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Round-Shaft Linear Bearings

Linear Guide Bearings

High Quality Linear Bearings

PBC Linear offers a comprehensive range of linear guide bearings, including round-shaft plain linear bearings, introduced with the self-lubricating Simplicity® bearing in 1983 to excel in harsh environments (like dirt, vibration, and washdowns), and round-shaft classic linear ball bearings for high-speed or cantilevered applications.

You can directly buy Round Shaft Linear Bearings online in our shop along with other types of bearing components for linear guides (such as CAM rollers, V-rollers and carriages with self-lubricating underliners).

The following discussion details key parameters for selecting linear guide bearings, including max static load, max speed, coefficient of friction, precision, environmental compatibility, and temperature range, with a focus on performance in contaminated, wet, dry, and clean room applications. It covers the 2:1 bearing ratio, addressing moment arm distance, bearing length, and cantilevered loads to prevent binding, alongside maximum PV (pressure velocity) for assessing dynamic capability through pressure and velocity calculations. The content also explores the PBC Linear bearing portfolio, including open and closed style pillow block bearings, die set and flange mount bearings, linear precision sleeve bearings, and square bearings, as well as Simplicity linear slides and shafting options like carbon steel, 400 series stainless steel, and ceramic-coated aluminum, available as bar stock, pre-drilled, or cut-to-length with tailored machined ends, all optimized for diverse linear motion applications.

Plain Linear Bearings Vs Linear Ball Bearings

Both plain bearings and ball bearings have advantages and disadvantages. Use the chart below to help guide your decision-making process. If you require more assistance, be sure to contact your local representative for more guidance on the linear motion bearing selection process.

Bearing Type Max Static Load (Horizontal) Max Speed Coefficient of Friction Precision Environment Temperature
Plain Bearing 100,500 lbs (447,046 N) 300 SFM (1.52 m/sec)
With Lubrication: 825 SFM (4.19 m/sec)		 0.125 Consistent over life and in a variety of environments
Running clearance = 0.0005" (0.0127 mm) per side		 Excels in contaminated, wet, dry, and clean room applications
View our full Chemical Reaction Chart		 -400°F / +400°F
Ball Bearing 2,165 lbs (9,630 N) 590 SFM (3 m/s)
Always requires lubrication		 Average = 0.05 Can change dramatically dependent on environmental conditions
Can be preloaded, virtually eliminating play		 Best suited for general manufacturing applications -4°F / +176°F

Design Considerations for Plain Bearings

2:1 Bearing Ratio for Plain Linear Bearings

The 2:1 Bearing Ratio is officially defined as the maximum ratio of moment arm distance to bearing length which will not cause binding or prevent motion. The Binding Ratio is often displayed numerically as “2:1,” where “2” is the moment arm distance and “1” is bearing length. For example, if 2x equals 10 inches then 1x must equal 5 inches. This rule applies to all plain bearings with cantilevered loads.

2:1 Linear Bearing Ration

Plain Linear Bearings’ Maximum PV

The maximum pressure velocity (max PV) value should also be considered when designing applications with plain bearings. Plain bearings are graded according to their maximum PV value, determined by the load per unit area and velocity. Another word for a bearings’ max PV is its maximum dynamic capability.

To be deemed fit for application without lubrication, plain bearings must satisfy three specific criteria:

Calculate Pressure 


  • P = Maximum pressure or load in pounds per square inch (psi) or kilograms per square centimeter (kg/cm2) 
  • A = Projected Contact Area 
  • L = Bearing Length 
  • d = Shaft diameter 
  • W = Maximum load 

Calculate Velocity 


  • V = Maximum velocity or surface speed in square feet per minute (sfm) or meters per minute (m/min) 
  • N = Rotational velocity

Calculate Maximum PV 


PV = The performance measurement of plain bearings

Linear Motion Bearing Technology Provides Endless Possibilities

The superior technology behind PBC Linear plain bearings and ball bearings is applied to all products in our bearing portfolio. If a round bearing is not what you need, PBC Linear has other bearing styles that may be better suited for your application.

The superior technology behind PBC Linear plain bearings and ball bearings is applied to all products in our bearing portfolio. If a round bearing is not what you need, PBC Linear has other bearing styles that may be better suited for your application.

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Open & Closed Style Pillow Block Linear Bearings

Pillow Blocks

Can be bolted to a secure foundation that is parallel to the axis of rotation and used in low-torque, light load applications.  

Die Set Flange Mounted Bearing

Die Set Flange Mount Linear Bearings

Mounting precision with sizes that are interchangeable with industry standard die sets

Flange Mount Linear Bearings

Flange Mount Linear Bearings

Provide ease of mounting and supports heavy loads where the shaft axis is perpendicular to the mounting surface.

Linear Precision Sleeve Bearings

Linear Sleeve Bearings

Replaces Oilite, bronze, and plastic bearings and is ideal for slow or moderate speeds for oscillating or rotary motion.

Square Linear Bearings

Square Bearings

Resists torque and eliminate extra costly components in parallel shafts.

Leverage High Quality Bearing Assemblies

Our use of Simplicity plain bearing and ball bearing technology doesn’t just stop with bearings. PBC Linear utilizes bearings in our Simplicity Linear Slides.

Learn more about our fully modular Linear Slide system

Simplicity Linear Slide Actuator Assembly
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The Perfect Pair: PBC Linear Shafts & Bearings

PBC Linear shafting is meticulously designed to perfectly complement high-performance linear motion bearing technology, ensuring prolonged lifespan, minimal maintenance, and dependable linear motion. Regardless of whether you’re using plain bearings or ball bearings, PBC Linear offers the best shafts suited for the job. Available in three standard materials—Carbon Steel, 400 Series Stainless Steel, and Ceramic Coated Aluminum—these shafts cater to a diverse array of applications. Shafting options are offered as either bar stock or pre-drilled, available in standard lengths or customizable cut-to-length configurations, with the option for tailored machined ends.

To learn more about our Linear Shaft offerings, be sure to check out our Engineered for Maximum Linear Bearing Performance blog post.