NA4904-XL
Holding a bearing marked NTN NA4904 or KOYO NA4904 or NADELLA NA 4904? Ours is NA4904-XL — the same seat size, the same type and the same sealing and clearance design.
What this bearing is
NA4904-XL is a needle roller bearing with a 20 × 37 × 17 mm seat, execution: open. The manufacturer's cross-reference catalogue confirms full interchangeability for 3 designations, including NTN NA4904, KOYO NA4904, NADELLA NA 4904.
Designation equivalents
⌀20 × 37 × 17 mm
Before you replace it
This is a dimensional and design equivalent: the same seat size, the same bearing type and the same sealing and clearance design. It is not the same product — load ratings, tolerance class and grease may differ between manufacturers. For duty close to the limits or a critical application, check the datasheet of the specific design.
The same seat in another execution
These items share the mounting size and have cross-reference tables of their own. They differ in sealing, clearance or cage — exactly what decides how the bearing behaves in the seat.
Where these equivalents come from
The base number of a standard bearing is an ISO standard — 6205 is 6205 at every manufacturer. Only the suffixes describing the design differ, and those are what we translate: shields, contact seals, cage and radial clearance. Designations that mean different things at different makers are deliberately omitted.