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Idler Sprockets – Chain Tensioning and Alignment Solutions

Bolton Engineering Products Ltd supplies a complete range of idler sprockets designed to enhance chain performance, minimize wear, and keep proper tension in roller chain systems. 

Our idler sprockets with bearings are developed to ANSI standards and provide a precise fit and long-term reliability for a variety of industrial, agricultural, and mechanical uses. Whether you require a fixed idler sprocket or a chain idler sprocket on a tensioning arm, BEP Ltd has a solution in stock.

What Is an Idler Sprocket?

An idler sprocket (also known as an idler wheel) is a hubless sprocket fitted with a sealed ball bearing, allowing it to rotate freely around a fixed shaft or tension arm.
Its main function is to guide, tension, and maintain alignment in roller chain systems — particularly when chain length, routing, or load variation causes slack.

Common Uses Include:

  • Reducing chain vibration and noise
  • Maintaining correct chain engagement with drive and driven sprockets
  • Routing chains around obstructions or corners
  • Compensating for chain stretch over time

Technical Specifications

Specification

Details

Product Type

Chain Idler Sprocket

Design

Flat, Hubless with Pressed Bearing

Bearing Type

Sealed Ball Bearing with Wide Inner Race

Material

Hardened Steel / Carbon Steel

Tooth Hardness

Induction-Hardened Teeth for Extended Life

Chain Pitch Compatibility

ANSI Standard Roller Chain Sizes (25 – 100 & Above)

Mounting Type

Fixed Shaft / Tensioned Arm

Lubrication

Maintenance-Free Sealed Bearing

Optional Features

Double-Row Bearings / Stainless Steel Models Available

Compliance

ANSI / ISO Standards

 

Key Features & Benefits

  • Sealed Bearings: High-Quality Sealed Ball Bearings are used for every sprocket. 
  • Hardened Teeth: Heat actively and precisely machined for extended component life. 
  • Flexible Installation: Compatible with Fixed shaft or Tensioned Arm installation.
  • Standard Compatibility: Suitable for every ANSI standard roller chain pitch, so it can be easily replaced
  • Improved Chain Life: Enhances chain life by reducing chain vibration, wear, and elongation

Why Choose Bolton Engineering Products Ltd?

As a leading UK supplier and idler sprocket stockist, BEP Ltd offers:

  • Large UK stock of idler sprockets with bearings in multiple chain pitches
  • Same-day dispatch on in-stock items
  • Expert technical support for sizing and compatibility
  • Competitive pricing and dependable aftersales service
  • Options for engineer class idler sprockets and stainless-steel variants

Trust Bolton Engineering Products Ltd to deliver precision, reliability, and long-lasting performance in every idler sprocket you buy.

FAQs

Q1: What is an idler sprocket used for?

An idler sprocket is used to maintain chain tension, alignment, and engagement in a roller chain system. It helps prevent slack, vibration, and uneven wear.

Q2: What’s the distinction between a chain idler sprocket and a drive sprocket?

These sprockets don’t run torque like drive sprockets; the equipment rotates free-flowing on and on a bearing.

Q3: Do idler sprockets come with bearings?

Yes. BEP Ltd’s idler sprockets with bearings feature high-quality, sealed ball bearings that require no maintenance.

Q4: Can I use an idler sprocket for high-speed applications?

Yes, as long as the bearing and chain pitch are rated for the required speed and load. We supply heavy-duty and high-speed compatible models.

Roller Chain Idler Sprockets

Idler Sprockets – Chain Tensioning and Alignment Solutions

Bolton Engineering Products Ltd supplies a complete range of idler sprockets designed to enhance chain performance, minimize wear, and keep proper tension in roller chain systems. 

Our idler sprockets with bearings are developed to ANSI standards and provide a precise fit and long-term reliability for a variety of industrial, agricultural, and mechanical uses. Whether you require a fixed idler sprocket or a chain idler sprocket on a tensioning arm, BEP Ltd has a solution in stock.

What Is an Idler Sprocket?

An idler sprocket (also known as an idler wheel) is a hubless sprocket fitted with a sealed ball bearing, allowing it to rotate freely around a fixed shaft or tension arm.
Its main function is to guide, tension, and maintain alignment in roller chain systems — particularly when chain length, routing, or load variation causes slack.

