ISO 155-2019 PDF

Full title and description

St ISO 155-2019 — Belt drives — Pulleys — Limiting values for adjustment of centres. This International Standard specifies limiting values for the relative axial and radial adjustment (centres) of two transmission pulleys and gives applicability to crowned pulleys, V-belt pulleys (single, multiple or joined), V-ribbed pulleys and toothed pulleys for synchronous belts.

Abstract

This standard defines permissible limits for the adjustment of centres between paired pulleys used in belt drive systems to ensure proper belt seating, load distribution and reliable transmission performance. It provides numeric limiting values and applies across common pulley types used with flat, V, V‑ribbed and synchronous belts.

General information

• Status: Published / Confirmed International Standard.
• Publication date: 26 March 2019 (ISO edition 4, 2019).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.220.10 — Belt drives and their components.
• Edition / version: Edition 4 (2019).
• Number of pages: 6 pages (concise technical leaflet).

Scope

Specifies the limiting values for the adjustment of centres of two transmission pulleys. Applicable to crowned pulleys for flat belts; grooved pulleys for V-belts (single, multiple or joined); grooved pulleys for V-ribbed belts; and toothed pulleys for synchronous belts. It is intended for use where accurate pulley alignment affects belt life, noise, tracking and transmission efficiency.

Key topics and requirements

• Numeric limiting values for axial and radial centre adjustment between paired pulleys.
• Application notes distinguishing crowned, V, V‑ribbed and toothed pulleys.
• Requirements to ensure correct belt seating and minimise uneven wear or premature failure.
• Guidance to support consistent assembly, inspection and maintenance of belt drives.
• Concise format intended to be used alongside dimensional and product‑specific standards for belts and pulleys.

Typical use and users

Used by mechanical designers, drivetrain engineers, maintenance and reliability teams, pulley and belt manufacturers, and standards committees. Typical applications include industrial power transmission systems, conveyor drives, automotive accessory drives, and any equipment where belt alignment affects performance and safety.

Related standards

Complementary ISO standards on belt drives and belt characteristics (for example standards covering belt dimensions, antistatic properties, synchronous belts and testing methods). This edition of ISO 155 (2019) replaces earlier editions such as ISO 155:1998. Users should consult belt‑type specific standards when applying pulley‑centre limits.

Keywords

belt drives, pulleys, centre adjustment, alignment limits, crowned pulley, V‑belt pulley, V‑ribbed pulley, synchronous belt, pulley alignment, transmission belts

FAQ

Q: What is this standard?

A: ISO 155:2019 is an International Standard that specifies limiting values for the adjustment of centres of two transmission pulleys to ensure correct belt engagement and reliable operation.

Q: What does it cover?

A: It covers allowable axial and radial misalignment limits (limiting values) for paired pulleys and states applicability to crowned pulleys for flat belts, grooved pulleys for V and V‑ribbed belts, and toothed pulleys for synchronous belts.

Q: Who typically uses it?

A: Mechanical designers, drivetrain and maintenance engineers, pulley and belt manufacturers, installation technicians and standards committees use this standard to verify acceptable pulley alignment and to reduce belt wear and failure risk.

Q: Is it current or superseded?

A: ISO 155:2019 is the current (2019) edition and replaces the withdrawn ISO 155:1998; the 2019 edition is published and confirmed as the active International Standard.

Q: Is it part of a series?

A: It is one of several ISO documents addressing belt drives and their components; related standards cover belt dimensions, testing, materials and special properties (users should consult belt‑type and product‑specific ISO standards alongside ISO 155).

Q: What are the key keywords?

A: Belt drives, pulleys, alignment, centre adjustment, crowned pulley, V‑belt, V‑ribbed, synchronous belt, limiting values.