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AS568-166 O-Ring Size
100 series · 3/32" cross section · Hydraulics, pumps, valves
Inside diameter × cross section
171.12 × 2.62 mm
6.737″ × 0.103″ ·
outside diameter 176.35 mm (6.943″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 6.737″ | 171.12 mm |
| Cross section (CS) | 0.103″ | 2.62 mm |
| Outside diameter (OD) | 6.943″ | 176.35 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 171.12 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -166 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 100 series
These share the same 3/32" 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) |
|---|---|---|---|
| -165 | 164.77 | 6.487″ | 170.0 |
| -167 | 177.47 | 6.987″ | 182.7 |
| -164 | 158.42 | 6.237″ | 163.65 |
| -168 | 183.82 | 7.237″ | 189.05 |