Fit A Rear Derailleur

Introduction

The rear derailleur is a mechanism to control the chain tension. This is necessary as a derailleur system employs different amounts of chain when running in different gears. It's other function is to push the chain left or right so that it can shift between different gears.

Step 1

<h3>Step 1</h3><p>Most modern frames have an integrated gear hanger. This may be part of the actual frame, if the frame is made of steel. If the frame is made of aluminium it’s more likely to be bolted on so it can be replaced if it gets damaged. Some older – or low budget – frames have a hanger with a slot for the axle. This type clamps onto the slot where the back wheel fits, it has a small bolt and crescent-shaped nut that hold it in place when the wheel comes out and is held securely by the right side axle-nut of the rear wheel. In this case the hanger is either part of the rear derailer or a separate element.
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Gear Hanger

Most modern frames have an integrated gear hanger. This may be part of the actual frame, if the frame is made of steel. If the frame is made of aluminium it’s more likely to be bolted on so it can be replaced if it gets damaged. Some older – or low budget – frames have a hanger with a slot for the axle. This type clamps onto the slot where the back wheel fits, it has a small bolt and crescent-shaped nut that hold it in place when the wheel comes out and is held securely by the right side axle-nut of the rear wheel. In this case the hanger is either part of the rear derailer or a separate element.

Step 2

<h3>Step 2</h3><p>Grease the threads in the hole in the gear hanger.
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Grease

Grease the threads in the hole in the gear hanger.

Step 3

<h3>Step 3</h3><p>Introduce the fixing bolt of the rear derailleur into the hole in the hanger. The hanger has a tab on the back where the ‘C’ screw rests. Check the ‘C’ screw is in the right place to go past this tab without hitting it. Fully tighten the bolt to lock the derailleur to the bike.
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Screw On The Rear Derailleur

Introduce the fixing bolt of the rear derailleur into the hole in the hanger. The hanger has a tab on the back where the ‘C’ screw rests. Check the ‘C’ screw is in the right place to go past this tab without hitting it. Fully tighten the bolt to lock the derailleur to the bike.

Step 4

<h3>Step 4</h3><p>If the hanger is part of the frame or bolts directly on to the frame, screw the rear derailleur onto the bike. If the hanger has a slot and a crescent-shaped nut screw the rear derailleur into the hanger then clamp it into the right side wheel slot. Then fit the wheel to lock it in place.
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Attach A Slotted Hanger To The Frame

If the hanger is part of the frame or bolts directly on to the frame, screw the rear derailleur onto the bike. If the hanger has a slot and a crescent-shaped nut screw the rear derailleur into the hanger then clamp it into the right side wheel slot. Then fit the wheel to lock it in place.