Home › AS568-366
AS568-366 O-Ring Size
300 series · 3/16" cross section · Heavy hydraulics, higher pressure
Inside diameter × cross section
183.51 × 5.33 mm
7.225″ × 0.21″ ·
outside diameter 194.18 mm (7.645″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 7.225″ | 183.51 mm |
| Cross section (CS) | 0.21″ | 5.33 mm |
| Outside diameter (OD) | 7.645″ | 194.18 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 183.51 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -366 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 300 series
These share the same 3/16" 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) |
|---|---|---|---|
| -365 | 177.16 | 6.975″ | 187.83 |
| -367 | 189.86 | 7.475″ | 200.53 |
| -364 | 170.81 | 6.725″ | 181.48 |
| -368 | 196.21 | 7.725″ | 206.88 |