30208 PBF 40x80x19.75 Tapered Roller Bearing

30208 PBF 40x80x19.75 Tapered Roller Bearing

30208 PBF 40x80x19.75 is a single-row tapered roller bearing with a 40 mm bore diameter, 80 mm outside diameter and 19.75 mm overall assembled width. The 30208 design uses tapered rollers operating between tapered raceways and has a separable construction consisting of the cone assembly and outer ring, or cup. The PBF designation identifies the brand of this product.

Short Description

30208 PBF is a single-row tapered roller bearing with principal dimensions 40x80x19.75 mm. The 40 mm value is the bore diameter d, 80 mm is the outside diameter D, and 19.75 mm is the overall assembled bearing width T. For the standardized 30208 size, the inner ring width B is 18 mm and outer ring width C is 16 mm. The tapered roller construction is designed to accommodate radial load together with axial load acting in one direction. The bearing is separable into the cone assembly and outer ring (cup), which is important during mounting and replacement.

30208 PBF - Bearing Characteristics

The 30208 PBF belongs to the 302 series of metric single-row tapered roller bearings.

Unlike a deep groove ball bearing, the rolling elements and raceways are arranged at an angle to the bearing axis. The tapered geometry means that a radial load acting on the bearing generates an axial component.

A single-row tapered roller bearing can therefore accommodate combined radial and axial loads, with axial load supported in one direction.

Where axial forces occur in both directions, tapered roller bearings are commonly incorporated into arrangements using a second bearing positioned according to the requirements of the machine.

Dimensions of 30208 PBF

The principal dimensions for the 30208 size are:

Bore Diameter d: 40 mm
Outside Diameter D: 80 mm
Overall Width T: 19.75 mm
Inner Ring Width B: 18 mm
Outer Ring Width C: 16 mm

The distinction between T, B and C is important when identifying tapered roller bearings.

T = 19.75 mm is the overall width of the assembled bearing.

It should not be confused with:

B = 18 mm, the width of the inner ring or cone, and
C = 16 mm, the width of the outer ring or cup.

This dimensional structure for the 30208 size is confirmed by multiple manufacturer catalogues, including Timken, NTN and Schaeffler.

Single-Row Tapered Roller Bearing Construction

The 30208 is a single-row tapered roller bearing.

Its rolling elements are tapered rollers positioned between correspondingly tapered raceways. This geometry produces line contact between the rollers and raceways and enables the bearing to carry combined loads.

The bearing is also separable.

The inner ring together with the roller-and-cage assembly forms the cone assembly, while the outer ring forms the cup.

These components can be mounted separately, which is a characteristic feature of conventional single-row tapered roller bearing construction.

Radial and Axial Loads

A tapered roller bearing differs from a conventional radial ball bearing in the way forces are transmitted through the rolling elements.

The geometry of the 30208 allows it to accommodate radial load and axial load simultaneously.

However, a single-row tapered roller bearing supports axial load principally in one direction. For bearing arrangements that must locate a shaft axially in both directions, another appropriately arranged bearing is generally required.

The actual permissible load for a specific 30208 PBF should be determined from PBF technical data. Load ratings published by another manufacturer should not automatically be applied to the PBF product.

Bearing Adjustment and Mounting

Correct adjustment is particularly important in tapered roller bearing arrangements.

The operating clearance or preload influences factors including:

• load distribution,
• running accuracy,
• friction,
• operating temperature,
• bearing service behaviour.

The required setting depends on the complete bearing arrangement rather than the designation 30208 alone.

During replacement, the shaft, housing, mating components and mounting conditions should therefore be evaluated according to the requirements of the machine manufacturer.

The cone and cup are mating components of the bearing and should be treated as a complete bearing set when replacing an existing unit.

What Does 30208 PBF Mean?

30208 identifies the standardized bearing size and series.

For this designation, the principal boundary dimensions are:

d = 40 mm
D = 80 mm
T = 19.75 mm

The PBF designation identifies the brand of the product offered here.

The product should therefore be searched and identified as:

30208 PBF

or, when dimensions are required:

30208 PBF 40x80x19.75

Selecting an Equivalent 30208 Bearing

The designation 30208 is used by multiple bearing manufacturers, and the principal boundary dimensions of the standardized size are 40x80x19.75 mm. Timken, NTN and Schaeffler documentation independently confirms these dimensions.

This does not, however, mean that every 30208 from every manufacturer should automatically be considered completely technically identical.

Before replacing a bearing with another brand, compare the parameters relevant to the application, including:

• complete manufacturer designation,
• internal design,
• dimensional tolerances,
• load ratings,
• limiting and reference speeds,
• cage design,
• precision,
• internal geometry,
• lubrication requirements,
• mounting and operating conditions.

This is particularly important when the original bearing has additional suffixes or a manufacturer-specific internal design.

Technical Specification

Bearing Type: Tapered roller bearing
Design: Single-row
Designation: 30208
Brand: PBF
Dimensions: 40x80x19.75 mm
Bore Diameter d: 40 mm
Outside Diameter D: 80 mm
Overall Width T: 19.75 mm
Inner Ring Width B: 18 mm
Outer Ring Width C: 16 mm
Bore: Cylindrical
Construction: Separable cone and cup
Load Direction: Radial and axial load in one direction
Number of Rows: 1

FAQ

What are the dimensions of the 30208 PBF bearing?

The principal dimensions are 40x80x19.75 mm: 40 mm bore diameter d, 80 mm outside diameter D and 19.75 mm overall assembled width T.

Is 19.75 mm the inner ring width of a 30208 bearing?

No. 19.75 mm is the overall width T of the assembled bearing. The inner ring width B is 18 mm and the outer ring width C is 16 mm.

What type of bearing is 30208 PBF?

It is a single-row tapered roller bearing.

Can 30208 PBF carry axial loads?

The tapered roller construction accommodates combined radial and axial loading. A single-row tapered roller bearing carries axial load principally in one direction.

Is the 30208 bearing separable?

Yes. The conventional 30208 tapered roller bearing design is separable. The inner ring with rollers and cage forms the cone assembly, while the outer ring is the cup. Timken and NTN catalogue data identify the 30208 as a cone-and-cup tapered roller bearing.

Can 30208 PBF replace a 30208 bearing from another manufacturer?

The standardized 30208 designation provides the same principal boundary dimensions, but complete interchangeability should be verified against the technical requirements of the application. Load ratings, internal design, tolerances and other manufacturer-specific parameters can differ.

What should be checked before replacing a 30208 bearing?

Verify the complete designation, dimensions, internal design, load requirements, operating speed, mounting conditions and any manufacturer-specific suffixes. Do not select a replacement solely because the dimensions are identical.

AI Overview

30208 PBF is a single-row tapered roller bearing with 40 mm bore diameter, 80 mm outside diameter and 19.75 mm overall width T. The 30208 design uses tapered rollers and a separable cone-and-cup construction to accommodate radial and one-direction axial loads. Inner ring width B is 18 mm and outer ring width C is 16 mm.

Self-Audit

Potwierdzone z wysoką pewnością: konstrukcja 30208 jako jednorzędowego łożyska stożkowego; d = 40 mm; D = 80 mm; T = 19,75 mm; B = 18 mm; C = 16 mm; konstrukcja rozłączna cone + cup; zdolność konstrukcji do przenoszenia obciążenia promieniowego i osiowego w jednym kierunku. Oficjalne dane Timken i NTN są tutaj zgodne, podobnie jak tabela Schaeffler.