Tightening Torques & Widths Across Flats
Here you will find the tightening torques and spanner widths of the most common inch and metric screws on your bike. These specifications always refer to strength class 8.8 and the combination “steel-in-steel”, i.e. steel screw in steel housing.
Inch Screws
| Thread in Inches | Thread in Millimetres | UNC | UNF | Tightening Torque in Nm | Width across Flat in Inch |
|---|---|---|---|---|---|
| 1/4 | 6,35 | 20 | 28 | 8 | 7/16 |
| 5/16 | 7,94 | 18 | 24 | 16 | 1/2 |
| 3/8 | 9,53 | 16 | 24 | 25 | 9/16 |
| 7/16 | 11,11 | 14 | 20 | 45 | 11/16 |
| 1/2 | 12,70 | 13 | 20 | 75 | 3/4 |
| 9/16 | 14,29 | 12 | 18 | 80 | 7/8 |
| 5/8 | 15,88 | 11 | 18 | 150 | 15/16 |
Metric Screws
| Thread in Millimeters | Tightening Torque in Nm | Width across Flat in Millimeters |
|---|---|---|
| M4 | 2,9 | 7 |
| M5 | 6 | 8 |
| M6 | 10 | 10 |
| M8 | 25 | 13 |
| M10 | 49 | 17 |
| M12 | 86 | 19 |
| M22 | 550 | 32 |