These are all dimension standards. They fix sizes and fits. They do not give you a load rating, a service life or a material. ISO 12240-4 also states that it does not cover rod ends made for direct connection to hydraulic cylinders.
ISO is the International Organization for Standardization, a global standards body. DIN is the German standards body.
What does each standard cover?
The status column reflects the ISO standard pages as they stood in October 2026.
| Standard | What it covers | What it does not cover | Status |
|---|---|---|---|
| ISO 12240-4:1998 | Sizes, tolerances and internal clearance for spherical plain bearing rod ends in several size series. The tolerances apply to finished rod ends, before coating, plating or splitting | Rod ends for airframes, and rod ends made for direct connection to hydraulic cylinders (stated in the standard's summary) | Published |
| DIN 648 | The older German name. Catalogues list the same parts as "DIN ISO 12240 (ex DIN 648)" | The withdrawal year is not given here. Check with DIN | |
| ISO 6982:1992 | Mounting sizes for hydraulic cylinder eyes, for interchangeability, sizes 10 to 320 | Withdrawn. Replaced by ISO 8132:2006 and ISO 8133:2006. The 1982 edition is also withdrawn | |
| ISO 8132:2022 | Mounting sizes for accessories on single-rod cylinders: the 16 MPa (160 bar) medium series to ISO 6020-1, and the 25 MPa (250 bar) series to ISO 6022 | How the part performs | Published April 2022. Marked "to be revised", with a draft of the next edition listed |
| ISO 8133:2022 | The same kind of accessories for 16 MPa (160 bar) compact cylinders to ISO 6020-2 | How the part performs | Published May 2022. Same status |
| ISO 8139:2026 | Mounting sizes for rod-end spherical eyes on pneumatic cylinders: the 1,000 kPa (10 bar) series to ISO 6432 and ISO 15552 | Published September 2026, edition 5. The 2018 edition is withdrawn |
Pressure units: 160 bar equals 16 MPa. Both are used on cylinder data sheets.
ISO 8132 and ISO 8133 identify accessories with codes from ISO 6099. For example, AP6 is a spherical rod eye with a female thread, AP4 is a plain rod eye with a female thread, and AP2 is a rod clevis with a female thread. The standards' summaries say they cover the dimensions of parts made to them, not how those parts perform.
Why does ISO 12240-4 exclude hydraulic cylinder rod ends?
The standard's summary states the exclusion but gives no reason. The most likely explanation is that cylinder accessories are covered by the cylinder standards instead. Accessories for standard hydraulic cylinders, such as rod ends, fall under DIN ISO 8132, and those standards describe mounting dimensions, not the quality or material of the cylinder. If a datasheet quotes ISO 12240-4 sizes for a part sold for a cylinder, ask which standard really applies.
What happened to ISO 6982?
It was withdrawn and replaced, twice.
ISO 6982:1982 was withdrawn and replaced by ISO 6982:1992, which was itself withdrawn. Its replacements are ISO 8132:2006 and ISO 8133:2006. Those were revised again in 2014 and 2022, and only the 2022 editions are current. Any document that still cites ISO 6982 as the current standard is out of date.
Two standards are current, and they split by cylinder series. ISO 8133 covers the 160 bar compact series. The 250 bar series is in ISO 8132. They are easy to mix up.
What do the standards not specify?
Materials, load ratings and service life.
DIN ISO 12240-4 rod ends are standardised for dimension series, dimensions, tolerances and radial bearing clearance. The standard deliberately leaves materials, sliding pairs and surface treatments open. Load ratings and service-life calculations are set by each maker, and one maker's definition may differ from another's. One bearing maker, National Precision, states that no industry standard governs the load capacity of spherical plain bearings. So when you compare two makers' ratings, start with their definitions (see Q1-07).
The standard has two dimension series: E, with a narrow installation width, and K, which is wider. For the exact series definitions, read the standard itself.
What about DIN 648 and ISO 12240-1?
DIN 648 is the name older catalogues use for what is now DIN ISO 12240-4. Distributors often list their rod ends under "DIN ISO 12240-4 (DIN 648)". For the year DIN 648 was withdrawn, check the DIN catalogue.
ISO 12240-1 covers the spherical plain bearing itself, not the rod end body. Hänchen refers to it for the clearance groups of bearings in forms E and W, the wider inner-ring forms used in hydraulic cylinders. Check the standard's scope and edition before you quote it.
How should you ask a supplier about standards?
Ask by name, table and edition.
"ISO compliant" tells you very little, because these are dimension standards. Ask which standard, which dimension table and which edition the part follows, and ask for the drawing. Many cylinders on construction and farm machinery are often built to the maker's own dimensions rather than to an ISO series. In that case the drawing governs.
Some suppliers say this themselves. SYZ's HCR range page advises buyers not to assume a general ISO or DIN compliance from a mention of a material or a grease nipple. It asks buyers to request the exact drawing and documents for their application.