shaft is relatively thin or needs to bear a certain bending moment load, the standard width inner ring may not be sufficient to meet the required support stability.
 
The extended inner ring design increases the contact length between the bearing’s inner ring and the shaft, effectively transferring load and enhancing stiffness and rotational stability, especially under asymmetric loads or high-speed conditions. This offers a significant performance advantage for micro-rotating systems requiring high accuracy and reliability. By minimising vibration, it extends both the bearing’s service life and that of related components.

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Miniature Extended Inner Ring Bearing Selection Guide

Miniature ball bearings with extended inner ring are single-row radial bearings where the inner ring is wider than the outer ring. Use this list to compare bore, OD, width, inner ring width, inner-ring OD, open/ZZ type, material, radial load, and speed before sending an RFQ.

How to Choose This Bearing Type

Choose this category when the bearing must provide a built-in shaft spacer, an easier positioning surface, or wider inner-ring support in a compact assembly. If your design also needs an outer-ring flange for housing location, use miniature flanged ball bearings with extended inner ring instead. For standard miniature bearings without the extended inner ring, compare inch size miniature ball bearings.

Common Series and Model Range

Series / Option Typical Meaning Selection Notes
RW series Chrome steel miniature ball bearings with extended inner ring Common choice for clean, dry precision assemblies where cost and radial load capacity matter.
SRW series Stainless steel version of RW-style extended inner ring bearings Better for humid, lightly corrosive, or cleanliness-sensitive applications.
Open / ZZ Open or metal shielded versions Open type supports external lubrication; ZZ shields help retain grease and reduce light contamination.
Size coverage 0.04688″ to 0.3125″ bore, 0.15625″ to 0.625″ OD Confirm bore, OD, inner-ring width, inner-ring OD, and shaft layout before replacement.

How to Read a Model Number: Example SRW0ZZ

In SRW0ZZ, “S” indicates stainless steel, “RW” identifies the miniature extended inner ring bearing series, “0” is the size code, and “ZZ” means two metal shields. This model has a 0.04688″ bore, 0.15625″ OD, 0.0937″ width, and 0.1249″ inner ring width.

Open vs ZZ Selection

Open bearings are suitable when the assembly allows relubrication and low drag is important. ZZ shielded bearings are better when the bearing needs light dust protection and grease retention in small motors, instruments, printers, or compact mechanisms. This product list mainly covers open and ZZ shielded options; if a sealed 2RS version is required, confirm whether it can be sourced or customized.

Key Specifications to Confirm Before Quotation

For this bearing type, do not confirm only bore and OD. Also check the inner ring width, inner-ring OD, outer-ring width, shaft fit, adjacent gear or pulley position, radial clearance, material, speed, and load. These details determine whether the extended inner ring can replace a spacer or simplify the shaft assembly correctly.

EZO-Style Replacement Notes

RW and SRW model numbers are often searched as EZO-style replacement or cross-reference numbers. TFL can help customers source suitable alternatives after confirming the bearing number, drawing, sample, or application requirements. Brand names and part numbers should be used for identification and interchange checking only.

Common Applications

Common applications include dental tools, optical instruments, micro motors, compact pumps, valves, printers, scanners, office automation equipment, card readers, robotics joints, RC models, drones, and miniature gearboxes where a wider inner ring helps improve shaft positioning and assembly stability.

Popular Models / High-Demand Models

Model Example Typical Size / Feature Common Buying Scenario
SRW0ZZ 0.04688″ bore, stainless steel, ZZ shielded Good priority model for very small EZO-style SRW0ZZ replacement searches and urgent sourcing cases.
RW1ZZ / SRW1ZZ 0.05556″ bore, compact shielded RW/SRW option Useful for very small precision devices requiring a wider inner ring and light contamination protection.
RW2ZZ / SRW2ZZ 0.125″ bore, 0.375″ OD, shielded option Common small-size extended inner ring option for compact motors and instruments.
RW4ZZ 0.25″ bore, 0.625″ OD, higher radial load range Useful when the design still needs miniature dimensions but requires more radial load capacity.

Why Source from TFL

TFL helps customers source miniature extended inner ring bearings from qualified factory resources based on confirmed part numbers, drawings, samples, or application requirements. We check model, quantity, appearance, packaging, and basic quality requirements before shipment, then coordinate delivery. OEM packaging and custom requirements can be discussed for suitable orders.

Need Help Matching an RW or SRW Bearing?

Send your bearing number, drawing, sample photo, or application details. TFL can help confirm dimensions, inner ring width, material, shield type, and replacement options before quotation.

Request a Quote

TFL is a bearing supplier and sourcing partner. We provide replacement and alternative bearing options based on confirmed part numbers, drawings, or application requirements; we do not claim to be the original brand or an authorized distributor of third-party brands.

FREQUENTLY ASKED QUESTIONS

an image showing FAQ

Can the extended inner ring eliminate the need for shaft shoulders?

Not typically for location, but it acts like a built-in spacer against adjacent parts, simplifying the assembly stack-up on the shaft.

How do I find the exact width difference between the inner and outer rings?

This dimension is specific to each bearing size. Please consult the technical drawing or ball bearing size chart on the product page for precise data.

Are these Miniature Ball Bearings with Extended Inner Ring available with seals or shields?

Yes, many sizes are available in open, shielded (ZZ), or sealed (2RS) configurations to suit various operating environments. Check product options.

Do you offer samples? What is the Minimum Order Quantity (MOQ)?

Sample availability and Minimum Order Quantity (MOQ) can vary by product model. Please check the specific product page or contact our sales team for details on the bearing you need.
FAQ