Breakaway Torque vs. Running Torque

When you tighten or loosen a fastener, the torque is not constant. Understanding breakaway torque vs running torque helps you interpret test data, choose lubricants or threadlockers, and verify that a joint is behaving as expected in service.

What Is Breakaway Torque?

Breakaway torque is the torque required to start a fastener moving from a fully seated or static condition. It is the peak value needed to overcome static friction and any locking features before rotation begins. For a concise definition and examples, see our glossary entry on Breakaway Torque.

What Is Running Torque?

Running torque is the torque required to keep the fastener turning once it is already in motion. It reflects dynamic friction in the threads and under the head or nut after breakaway has been overcome. Learn more in our glossary entry on Running Torque.

Why the Difference Matters

• Performance of locking features: Prevailing torque nuts, nylon inserts, and some threadlockers are often specified in terms of both breakaway and running torque.
• Service checks: Comparing breakaway torque to the original tightening specification can help indicate whether a joint has loosened or yielded.
• Fastener selection: Understanding torque behavior helps you match bolts, nuts, and washers to your lubrication and locking strategy.

For critical joints that use prevailing torque hardware or threadlocking compounds, always refer to the specified breakaway torque and running torque values so your assemblies built with Springs Fastener components perform consistently over their service life.