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Class 8.8 & Class 10.9 · Nm and ft-lb
Metric Bolt Torque Chart — Class 8.8 & Class 10.9
Metric bolt torque values for Class 8.8 and Class 10.9 fasteners, dry and lubricated, in Nm and ft-lb for M6 through M24 bolts. Always verify against OEM specifications for critical diesel engine fasteners.
Metric Torque Values — Class 8.8 & Class 10.9
Values in Nm / ft-lb · Lubricated = 75% of dry · Anti-seize = 65% of dry
| Bolt Size | 8.8 Dry | 8.8 Oiled | 10.9 Dry | 10.9 Oiled |
|---|---|---|---|---|
| M6 × 1.0 | 10 Nm / 7 ft-lb | 8 Nm / 6 ft-lb | 14 Nm / 10 ft-lb | 11 Nm / 8 ft-lb |
| M8 × 1.25 | 25 Nm / 18 ft-lb | 19 Nm / 14 ft-lb | 35 Nm / 26 ft-lb | 26 Nm / 19 ft-lb |
| M10 × 1.5 | 49 Nm / 36 ft-lb | 37 Nm / 27 ft-lb | 70 Nm / 52 ft-lb | 53 Nm / 39 ft-lb |
| M12 × 1.75 | 86 Nm / 63 ft-lb | 64 Nm / 47 ft-lb | 120 Nm / 89 ft-lb | 90 Nm / 66 ft-lb |
| M14 × 2.0 | 135 Nm / 100 ft-lb | 101 Nm / 75 ft-lb | 190 Nm / 140 ft-lb | 143 Nm / 105 ft-lb |
| M16 × 2.0 | 210 Nm / 155 ft-lb | 158 Nm / 116 ft-lb | 295 Nm / 218 ft-lb | 221 Nm / 163 ft-lb |
| M18 × 2.5 | 290 Nm / 214 ft-lb | 218 Nm / 161 ft-lb | 410 Nm / 302 ft-lb | 308 Nm / 227 ft-lb |
| M20 × 2.5 | 410 Nm / 302 ft-lb | 308 Nm / 227 ft-lb | 580 Nm / 428 ft-lb | 435 Nm / 321 ft-lb |
| M22 × 2.5 | 550 Nm / 406 ft-lb | 413 Nm / 305 ft-lb | 780 Nm / 575 ft-lb | 585 Nm / 431 ft-lb |
| M24 × 3.0 | 710 Nm / 524 ft-lb | 533 Nm / 393 ft-lb | 1000 Nm / 738 ft-lb | 750 Nm / 553 ft-lb |
Nm to ft-lb conversion — multiply Nm × 0.7376 to get ft-lb. Divide ft-lb by 0.7376 to get Nm.
Lubricated torque — approximately 75% of dry torque. Anti-seize reduces torque by approximately 35%.
Class 12.9 — the highest metric grade, used on critical diesel engine fasteners. Torque values are approximately 25% higher than Class 10.9. Full Class 12.9 table is in the premium Bible.
OEM always wins — these are general reference values. Always use OEM specifications for head bolts, main caps, rod bolts, and other critical fasteners.
Pro tip: Class 12.9 torque values are ~25% higher than Class 10.9. Full Class 12.9 table in the premium Bible.
Need engine-specific metric torque sequences?
The full Bible includes complete torque sequences for European and Asian diesel engines — with angle torque specs, TTY procedures, and VIN-specific variants for metric-fastener platforms.
Unlock the Full Bible — $9.95Metric Torque — FAQ
What is the torque spec for an M12 × 1.75 Class 10.9 bolt?
An M12 × 1.75 Class 10.9 bolt torques to 120 Nm (89 ft-lb) dry, or 90 Nm (66 ft-lb) lubricated. Always verify against OEM specifications for critical diesel engine fasteners.
What is the difference between Class 8.8 and Class 10.9 metric bolts?
Class 10.9 bolts are stronger than Class 8.8 and require approximately 40% more torque for the same bolt size. Class 10.9 bolts are used in high-stress diesel applications such as structural mounts, suspension, and drivetrain components.
How do I convert Nm to ft-lb for metric bolt torque?
Multiply Nm by 0.7376 to get ft-lb. For example, 120 Nm × 0.7376 = 88.5 ft-lb. Or divide ft-lb by 0.7376 to get Nm.
What metric bolt sizes are most common on diesel engines?
M8, M10, and M12 are the most common metric bolt sizes on diesel engines. M6 is common for sensor threads and small brackets. M14 and M16 appear on larger structural components, exhaust manifolds, and turbocharger mounting.
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