Tackle Block Information
Sheave Size & Wire Rope Strength
Strength Efficiency
Bending wire rope reduces its strength. To account for the effect of bend radius on wire rope strength when selecting a sheave, use the table below:
| Ratio A | Strength Efficiency Compared to Catalog Strength In % |
| 40 | 95 |
| 30 | 93 |
| 20 | 91 |
| 15 | 89 |
| 10 | 86 |
| 8 | 83 |
| 6 | 79 |
| 4 | 75 |
| 2 | 65 |
| 1 | 50 |
Example:
To determine the strength efficiency of 1/2” diameter wire rope using a 10” diameter sheave:
To determine the strength efficiency of 1/2” diameter wire rope using a 10” diameter sheave:
Refer to ratio A of 20 in the table then check the column under the heading “Strength Efficiency Compared to Catalog Strength in %”…91% strength efficiency as compared to the catalog strength of wire rope.