What should hitch bolts be torqued to?
There isn’t a universal torque for hitch bolts; torque them to the specification provided by the hitch or vehicle manufacturer.
In practice, installation instructions from hitch kits and vehicle manuals spell out the exact torque values based on bolt size, grade, and whether threads are lubricated. The ranges below are general references to help when a specific spec isn’t immediately available, but you should verify the exact figure for your hardware.
Typical torque ranges by bolt size (SAE/imperial)
Below are common reference ranges for hitch hardware. Actual values depend on bolt grade, lubrication, and the material you’re threading into. Use the manufacturer’s spec whenever possible.
- 1/2 in, UNC, Grade 8: 110–125 ft-lbs (150–170 N·m)
- 9/16 in, UNC, Grade 8: 140–170 ft-lbs (190–230 N·m)
- 5/8 in, UNC, Grade 8: 170–210 ft-lbs (230–285 N·m)
- 3/4 in, UNC, Grade 8: 250–300 ft-lbs (340–405 N·m)
Note: These ranges are typical for robust hitch installations. Always confirm the exact torque spec provided with your hitch kit or vehicle manual, especially if you use lubricants or thread lockers, which can significantly affect clamping force.
Typical torque ranges by bolt size (metric)
For metric hitch bolts, the exact specification will come from the kit or vehicle; the ranges below cover common sizes and grades found in aftermarket setups.
- M12 x 1.25 or 1.75, Grade 8.8: 70–100 Nm (52–74 ft-lbs)
- M14 x 2.0, Grade 8.8: 110–150 Nm (81–110 ft-lbs)
- M16 x 2.0, Grade 8.8: 170–230 Nm (125–170 ft-lbs)
Again, these figures are guideposts. Always follow the exact torque specification from the hitch manufacturer or vehicle documentation to ensure proper clamping and safety.
Factors that influence the required torque
Several variables can shift the needed torque, so consider the following when tightening hitch bolts:
- Thread lubrication: lubricated threads require lower torque to achieve the same clamping force as dry threads.
- Thread engagement and material: deeper engagement or softer frame material can alter the torque needed.
- Washer presence and hardware type: locking washers, lock nuts, or threadlocker can change the effective friction.
- Number of bolts and symmetry: evenly distributed loading across all bolts improves stability and may affect the torque target for each bolt.
- Verification: many installations require re-torque after an initial drive (often after 50–100 miles) to account for settling and any relaxation of the connection.
For best results, consult the exact torque spec for your specific hitch kit and vehicle, follow the installation steps precisely, and use a calibrated torque wrench to verify each bolt is tight to the recommended value.
How to apply the torque correctly
Follow these general steps to ensure you torque hitch bolts properly, with emphasis on safety and accuracy.
- Assemble the hitch according to the manufacturer’s instructions, using new bolts if recommended.
- Clean threads and apply the specified lubricant or threadlocker if required by the kit.
- Install bolts hand-tight, then tighten in a cross-pattern (if multiple bolts) to the specified torque using a calibrated torque wrench.
- After the initial drive, re-check torque to account for settling and ensure all bolts remain at the required specification.
Following these steps helps ensure a secure, long-lasting hitch installation and reduces the risk of loosening during towing.
Summary
Hitch bolts do not have a single universal torque. Always torque to the value specified by the hitch manufacturer or vehicle maker for your bolt size and grade. If you must use reference ranges, expect roughly 110–125 ft-lbs for 1/2" Grade 8 bolts, up to 170–210 ft-lbs for 5/8" Grade 8 bolts, and corresponding metric ranges around 70–100 Nm (M12), 110–150 Nm (M14), and 170–230 Nm (M16). Lubrication, thread condition, and mounting material all affect the required torque, and re-torquing after a short break-in period is often advised. When in doubt, rely on the exact spec from your hardware and vehicle documentation.
