31328XU bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); 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 31328XU model number is decoded

In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 31328XU denotes the steep-angle 31300 family for high axial load share of metric tapered roller bearings, 140 mm bore, 300 mm outside diameter and 77 mm assembled width T (5.512 × 11.811 × 3.031 in) to the ISO 355 boundary plan. The last two digits 28 are the ISO bore code, ×5 = 140 mm (codes 00–03 use the 10/12/15/17 exception table) under the ISO 355 numbering; the 77 mm value printed here is T, the width of the fully assembled cone-plus-cup set, not the inner-ring width alone. A tapered roller bearing reacts combined radial and one-direction axial load; NTN mounts 31328XU cone and cup separately and adjusts end play or preload against a second bearing, so the arrangement locates the shaft in both directions. Speed planning uses both catalogue columns: grease 1,300 r/min is the cage/rib mechanical ceiling for 31328XU, oil 1,700 r/min is available with circulating oil — a 400 r/min margin at this size. Fillet radii must clear the ring chamfers of the 300 mm cup and 140 mm cone; use undercut shoulders so the rings seat fully rather than bridging on a shaft radius.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• At 140 mm bore the 31328XU set is adjusted with hydraulic nuts on large mill and wind positions; follow the drive-up angle/end-play procedure, because manual torque methods cannot control preload at the 760 kN C level.
• The steeper contact angle of the steep-angle 31300 family for high axial load share raises axial capacity but lowers the speed ceiling against a 302/322 bearing at 140 mm bore; do not swap to the lighter family without re-checking the 1,300 r/min grease limit and the thrust load split.
• Open 31328XU units have no seals: a wheel-hub or gearbox application needs external sealing or the 1,300 r/min grease figure is meaningless once water reaches the cone rib.
• Minimum load matters at high speed: an unloaded 31328XU at a large fraction of 1,300 r/min lets rollers skid and smear the cone rib; spring-preload lightly loaded pair arrangements.
• Do not confuse T (77 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
• The 760/905 kN ratings and 87 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 31328XU (ISO 355 7GB); internal geometry legitimately differs between manufacturers, so re-verify ratings, adjustment and suffix before substituting another make on a rated drive.