P2 is the tightest class in ISO 492, corresponding to ABEC-9. Runout is around 1 µm on a 30 mm bore, the bore and OD tolerances are correspondingly tight, and the bearings are normally supplied as matched sets with a specified preload. It is used in metrology, aerospace gyros, ultra-precision machining and optical grinding.
At 1 µm bearing runout, the housing bore, the shaft seat, the shoulder squareness, the preload and the thermal gradient all become significant. A P2 bearing installed with a press and a hammer is a P0 bearing with a P2 price. These assemblies are built in clean conditions with controlled torque and measured afterwards.
P2 is not a stocked class. Most sizes are produced to order with a lead time measured in weeks, and the range of sizes is narrower than P4. For a repair, this is often the deciding factor: a P4 bearing available today usually beats a P2 bearing in six weeks.
| Also written | Class 2, ABEC-9, DIN P2 |
|---|---|
| Typical radial runout | Around 1 µm for a 30 mm bore |
| Price relative to P0 | 600–900% |
| Supply | Factory order, weeks of lead time |
| Pairing | Matched to preload, marked for mounting direction |
| Typical use | Metrology, aerospace, optical grinding, ultra-precision spindles |
| Environment | Temperature-controlled, often oil-air lubricated |
| Criterion | P4 | P2 | Special (e.g. P4S) |
|---|---|---|---|
| Radial runout | ~2 µm | ~1 µm | Agreed |
| Price | 300–450% | 600–900% | Quoted |
| Lead time | Days to weeks | Weeks | Weeks to months |
| Availability | Broad | Narrow | Single source |
| Typical use | Grinding, metrology | Ultra-precision, aerospace | Application-specific |
In the usual crosswalk, yes. Both represent the highest standard precision class, though the two standards are not numerically identical.
Yes, but only in a limited range of small and medium sizes, normally as a factory order.
Speed alone does not require P2. P4 with a good preload and oil-air lubrication runs at very high speed; P2 is about accuracy, not rpm.
Send the designation, the three dimensions and the quantity — we reply with price, brand options and lead time within 30 minutes on working days.