How to Replace a Bottom Bracket on a Bicycle

はじめに

Bottom bracket broken and can't ride your bike? This guide will walk you through how to remove the bottom bracket, how to grease the threads of the new bottom bracket, and then how to reinstall the bottom bracket. This instruction manual is specific to square taper bottom brackets.

必要な工具と部品

手順1 Bottom Bracket

How to Replace a Bottom Bracket on a Bicycle, Bottom Bracket: 手順 1、 1の画像 1

Flip the bike so that it is resting on the handle bars and seat.

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手順2

How to Replace a Bottom Bracket on a Bicycle: 手順 2、 3の画像 3

Take out the bolts on the base of the crank using an allen wrench that fits the bolt.
Do this to both sides. Set the bolts aside.

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手順3

How to Replace a Bottom Bracket on a Bicycle: 手順 3、 3の画像 3

Screw the crank puller into the place where the bolts used to be.
Tighten the crank puller until it pulls the crank off the bike.
Repeat for the other side.
Set aside the cranks, keeping track of which side each one goes on.

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手順4

Go to the side that does not have the drive train. This side must be completed first!
Insert the bottom bracket tool into the bottom bracket. Use the tool to turn the bottom bracket counter clock wise. It will be difficult to turn, but enough force will get it to turn.
Completely remove the small side of the bottom bracket.
Repeat for the side with the drive train, except turn the bottom bracket tool clockwise this time.

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手順5

Pull out the damaged bottom bracket from the drive train side.
Discard the broken bottom bracket.

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手順6

Get the new bottom bracket.
Notice the left (L) and right (R) markers on the part. This will help guide you when inserting the part.
Grease both parts of the threads using the paint brush. Apply enough grease so that the threads are evenly coated.

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手順7

How to Replace a Bottom Bracket on a Bicycle: 手順 7、 3の画像 3

Insert the bottom bracket from the drive side of the bike with the larger side facing your hand.
Gently screw in the second set of threads on the other side with your fingers.

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手順8

Use the bottom bracket tool to screw in the larger side (drive side) of the bottom bracket. Make sure to screw it in counter clock wise.
Screw the bottom bracket in all the way, but make sure not to tighten it down.
Repeat for the smaller side, except screw the bottom bracket in clock wise.
Tighten both sides down with the bottom bracket tool.

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手順9

Put the cranks back on their corresponding sides.
Make sure the chain goes back around the chain ring.
Put the bolts back through and tighten them into place with the allen wrench used earlier.