# ISO 21771:2007 — Withdrawn and superseded ISO standards

For ISO 21771:2007, item title is Gears — Cylindrical involute gears and gear pairs — Concepts and geometry; status code is 9599; successor is ISO 21771-1:2024; withdrawn / published date is 2007-08-28, recorded from its source on 2026-08-05.

- **Identifier:** ISO 21771:2007 _(verified: appears in the quote below)_
- **Item title:** Gears — Cylindrical involute gears and gear pairs — Concepts and geometry _(verified: appears in the quote below)_
- **Status code:** 9599 _(verified: appears in the quote below)_
- **Successor:** ISO 21771-1:2024
- **Withdrawn / published date:** 2007-08-28 _(verified: appears in the quote below)_

## What the source says

> 35989,IS,,ISO 21771:2007,Gears — Cylindrical involute gears and gear pairs — Concepts and geometry,Engrenages — Roues et engrenages cylindriques à développante — Concepts et géométrie,2007-08-28,1,['21.200'],ISO/TC 60/SC 1,9599,[10361],[84949],['en'],83,"<p>ISO 21771:2007 specifies the geometric concepts and parameters for cylindrical gears with involute helicoid tooth flanks. Flank modifications are included. It also covers the concepts and parameters for cylindrical gear pairs with parallel axes and a constant gear ratio, which consist of cylindrical gears according to it. Gear and mating gear in these gear pairs have the same basic rack tooth profile.</p>"

## Source

- https://isopublicstorageprod.blob.core.windows.net/opendata/_latest/iso_deliverables_metadata/csv/iso_deliverables_metadata.csv

Last verified: 2026-08-05. Review by: 2027-02-01.
Part of [Withdrawn and superseded ISO standards](https://referencesource.org/iso-standard-supersessions/).