The winter has been a long one, muddy trails and grime have left our bikes feeling neglected and creaky. The source of dreaded mystery cracking noises can be hard to identify, but often they come from broken bearings in the bottom bracket. These bearings have a hard life, sitting in an exposed position they are subjected to the worst of the weather, and for a regular rider are often destroyed within a cycling season. In this service guide we tell you how to exchange a GXP Bottom Bracket including bearings and how to mount the crank again afterwards.

Die Vielzahl an Tretlagern in immens.
With the variety of bottom bracket standards on the market it is not possible to explain every detail. Therefore, in this guide we will focus on the exchange of a GXP bottom bracket.




  • BB-Wrench Tool
  • torque wrench
  • Allen wrench

How to:

Jedem GXP-Lager liegen zwei Spacer. Bei SRAM gilt folgende Regel: bei 68mm Innenlagerbreite rechts und links je 1 Spacer, bei 73mm Breite werden keine Spacer benötigt.
Each GXP bottom bracket comes with two spacers. For SRAM the following rule applies: 68mm bottom brackets need one spacer left and right, 73mm bottom brackets don’t need any spacers.
Nach der Demontage der Kurbel wird das Innlager mit Hilfe des geeigneten Werkzeuges entfernt. Hier ist darauf zu achten das es sich um ein rechts- / links-Gewinde handelt.
After disassembly of the crank, the bottom bracket can be removed using the appropriate tool. Care should be taken as there is a right (non-drive side unscrews anti-clockwize) and left handed thread (drive side unscrews clockwize).
Nun sollten die Gewinde im Rahmen gereinigt werden.
Now, the thread should be cleaned in the frame.
Vor der Montage der neuen Lagerschale sollte diese gut gefettet werden.
Before installing the new bearing shell they should be well greased.
Nun kann diese wieder eingeschraubt werden. Die Pfeile auf der Lagerschale geben die Richtung vor. Das Drehmoment sollte zwischen 34,0 und 41,0 Nm.
Now this can be screwed in. The arrows on the bearing shell provide the direction. The torque should be 34.0 to 41.0 Nm.
Zum Schutz vor Dreck wird nun der mitgelieferte Staubdeckel aufgesetzt
To protect against dirt the supplied dust cover gets installed next, also some grease is recommended when fitting.
Auch die Achse des Innenlagers wird mit einer ordentlichen Packung Fett versorgt.
The axle of the Crank is supplied with neat package grease.
DIe Kurbel wird nun wieder eingesetzt.
The crank side of the axle gets pushed through the bearings.
Nun kann der linke Kurbelarm aufgesetzt werden. Wir empfehlen diesen zuerst mit der Nuss in der Hand und erst im Anschluss mit der Ratsche zu fixieren
Now, the left crank arm can be mounted. We recommend first applying the nut by hand and once it is on the thread correctly, carefully drive it home with a ratchet.
Die Kurbel wird mit 43,0 Nm arretiert.
The crank get’s locked firmly with a torque of 48.0 Nm.

Tips and Tricks:

  • Pay attention to the right-and left-hand thread!
  • Hollowtech 2 cranks are not compatible with GXP bearings.
  • Ceramic bearings must be regreased every 50h in dry conditions and right after a ride when it is wet – we recommend buying regular BBs.
  • Always check the chainring screws if you have a suspicious cracking noise.

Picutres: Christoph Bayer Words: Christoph Bayer / Trevor Worsey

Did you enjoy this article? If so, we would be stoked if you decide to support us with a monthly contribution. By becoming a supporter of ENDURO, you will help secure a sustainable future for high-quality mountain bike journalism. Click here to learn more.