[Tech Corner] How To Install Press Fit Bottom Brackets

[Tech Corner] How To Install Press Fit Bottom Brackets

16/12/2015
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16/12/2015

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In the last years most bike frame manufacturers have moved to press fit bottom brackets. The movement to press-fit has been both loved and loathed. The main reason is the creaky noises that sometimes emanate from the BB area when there is a build up of dirt and dust. We take a look at our test bikes bottom bracket and show the best way to prepare and install a press fit bottom bracket so that it doesn’t take on the dreaded creak.

Required : Bearing extractor, allen keys, grease, bike stand, bearing cup press.

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Everyone has an opinion, when asked how to not have to do this operation, the amusing suggestion that came back is unrepeatable and would start an internet comment war.

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The current setup is a BB30.

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We inspect the removal bolt for dirt and remove the chain.

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The self extracting crank bolt can be jammed in, don’t force it, just ease it out.

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It’s all about preparation, here we have a very dirty bottom bracket area. Time to clean up and remove the old one.

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Press fit works best when you clean the surfaces with a strong degreasing cleaner.

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Now clean we can be sure not to get stray dirt into the bearing area when working on it.

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We use a bearing extracting tool and soft rubber mallet and drive out the old bearings from the back side.

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You shouldn’t have to wail on it, the bearings will release themselves easily.

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Still in good working order but dirty.  If the bearings are rough or pitted, they need to be replaced.

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We remove the retaining clips.

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Now we thoroughly spray and clean the cup area, removing all signs of dust and dirt. The cups need to be exceptionally clean.

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We take a press-fit bottom bracket, in this case a BB30 to 24mm conversion.

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Apply a thin layer of grease to the outside surfaces of the cups and to the inner surfaces of the bottom bracket shell.  This will keep it creak free and makes installation a snap.

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We take our drive side bearing cup only and place it on the mounting tool and pass the tool through the frame.

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We then tighten the tool, and slowly drive the bearing race into the BB shell.

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The drive side bearing cup nestled into position.

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We follow the same procedure on the non-drive side of the frame. Note : we do each cup one at a time. This ensures that the bearings go in straight every-time.

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The non-drive side bearing cup in position.

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A small amount of grease is required to apply to the surfaces of the axle and the keyed interface that the non-drive side crank accepts.

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We place on one spacer for our chain line conversion.  This will vary with each bike and setup based off of whether you are using things like front derailleurs and/or chainguides which inherently make changes to your chainline.

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Insert the crankset.

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Place the other crank arm in position and tighten.

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Tighten the crank arms down, reassemble your drivetrain, give it a quick shifting check and you are done!

Notes: make sure that all surfaces are really dry and clean with no grease before starting. Press fit success and prevention of creaking can depend a lot on the tolerances of the frame and cups, in this case they are very tight so the likely-hood of creaking is low.

Mechanic Provided by : Punta Ala Trail Center

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