Home › AS568-249
AS568-249 O-Ring Size
200 series · 1/8" cross section · General purpose, cylinders
Inside diameter × cross section
123.42 × 3.53 mm
4.859″ × 0.139″ ·
outside diameter 130.48 mm (5.137″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 4.859″ | 123.42 mm |
| Cross section (CS) | 0.139″ | 3.53 mm |
| Outside diameter (OD) | 5.137″ | 130.48 mm |
Outside diameter is not measured, it is derived: OD = ID + 2 × CS.
If your measured OD disagrees with this, trust the ID and cross section — measuring
across the outside of a flexible ring is the least reliable of the three.
If you measured a used one
A ring pulled out of service will measure smaller than 123.42 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -249 is very likely still the correct part. Ordering the size your worn ring measures is how the same failure repeats. More on this →
Nearby sizes in the 200 series
These share the same 1/8" cross section, so if the thickness is right but the diameter is off, your ring is probably one of these.
| Dash | ID (mm) | ID (in) | OD (mm) |
|---|---|---|---|
| -248 | 120.24 | 4.734″ | 127.3 |
| -250 | 126.59 | 4.984″ | 133.65 |
| -247 | 117.07 | 4.609″ | 124.13 |
| -251 | 129.77 | 5.109″ | 136.83 |