Common Uses Include:

  • Reducing chain vibration and noise
  • Maintaining correct chain engagement with drive and driven sprockets
  • Routing chains around obstructions or corners
  • Compensating for chain stretch over time

Technical Specifications

Specification

Details

Product Type

Chain Idler Sprocket

Design

Flat, Hubless with Pressed Bearing

Bearing Type

Sealed Ball Bearing with Wide Inner Race

Material

Hardened Steel / Carbon Steel

Tooth Hardness

Induction-Hardened Teeth for Extended Life

Chain Pitch Compatibility

ANSI Standard Roller Chain Sizes (25 – 100 & Above)

Mounting Type

Fixed Shaft / Tensioned Arm

Lubrication

Maintenance-Free Sealed Bearing

Optional Features

Double-Row Bearings / Stainless Steel Models Available

Compliance

ANSI / ISO Standards

 

Key Features & Benefits

  • Sealed Bearings: High-Quality Sealed Ball Bearings are used for every sprocket. 
  • Hardened Teeth: Heat actively and precisely machined for extended component life. 
  • Flexible Installation: Compatible with Fixed shaft or Tensioned Arm installation.
  • Standard Compatibility: Suitable for every ANSI standard roller chain pitch, so it can be easily replaced
  • Improved Chain Life: Enhances chain life by reducing chain vibration, wear, and elongation

Why Choose Bolton Engineering Products Ltd?

As a leading UK supplier and idler sprocket stockist, BEP Ltd offers:

  • Large UK stock of idler sprockets with bearings in multiple chain pitches
  • Same-day dispatch on in-stock items
  • Expert technical support for sizing and compatibility
  • Competitive pricing and dependable aftersales service
  • Options for engineer class idler sprockets and stainless-steel variants

Trust Bolton Engineering Products Ltd to deliver precision, reliability, and long-lasting performance in every idler sprocket you buy.

FAQs

Q1: What is an idler sprocket used for?

An idler sprocket is used to maintain chain tension, alignment, and engagement in a roller chain system. It helps prevent slack, vibration, and uneven wear.

Q2: What’s the distinction between a chain idler sprocket and a drive sprocket?

These sprockets don’t run torque like drive sprockets; the equipment rotates free-flowing on and on a bearing.

Q3: Do idler sprockets come with bearings?

Yes. BEP Ltd’s idler sprockets with bearings feature high-quality, sealed ball bearings that require no maintenance.

Q4: Can I use an idler sprocket for high-speed applications?

Yes, as long as the bearing and chain pitch are rated for the required speed and load. We supply heavy-duty and high-speed compatible models.

4SR16 1/2" 16 Tooth 08Bx16 - Roller Chain Idler Sprocket

Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

4SR16 08Bx16 Roller Chain Idler Sprocket Chain Size 08B Teeth 16 Outside Diameter de (mm) 69.5 Pitch Diameter dp (mm) 65.1 Tooth Widt...

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Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

3SR21 3/8" 21 Tooth 06Bx21 - Roller Chain Idler Sprocket

Original price $6.00 - Original price $6.00
Original price
$6.00
$6.00 - $6.00
Current price $6.00

3SR21 06Bx21 Roller Chain Idler Sprocket Chain Size 06B Teeth 21 Outside Diameter de (mm) 68 Pitch Diameter dp (mm) 63.91 Tooth Width...

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Original price $6.00 - Original price $6.00
Original price
$6.00
$6.00 - $6.00
Current price $6.00

5SR14 5/8" 14 Tooth 10Bx14 - Roller Chain Idler Sprocket

Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

5SR14 10Bx14 Roller Chain Idler Sprocket Chain Size 10B Teeth 14 Outside Diameter de (mm) 78 Pitch Diameter dp (mm) 71.34 Tooth Width...

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Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

4SR18 1/2" 18 Tooth 08Bx18 - Roller Chain Idler Sprocket

Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

4SR18 08Bx18 Roller Chain Idler Sprocket Chain Size 08B Teeth 18 Outside Diameter de (mm) 77.8 Pitch Diameter dp (mm) 73.14 Tooth Wid...

