Sheave- and Drum Dimensions

Sheave Dimensions 

We recommend only sheaves made of steel or cast steel. The following are recommended values:

Groove radius (r):
Minimum 0.53 to 0.535 x d
Maximum 0.55 x d
Recommended: ≈ 1% over the actual wire rope diameter

Groove depth (h):
Recommended: ≈ 1.5 x d or d x √2

Sheave throat angle:
For normal applications use 35° to 45° opening. Applications with deflection angles of more than 1.5° use 60° opening. Opening angles below 35° must be avoided.

Sheave hardness:
As the hardness of the single wires in a rope can be approximated to be 50-55 RC, the hardness on the sheave surface must be min. 35 RC, better is 40-45 RC.

D/d ratios:
Depending on the actual equipment and usage of wire rope in hoisting- or pulling applications the following D/d ratios are suggested:

Min. D/d ratio
6×19 S IWRC 34
6×26 WS IWRC 30
6×25 FW IWRC 26
6×36 WS IWRC 23
Python® Multi 20
Python® Super 8 20
Python® Power 9 26
Python® Ultra 26
8×36 18
19×7 / 18×7 34
19×19 20
Python® Compac 18 20
Python® Hoist 20
Python® Compac 35 20

Drum Dimensions

Generally, we recommend grooved drums only. The rope is spooled properly and positively. Depending on the drum/rope diameter relationship helix-grooved drums can be used for up to 3 layers without excessive rope wear. For applications with more than 3 layers (e.g. Mobile cranes) we recommend ‘Lebus’ grooving.

It has to be remembered, however, that rope service life on multiple layer drum systems will always only be a fraction of that compared with single layer helix-grooved drums.

Important: for standard applications the drum grooving should be left hand to accomodate standard right hand lay ropes!

Groove radius (r):
Minimum 0.53 to 0.535 x d
Maximum 0.55 x d

Pitch diameter (p):
The pitch dia. has to be chosen in accordance with the groove radius. Under no circumstance should the pitch dia. be smaller than:
• Minimum 2.065 x groove radius
• Maximum 2.18 x groove radius

If these values are applied to single layer grooved drums the maximum permissible rope-deflection angle for regular wire rope constructions is 4°. For non rotating /rotation-resistant ropes the maximum permissible deflection angle is 1.5° only.

Groove depth (h):
Minimum ≥ 0.374 x d for helically grooved drums