The sweat is making your hand slip, the vein in your forehead is threatening to explode, and your tools are begging you to end it. Stuck fasteners or threaded components are relatively rare on well-kept bikes, but ask any busy shop mechanic and they’ll tell you an ultra-tight pedal, crank bolt, bottom bracket, thru-axle, or even cassette is a daily encounter.
In many ways, the methods for dealing with such tight threaded components overlap closely with those tips and tricks previously shared for removing rounded bolts. Sensible application of torque, perhaps some penetrating oil, and maybe a careful application of heat will often fix all but the most welded-on of tight threads. However, the process of undoing any stuck component can be nuanced, so the suggestions, tools, and techniques can vary. In this article, I’ll cover some broader elements along with a few common specifics.
Before we get started with this edition of Threaded, it’s critical to note that if done incorrectly, many of the things covered in this article can cause injury to body and/or bike. Many professional mechanics have proven methods, secret tricks, or just pure witchcraft for finding success, but such methods become vastly more time-consuming (and expensive) if someone else has previously tried and failed at the task. If you’re unsure, please consult a professional.
Prevention and technique
With most things maintenance-related, prevention is key. Bicycles don’t offer much protection from the elements; add in sweat plus the common use of dissimilar materials and you have a quick recipe for galvanic corrosion. Unless something specifically calls for a dry thread, then you should add a coating of anti-seize, grease, or thread-locker to keep corrosion away.
As if corrosion weren’t enough, modern performance-oriented bicycles now feature many softer materials in an effort to save weight. Fine-thread aluminium bolts and lockrings are common and more susceptible to galling, where the soft threads effectively bind under extreme torque (this is what causes SRAM DUB cranks to become stuck, addressed in a sidebar later).
It’s also common to experience fasteners that were overtightened from the factory or by the previous person to touch them. While not always the case, much of this is preventable by following torque recommendations (and applying corrosion-preventative lubricant to the thread.)
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