Sheave and Drum Ratios

Sheave and Drum Ratios
Construction* Suggested
D/d Ratio**
Minimum
D/d Ratio**
6x 7 72 42
19x 7 or 18 x 7 Rotation Resistant 51 34
6x 19 S 51 34
6x 25 B Flattened Strand 45 30
6x 27 H Flattened Strand 45 30
6x 30G Flattened Strand 45 30
6x 21 FW 45 30
6x 26 WS 45 30
6x 25 FW 39 26
6x 31 WS 39 26
6x 37 SFW 39 26
6x 36 WS 35 23
6x 43 FWS 35 23
6x 41 WS 32 21
6x 41 SFW 32 21
6X 49 SWS 32 21
6X 43 FW (2 op) 28 18
6x 46 SFW 28 18
6x 46 WS 28 18
8x 19 S 41 27
8x 25 FW 32 21
6x 42 Tiller 21 14

* WS -Warrington Seale
FWS – Filler Wire Seale
SFW – Seale Filler Wire
SWS – Seale Warrington Seale
S – Seale
FW – Filler Wire

**D=tread diameter of sheave
d= nominal diameter of rope

To find any tread diameter from this table, the diameter for the rope construction to be used is multiplied by its nominal diameter (d). For example, the minimum sheave tread diameter for a 1/2″ 6 x 21 FW rope would be 1/2″ (nominal diameter) x 30 (minimum ratio) or 15″.

NOTE: These values are for reasonable service. Other values are permitted by various standards such as ANSI, API, PCSA, HMI, CMAA, etc. Smaller values affect rope life.

Need Wire Rope?  Get a Quote!

Request an Estimate