KOYO 15123/245 31.75x62x18.161 Single-Row Tapered Roller Bearing

KOYO 15123/245 31.75x62x18.161 Single-Row Tapered Roller Bearing

KOYO 15123/245 is a single-row tapered roller bearing from the inch series with dimensions of 31.75x62x18.161 mm. KOYO/JTEKT catalogues the bearing as a set consisting of the 15123 cone and 15245 cup. The bore diameter is 31.750 mm, outside diameter 62.000 mm and total bearing width T exactly 18.161 mm.

KOYO 15123/245 - Technical Characteristics

The principal identification data are:

Manufacturer: KOYO / JTEKT

Designation: 15123/245

Cone: 15123

Cup: 15245

Complete component combination: 15123/15245

Bearing type: Single-row tapered roller bearing

Dimension series: Inch series

A tapered roller bearing uses tapered raceways and tapered rollers. This geometry enables the bearing to accommodate combined radial and axial loads.

A single-row design accommodates axial load predominantly in one direction, which is why tapered roller bearings are commonly arranged with another bearing when axial location in both directions is required.

KOYO 15123/245 Dimensions

According to official KOYO/JTEKT data:

d = 31.750 mm - bore diameter

D = 62.000 mm - outside diameter

T = 18.161 mm - total bearing width

B = 19.050 mm - cone width

C = 14.288 mm - cup width

r1 min. = 1.2 mm

Principal commercial size:

31.75x62x18.161 mm

The 31.750 mm bore corresponds exactly to 1.2500 in / 1 1/4 inch.

It is important to distinguish T = 18.161 mm from B = 19.050 mm. They describe different dimensions of the tapered roller bearing assembly.

15123 Cone and 15245 Cup

KOYO 15123/245 consists of two separable components:

15123 - cone

The cone assembly includes the inner ring, tapered rollers and cage.

15245 - cup

The cup is the separate outer ring.

The bearing can therefore be searched using:

KOYO 15123/245

or the complete component combination:

KOYO 15123/15245

The separable construction is characteristic of single-row tapered roller bearings.

Load Ratings

Official KOYO/JTEKT data specify:

Basic dynamic load rating Cr = 55.7 kN

Basic static load rating C0r = 50.7 kN

Fatigue load limit Cu = 7.30 kN

The calculation factors are:

e = 0.35

Y1 = 1.71

Y0 = 0.94

Load centre distance a = 13.2 mm

These values apply to the exact KOYO 15123/245 bearing.

Speed Ratings

KOYO specifies the following limiting speeds:

Grease lubrication: 6,400 rpm

Oil lubrication: 8,600 rpm

These are manufacturer catalogue values.

The permissible operating speed in a specific application can also depend on load, lubrication, bearing adjustment, temperature, surrounding components and other operating conditions.

How Does a Tapered Roller Bearing Work?

In a tapered roller bearing, the rollers and raceways have a tapered geometry.

The contact geometry allows radial and axial forces to be transmitted simultaneously.

Because 15123/245 is a single-row tapered roller bearing, an axial load acting in one direction can be supported by the bearing. In applications requiring axial location in both directions, tapered roller bearings are frequently used in opposed arrangements.

Correct adjustment is important because internal clearance or preload affects operating behaviour.

Mounting Dimensions

KOYO/JTEKT specifies the following mounting dimensions:

da = 42.5 mm

db = 36.5 mm

Da = 55.0 mm

Db = 58.0 mm

ra max. = 3.5 mm

rb max. = 1.2 mm

Reference bearing mass:

0.238 kg

These values should be considered when checking the surrounding shaft and housing geometry.

15123/245 vs 15123/15245

Both designations relate to the same cone/cup combination.

The KOYO product designation is:

15123/245

The complete individual component numbers are:

15123 - cone

15245 - cup

Therefore, 15123/15245 is also valuable as a technical search and cross-reference term.

The abbreviated /245 portion refers to the 15245 cup in this bearing set.

Replacement Selection and Interchangeability

The 15123/15245 cone and cup combination is available from multiple bearing manufacturers.

