The Stumpjumper is a high-end range of mountain bikes manufactured by American company Specialized Bicycle Components, Inc., known simply as Specialized. It first appeared in 1981, being the world’s first major production mountain bike model. As of March 2013, the FSR is the latest incarnation of the range.
Insert the non-splayed end of the standard headset cup removal tool through the orifice in which the bearing sits. Specialized recommends a standard tool for this job, rather than a headset press. It is essentially a hollow metal cylinder, often aluminium, with four or more moveable, splayed lugs at one end, formed by cuts from the end down the cylinder body some way. You can make your own, if you wish, from an old seat post or similar piece of tubing.
Pull the non-splayed end of the tool until you hear a distinctive metallic “pop” sound. This is the noise the removal tool lugs make when they have brushed past the bearing, expanded and engaged behind the bearing. At this point, stop pulling. Ensure even engagement, which is often apparent by the position of the removal tool, which should not be skewed in any way. With the lugs of the tool in place, the non-splayed end will now be able to accept a force to unseat the bearing.
Tap the non-splayed end of the tool with a mallet with purpose but care. The bearing should emerge without much effort. Usually, little force is needed to remove the bearing, although it is more than can be applied manually, for most people.
Pull out the removal tool and insert it the other way. Follow the same procedure as before to engage the other bearing. Tap this out too with the mallet.
Avoid contact between the headset removal tool and the frame inserts, or alloy cup interfaces. They are physically bonded into the frame and could be easily damaged.
Tips and warnings
- Avoid contact between the headset removal tool and the frame inserts, or alloy cup interfaces. They are physically bonded into the frame and could be easily damaged.