Fit your MTB bottom bracket

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Used to MTB method source of best bike us is the best cycling. Three standard pedals exist: the BSA, Press fit or BB30. For the record, know that the BB30 is the oldest standard of the three. The BSA was invented by Cannondale and is now used in MTB bottom bracket mainly by Specialized (and Cannondale of course). The Press fit is the latest in date. Finally, note that the BSA and Press-fit share the same set of cranks, the latter is a case apart.

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Remove the cranks

Let’s start by removing the cranks. On most brands, we will find an extractor screw on the opposite side of the tray. Often, just loosen it and the crank is automatically extracted. If the pedal is not equipped with extractor, then it is necessary to bring a good crank pull the old way.

At Shimano and some other more confidential brands, we find a different editing. It is necessary to loosen a screw located at the end of the axis, as well as the two clamping screws perpendicular to the axis of the pedals, Shimano is in this configuration.

On all BB30 cranks, we find the mounting system with the extractor screw, except that the latter is located on the plateau side. The procedure for disassembly remains the same as that seen above.

Assemble/disassemble the different housings

The standard BSA enclosures offer a screwed system; note that they unscrew themselves clockwise on the shelf side and counterclockwise on the opposite side. Regarding the tool to be used, pay careful attention to the mark of the case that you have mounted in order to use the proper tool. Indeed, each case brand has its own grooves, so you need the tool that fits. Yes, otherwise it would be too simple … This case exists in 73 mm (mainly used for endure bikes) or 83 mm (for DH).

The Press fits and BB30 cases are mounted on the same principle, “in force”. Suddenly, their handling requires little more tools … Regarding the Press fit, it must be pushed by inserting a hunt from the inside, to come shock (hitting the hunt) to the outside. Repeat the operation on each side.

For the BB30, the same method can be used except that on this standard, the bearings are placed on the frame. It is, therefore, necessary to shock directly MTB bottom bracket on the bearings to remove the housing. Whether with the Press fit or the BB30, remove the case means the death of it because it comes banging on the bearings, and as you say they do not appreciate this kind of treatment… How to choose your mask for MTB? It is the best MTB method to you.

Note that, like the BSA standard, there are also two possible case widths: 92 and 104 mm.


To mount a new BSA case, it is simply necessary to perform the reverse operation to that performed during disassembly. Do not forget to put a little grease on the thread, and then screw the case back into the frame. The first part of the screwing is done by hand and, once everything is in place, you finish tightening with a tool. This offers the advantage of preserving the threading by ensuring that everything is in place. Be very careful about this because it is easy to put a case through and damage the frame thread. What constitutes a small disaster? Attention also to the direction of screwing, and to put well each part of the box on which it corresponds to the frame (right to left and left to the left, logical). We always start editing by the side tray, often called “drive side” on the housing.

For the other two standards, you will need specific tools (such as during assembly), a press. Note that it is sometimes possible to use the same one that you use to mount the direction games. Apply grease to the frame; the grease is always useful on every point of contact, often avoiding creaky noise like crunches. To fit the bearings, I advise you to do them one after the other, it will avoid getting a wrong ride. Best Mountain bike buying advice – Everything you need to know-


Once the casing is well put in place, it’s time to rebuild the cranks. Again, put a little grease on the axis of the cranks, put it in the housing and tighten the crank opposite to block everything.


The interview

When it comes to maintenance, there is not much going on behind the boxes. Most of them are mounted with sealed bearings and these are impossible to regress. Only the BSA standard allows minimum maintenance, i.e. the lubrication of the threads and the verification of the tightening. As mentioned above, the Press fit and BB30 enclosures are dead once they have been dismantled, so it is not even worth thinking about servicing them. You can simply clean and grease the axis of the cranks (for all the cranks), which will avoid unpleasant noises like the famous crunches.

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