NU321 NA ZKL | Cylindrical Roller Bearing | 105X225X49

Check the part number stamped on the bearing's outer ring or shield — this usually follows a standard format (e.g. 6205-2RS). If the marking is worn, measure the bore diameter, outer diameter and width, then use our cross-reference tool or send the dimensions to our technical team and we'll identify it.

Sealed bearings (2RS / RS) have rubber contact seals that keep out dust, moisture and contaminants — better for washdown or dirty environments. Shielded bearings (ZZ) use non-contact metal shields, allowing lower friction and higher speeds, but offer less protection against ingress.

Load rating depends on the application: radial load, axial (thrust) load, speed and expected service life. The dynamic load rating (Cr) applies to rotating applications; the static load rating (Cor) applies to stationary or slow-moving loads. If you're unsure, share your application details — RPM, load direction and duty cycle — and we'll size it for you.

Yes — most standard metric bearings (deep-groove ball bearings, etc.) are dimensionally interchangeable across major manufacturers when the ISO part number matches (a 6205 is a 6205 regardless of brand). Precision class and material spec can still vary, so check the datasheet if tolerance is critical.

Most of our stocked bearings are supplied to ISO Normal (P0) tolerance — the standard class for general industrial use. Tighter precision classes (P6, P5 and above) are available to order; tell us your application and we'll confirm what's achievable.

Yes — stainless and corrosion-resistant options are available across several lines, suited to food, marine and washdown environments. Let our team know your conditions and we'll recommend the right grade.

Stocked lines dispatch the same working day when ordered before 3pm. Special-order and non-standard items vary by manufacturer — we'll confirm a firm lead time as soon as you enquire.

Yes — material certificates and traceability documentation can be supplied for regulated industries such as aerospace, food and pharmaceutical. Please request this at the time of ordering.