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Inch Sizes Standard Pilot Bore Timing Pulleys

Inch Sizes Standard timing pulleys are the basic type of pulleys for belts with trapezoidal profiles and inch pitch. Their design is according to ISO 5296.

They are made from steel, cast iron or aluminium alloy with a pilot bore, alternatively unbored.

The pulleys are supplied as a semi-finished product and the bore must be modified before mounting the pulleys on the shafts.

XL Inch Sizes

Tooth pitch: 5.080 mm
Teeth z = 10 - 72
Stand. diameters Dp (mm): 16.17 - 116.42

L Inch Sizes

Tooth pitch: 9.525 mm
Teeth z = 10 - 120
Stand. diameter Dp (mm): 30.32 - 363.83

H Inch Sizes

Tooth pitch: 12.700 mm
Teeth z = 14 - 156
Stand. diameter Dp (mm): 56.60 - 630.64

XH Inch Sizes

Tooth pitch: 22.225 mm
Teeth z = 18 - 120
Stand. diameters Dp (mm): 127.34 - 848.93

Pulleys Fields of Use

The XL, L, H, XH standard timing pulleys are designed for all types of XL, L, H, XH belts.

They are typically used in older machines with lower and medium performance, for example in packaging machines, in the ceramic, textile, food and tobacco industry and in many other machines.

In new applications, they are often replaced by HTD, STD or CTD profiles.

Pulleys Material

Steel, cast iron or aluminum alloy.

Other materials to order.

Parameter Standard
Surface roughness ISO 254
Balance quality grade VDI 2060, ISO 1940


Cast iron pulleys at v < 30 m/s must be balanced.

Pulleys Basic Profile

  • Pulley XL for belts XL with pitch 5.08 mm
  • Pulley L for belts L with pitch 9.525 mm
  • Pulley H for belts H with pitch 12.70 mm
  • Pulley XH for belts XL with pitch 22.25 mm

Pulleys Code Description

30 XL 037 (Type 6F, Al Alloy)

Code Part Description

Number of pulley teeth


Teeth pitch in mm and type of pulleys for belts STD


Width of the belt in inches × 1/100 (0,37" = 9,398 mm)


Type of construction

Al Alloy

Pulley material 

Documents for Download

Dimensions and Parameters of Inch Sizes Standard Pilot Bore Timing Pulleys - Preview

Dimensions and Parameters of Inch Sizes Standard Pilot Bore Timing Pulleys

TYMA CZ Data Sheets

Czech and English (PDF 1.90 MB)

Pulleys and Clamping Bushes - Preview

Pulleys and Clamping Bushes

TYMA CZ Catalogue

Czech and English (PDF 3.64 MB)