Derailleur jockey and pulley wheel dimensions

A customer wanted some replacement derailleur wheels, which necessitated our measuring the pulleys of various makers' derailleurs. We thought we'd share that info here.

Maker: '94-'08 Campagnolo | Simplex | SunTour | Tacx Blue 10-tooth | Tacx Black 11-tooth

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1994 - 2008 Campagnolo pulley wheels

• Outside diameter: 38.58mm
• Internal diameter of the pulley's hole: 8mm
• Internal diameter of the pulley bushing that the securing bolt goes through: 5mm
• Pulley has 10 teeth

The pulley pictured below is from a 10-speed aluminum Chorus rear derailleur, which was made in 2002 & 2003.

This pulley is compatible with the following derailleurs:

• ’94-’96 Pulley wheels were RD-RE004, 9s.
• ’97 Pulley wheels were RD-RE104, 9s.
• ’98 Pulley wheels were RD-RE600 9s.
• ’99 Pulley wheels were RD-RE700, 9s.
• 2001-03 Pulley wheels were RD-RE600 for 9s Record and Chorus.
• 2001-03 Pulley wheels were RD-RE700 for 10s.
• 2004-2008 RD-RE600 10s with a width of 8.8mm for Record, and 8.4mm for Chorus and below.

Campagnolo began producing 11-speed systems in 2009.

Outside diameter of the pulley, 38.6mm

Internal diameter of the pulley bushing the bolt goes through.

Inside diameter of the pulley is 8mm

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Simplex pulley wheels:

• Outside diameter: 36.25mm
• Internal diameter of the pulley bushing (far left in 1st picture) that the securing bolt goes through: 6mm
• Pulley has 10 teeth

A Simplex pulley, disassembled.

The outside diameter, 36.25mm

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SunTour pulley wheels

• Outside diameter of pulley: 38mm
• External diameter of the bushing is 10mm.
• Internal diameter of the bushing is just about 6mm
• Pulley has 10 teeth

A new, bare pulley wheel.

Let's call it 38mm.

External diameter of the bushing is 10mm.

Internal diameter is just about 6mm

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Tacx blue pulley wheels

Compatible with these derailleurs:

• Shimano 7 & 8-speed
• Campagnolo 8, 9 & 10-speed
• SRAM-ESP before 2000

Dimensions:

• Outside diameter of pulley: 38.13mm
• Internal diameter of the pulley bushing that the securing bolt goes through: 7mm
• Pulley has 10 teeth

The micrometer says the internal diameter of the pulley bushing is 6.99mm. Let's call it 7mm.

Tacx pulleys come with different sets of adapters for different derailleurs. This set has an internal diameter of 6mm.

Here's the outside diameter, 38.13mm.

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Tacx black 11-tooth pulley wheels

Dimensions:

• Outside diameter of pulley: 41.42mm
• Internal diameter of the pulley bushing that the securing bolt goes through: 6.93mm
• Pulley has 11 teeth

Here's the box they come in.

Internal diameter of the pulley bushing is 6.93mm.

Tacx pulleys come with different sets of adapters for different derailleurs. This set has an internal diameter of 6mm.

Outside diameter is 41.42mm

Here are the pulley wheels and the bushings.

And which ones go with what derailleurs

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