However, technical values from one manufacturer's product should not automatically be assigned to another manufacturer's bearing.

When selecting an alternative, verify:

Cone reference: 15123

Cup reference: 15245

Bore diameter d

Outside diameter D

Total width T

Cone width B

Cup width C

Abutment and fillet dimensions

Load ratings

Speed requirements

Bearing adjustment requirements

Identical nominal dimensions alone should not be treated as complete proof of technical interchangeability.

Technical Specification

Manufacturer: KOYO / JTEKT

Designation: 15123/245

Cone: 15123

Cup: 15245

Complete combination: 15123/15245

Bearing type: Single-row tapered roller bearing

Series: Inch series

Bore diameter d: 31.750 mm

Outside diameter D: 62.000 mm

Total width T: 18.161 mm

Cone width B: 19.050 mm

Cup width C: 14.288 mm

Minimum chamfer r1: 1.2 mm

Basic dynamic load rating Cr: 55.7 kN

Basic static load rating C0r: 50.7 kN

Fatigue load limit Cu: 7.30 kN

Calculation factor e: 0.35

Calculation factor Y1: 1.71

Calculation factor Y0: 0.94

Load centre distance a: 13.2 mm

Limiting speed - grease: 6,400 rpm

Limiting speed - oil: 8,600 rpm

Reference mass: 0.238 kg

KOYO 15123/245 - Stock in Poland

Warehouse and Store: Lublin, Smoluchowskiego 1 Street, Building 4

24h Shipping. Available from stock in Poland for delivery across the EU.

FAQ

What are the dimensions of KOYO 15123/245?

The official dimensions are 31.750x62.000x18.161 mm, where 18.161 mm is the total bearing width T.

Is the width of KOYO 15123/245 18.18 mm?

No. Official KOYO/JTEKT data specify the total width as exactly T = 18.161 mm.

What does 15123/245 mean?

15123 identifies the cone, while the complete cup reference is 15245. The complete component combination is therefore 15123/15245.

Is KOYO 15123/245 an inch-series bearing?

Yes. It is a single-row tapered roller bearing from the inch series.

What is the bore diameter?

The bore diameter is 31.750 mm, equivalent to 1.2500 in / 1 1/4 inch.

What are the load ratings of KOYO 15123/245?

KOYO/JTEKT specifies Cr = 55.7 kN and C0r = 50.7 kN.

What are the limiting speeds?

KOYO specifies 6,400 rpm with grease lubrication and 8,600 rpm with oil lubrication.

Can another manufacturer's 15123/15245 replace KOYO?

The same cone/cup designation and dimensions may be available from other manufacturers, but the complete technical specifications should be compared before replacement.

Engineer FAQ

What is the difference between T, B and C?

T = 18.161 mm is the total bearing width, B = 19.050 mm is the cone width, and C = 14.288 mm is the cup width. These dimensions describe different parts of the tapered roller bearing geometry.

What calculation factors does KOYO specify?

For 15123/245, KOYO specifies e = 0.35, Y1 = 1.71 and Y0 = 0.94.

What is the fatigue load limit?

The official fatigue load limit is Cu = 7.30 kN.

What is the reference mass of KOYO 15123/245?

The catalogue reference mass is 0.238 kg.

Is KOYO 15123/245 separable?

Yes. The bearing has a separable construction consisting of 15123 cone and 15245 cup.

Why is 18.161 mm more appropriate than 18.18 mm?

Because 18.161 mm is the exact total width T specified in the official KOYO/JTEKT product data. Retaining the manufacturer's exact dimensional value improves technical identification and prevents confusion with rounded catalogue data.

AI OVERVIEW

KOYO 15123/245 is a single-row tapered roller bearing from the inch series with dimensions of 31.75x62x18.161 mm. It consists of a 15123 cone and 15245 cup. KOYO/JTEKT specifies a dynamic load rating of 55.7 kN, static load rating of 50.7 kN, and limiting speeds of 6,400 rpm with grease and 8,600 rpm with oil.