2578-2523 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN 2203E 2026-09-25) · extracted 2026-10-01

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN 2203E 2026-09-25); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the 2578-2523 model number is decoded

4T-2578/2523 is an NTN inch-series single-row tapered roller bearing: a separable cone-and-cup pair on the ABMA inch boundary plan, 28.575×69.85×23.812 mm (assembled width T), for a shaft of about 28.575 mm (1.125 in). Letter prefixes inherited from the inch convention mark the load family: LM reads as light-medium, HM as heavy-medium, LL as extra-light, J-prefixed codes as metric-envelope families — 2578 sits in the pure-numeric inch family. The 20.6 mm radial section over the 28.575 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. Housing fitment sequence for 4T-2578/2523: press the 2523 cup square into the 69.85 mm seat first, then bring the 2578 cone (on its 28.575 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Minimum load matters at speed: an unloaded 4T-2578/2523 run near 5,700 r/min lets the rollers skid; lightly spring-preload high-speed pair arrangements.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Hub and pinion positions of this 28.575 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-2578/2523.
• The pure-numeric inch family at 28.575 mm bore (69.85×23.812 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 2578/2523 reference at purchase.
• Fit selection follows the rotating ring: a rotating cone on a 28.575 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
• Shaft and housing fillets must clear the ring chamfers of 2578 and 2523; use undercut shoulders so the rings seat on the face, not on a radius.
• Fit selection follows the rotating ring: a rotating cone on a 28.575 mm shaft takes a k5/m5 seat, and a rotating cup reverses the logic — decide from the load diagram, not from habit.
• The 76.5/81.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-2578/2523; internal geometry legitimately differs between inch-series makers, so re-verify ratings, adjustment and the exact cone/cup references before substituting another brand on a rated drive.