Bearing Precision Class
How ISO 492 precision classes P0, P6, P5 and P4 line up against the ABEC and JIS systems, and which classes FULI supplies as standard or on request.
Precision class governs how tightly the bore, outside diameter, width and running accuracy are controlled — not the load rating. Three naming systems are in common use; this page lines them up from standard to highest.
Precision classes, standard to high (low to high accuracy)
| ISO 492 | ABEC (American) | JIS | Typical use |
|---|---|---|---|
| Normal / P0 | ABEC 1 | Class 0 | General industrial — motors, pumps, gearboxes, mounted units |
| P6 | ABEC 3 | Class 6 | Higher-speed or lower-vibration general machinery |
| P5 | ABEC 5 | Class 5 | Precision spindles, higher-speed motors |
| P4 | ABEC 7 | Class 4 | High-speed spindles, precision machine tools |
Exact bore, OD and running accuracy tolerance values for each class and bore size are set out in ISO 492 and the corresponding ABEC and JIS documents; request the inspection tolerance for your specific size and class on the quotation if you need the micron figures for a drawing or specification check.
What FULI supplies
P0 (standard, equivalent to ABEC 1) is the default across deep groove ball bearing, tapered roller bearing and insert bearing. P6 is available on request for general machinery needing tighter running accuracy; P5 is available on specific models — ask before specifying it on a drawing so availability and lead time can be confirmed for the exact size and quantity.
Send the model, class and quantity to sales@fuli-bearings.com or use the request a quote form.
FAQ
Is a higher precision class always better?
No. A higher class tightens bore, outside diameter and running accuracy tolerances for applications such as spindles and high-speed motors, but costs more and is unnecessary for general industrial use, where standard class (P0 / ABEC 1) is accurate enough and is what most catalog bearings are made to.
Are ISO and ABEC classes numerically identical?
They are closely aligned at each step (standard to standard, next grade to next grade) but are defined in separate standards documents with their own tolerance tables, so treat the pairing as a close correspondence for comparing specifications, not as two labels for one identical number.
Which precision class does FULI supply?
P0 (standard / ABEC 1) as the default across the catalog. P6 (ABEC 3) is available on request, and P5 (ABEC 5) on specific models — confirm availability for your exact model and quantity before specifying it.