What are the torque specs of your U-Bolts?

Always use manufacturer recommended torque specifications!

Compared to other fasteners, recommended torque levels for U-bolts are significantly lower. This is due mainly to the stress concentration effect of the U-bolt bend itself, the dynamic loading that the spring transmits to the U-bolt and the difficulty of achieving even stress on both legs of a U-Bolt.

Recommended torque levels from the vehicle or suspension manufacturer should always be used where possible. If these specifications are unknown, the following chart can be used as a guide at your own risk.

Grade  5

• 3/8 (24 threads per inch, SAE) – 30 ft⋅lbf max
• 7/16 (20 threads per inch, SAE) – 45 ft⋅lbf max
• 1/2 (20 threads per inch, SAE) – 65 ft⋅lbf max
• 9/16 (18 threads per inch, SAE) – 90 ft⋅lbf max

Grade 8

• 5/8 (18 threads per inch, SAE) – 170 ft⋅lbf max
• 3/4 (16 threads per inch, SAE) – 300 ft⋅lbf max
• 7/8 (14 threads per inch, SAE) – 480 ft⋅lbf max
• 1 (14 threads per inch, SAE) – 740 ft⋅lbf max
• 1-1/8 (12 threads per inch, SAE) – 1300 ft⋅lbf max
• 1-1/4 (12 threads per inch, SAE) – 1780 ft⋅lbf max

 

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