Replacing Cog and Lockring on the Rear Wheel of a Retrospec Fixed-Gear Bicycle

Introduction

Fixed gear bikes are a great way to get around but only offer one set speed. If you want to change that speed you don’t need to buy a whole new bike. By replacing the cog on the rear wheel with a different size you can adjust the speed.

For this replacement, you will be removing the back wheel from the rim and chain. This can lead to grease getting on hands as well as clothes. You may want to wear gloves and clothes that you are not afraid to get dirty. The cog will also have some grease on it as well.

When removing the cog with the chain whip make sure that the tool is properly placed on the cog. It takes a good amount of force to loosen the cog initially. If the tool slips there is a chance your hand could be cut on the cog or hit the ground.

What you need

Step 1 Cog and lockring

Replacing Cog and Lockring on the Rear Wheel of a Retrospec Fixed-Gear Bicycle, Cog and lockring: step 1, image 1 of 1

Remove the 9.5mm bolts on the rear wheel with an adjustable wrench. There is a bolt on each side of the wheel.

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Step 2

Replacing Cog and Lockring on the Rear Wheel of a Retrospec Fixed-Gear Bicycle: step 2, image 3 of 3

Loosen the 4mm by 50.8mm chain tension screw with a hex key. There is a screw on each side of the wheel.

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Step 3

Remove the chain from the rear wheel cog. Remove the rear wheel from the frame of the bike.

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Step 4

Remove the lockring on the back tire using a lockring wrench. To loosen the lockring twist the wrench clockwise.

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Step 5

Loosen the cog using a chain whip and adjustable pliers. Rap the chain whip around the cog. Push the chain whip handle down so that the cog twists counterclockwise.
It will take a lot of force to loosen the cog.

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