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Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

8mm 23 Tooth 05Bx23 - Roller Chain Idler Sprocket

Original price $6.00 - Original price $6.00
Original price
$6.00
$6.00 - $6.00
Current price $6.00

8mm 23 Tooth 05Bx23 Roller Chain Idler Sprocket Chain Size 05B Teeth 23 Outside Diameter de (mm) 62 Pitch Diameter dp (mm) 58.75 Toot...

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Original price $6.00 - Original price $6.00
Original price
$6.00
$6.00 - $6.00
Current price $6.00

6SR13 3/4" 13 Tooth 12Bx13 - Roller Chain Idler Sprocket

Original price $9.00 - Original price $9.00
Original price
$9.00
$9.00 - $9.00
Current price $9.00

6SR13 12Bx13 Roller Chain Idler Sprocket Chain Size 12B Teeth 13 Outside Diameter de (mm) 87.5 Pitch Diameter dp (mm) 79.59 Tooth Wid...

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Original price $9.00 - Original price $9.00
Original price
$9.00
$9.00 - $9.00
Current price $9.00

8SR12 1" 12 Tooth 16Bx12 - Roller Chain Idler Sprocket

Original price $11.00 - Original price $11.00
Original price
$11.00
$11.00 - $11.00
Current price $11.00

8SR12 16Bx12 Roller Chain Idler Sprocket Chain Size 16B Teeth 12 Outside Diameter de (mm) 109 Pitch Diameter dp (mm) 98.14 Tooth Widt...

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Original price $11.00 - Original price $11.00
Original price
$11.00
$11.00 - $11.00
Current price $11.00

5SR17 5/8" 17 Tooth 10Bx17 - Roller Chain Idler Sprocket

Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

5SR17 10Bx17 Roller Chain Idler Sprocket Chain Size 10B Teeth 17 Outside Diameter de (mm) 93 Pitch Diameter dp (mm) 86.30 Tooth Width...

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Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

5SR15 5/8" 15 Tooth 10Bx15 - Roller Chain Idler Sprocket

Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

5SR15 10Bx15 Roller Chain Idler Sprocket Chain Size 10B Teeth 15 Outside Diameter de (mm) 83 Pitch Diameter dp (mm) 76.36 Tooth Width...

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Original price $8.00 - Original price $8.00
Original price
$8.00
$8.00 - $8.00
Current price $8.00

6SR15 3/4" 15 Tooth 12Bx15 - Roller Chain Idler Sprocket

Original price $9.00 - Original price $9.00
Original price
$9.00
$9.00 - $9.00
Current price $9.00

6SR15 12Bx15 Roller Chain Idler Sprocket Chain Size 12B Teeth 15 Outside Diameter de (mm) 99.8 Pitch Diameter dp (mm) 91.63 Tooth Wid...

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Original price $9.00 - Original price $9.00
Original price
$9.00
$9.00 - $9.00
Current price $9.00

081 18 Tooth 081x18 - Roller Chain Idler Sprocket

Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

081 18 Tooth 081x18 Roller Chain Idler Sprocket Chain Size 081 Teeth 18 Outside Diameter de (mm) 78.9 Pitch Diameter dp (mm) 73.14 To...

View full details
Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

10SR13 1.1/4" 13 Tooth 20Bx13 - Roller Chain Idler Sprocket

Original price $20.00 - Original price $20.00
Original price
$20.00
$20.00 - $20.00
Current price $20.00

10SR13 20Bx13 Roller Chain Idler Sprocket Chain Size 20B Teeth 13 Outside Diameter de (mm) 147.8 Pitch Diameter dp (mm) 132.65 Tooth ...

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Original price $20.00 - Original price $20.00
Original price
$20.00
$20.00 - $20.00
Current price $20.00

083 18 Tooth 083x18 - Roller Chain Idler Sprocket

Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

083 18 Tooth 083x18 Roller Chain Idler Sprocket Chain Size 083 Teeth 18 Outside Diameter de (mm) 78.9 Pitch Diameter dp (mm) 73.14 To...

View full details
Original price $7.00 - Original price $7.00
Original price
$7.00
$7.00 - $7.00
Current price $7.00

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