UCP318 bearing: complete specifications & equivalents
The UCP318 is a JIS B 1559 radial bearing sized 90 x 190 x 96 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 96 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 158 kN |
| Basic static load rating C0 | 107 kN |
| Fatigue load limit Pu | 7.1 kN |
| Mass | 22000 g |
| Housing height H | 118 mm |
| Housing overall length L | 430 mm |
| Mounting bolt center distance J | 330 mm |
| Mounting hole diameter N | 33 mm |
| Manufacturer designation | UCP318 |
| Standard | JIS B 1559 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); 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.
Dimensions in inches & UCP-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 3.78 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 50 mm |
| Smallest bore in UCP-series | 12 mm |
| Largest outer diameter in UCP-series | 300 mm |
| Width range across UCP-series | 31–145 mm |
| Bore position in UCP-series (smallest first) | 18 of 25 |
| Bore above smallest UCP-series size | 78 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP318 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range. Brand-specific OEM equivalents pending multi-source data. |
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 UCP318 model number is decoded
UCP318 belongs to NTN's UCP line of cast-iron pillow blocks built to JIS B 1559 housing boundary dimensions around a JIS B 1558 UC318D1 insert. NTN's numbering ties the unit to its components: UCP318 means the P318 housing carrying the UC318D1 insert, with the last two digits denoting the 90 mm bore in the 3-series duty class. The foundation drawing needs four numbers: H 118 mm centre height, L 430 mm total length, J 330 mm between the 33 mm bolt holes, and a 90 mm shaft passing through the 190 mm OD insert. The 3-series section is the heavy-duty end of the range: a UC3 high-capacity insert in the longest, strongest housing, specified for shock loads and long conveyor centres. The upright base carries the shaft parallel to and above the mounting surface, which is the arrangement fan, conveyor and transmission drives use whenever a plinth or rail is available. Large-bore mounted units like this are selected on calculated bearing life plus foundation quality — the cast base is now a structural part of the drive, not just a convenient clamp. Food and packaging lines choose this unit when the layout allows an external mount: it lives outside the washdown zone, sealed and greased for life intervals that outlast a production campaign. Use grade 8.8 foundation bolts with flat washers under both head and nut, and pull them in stages in a cross pattern; the cast feet are strong in compression but a single over-torqued bolt can crack an ear. Basic ratings of the UC318D1 insert are 158 kN dynamic and 107 kN static; the assembled UCP318 weighs about 22.0 kg.
Typical equipment & failure modes
Common applications
- cement and clinker handling
- sugar-mill and fertiliser plant drives
- heavy bulk-handling conveyors
- vibrating feeder and screen-adjacent positions where setscrew retorque is routine
Known failure patterns
- over-greasing that churns the charge, overheats the bearing and blows the seal lip
- cracked cast ear from mounting on an uneven face and pulling one bolt fully first
- housing-foot cracking beside an over-torqued or under-supported foundation bolt
Selection pitfalls — read before you substitute
- UCP318 is located on the shaft by setscrews only; for shock reversing drives consider an adapter-lock insert family instead, since setscrew points indent the 90 mm journal over time.
- UCP318 at 90 mm uses M27 bolts that need a torque wrench and a cross pattern; pulling one bolt first tips the 118 mm centre height and binds the insert.
- The 3-series insert makes UCP318 the highest-rated unit at 90 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP318 needs a prepared horizontal surface at the 118 mm centre height: shim both feet with full-width packs so the 430 mm base seats over its full area.
Frequently asked questions
How is UCP318 locked to the shaft, and how tight should the setscrews be?
The UC318D1 insert uses two collar setscrews on the 90 mm shaft. Tighten them to NTN's torque table for this bore size in sequence — half torque on the first, full on the second, then back to the first — and re-torque after the first 24–48 running hours once the collar has seated.
When should I choose a pillow block like UCP318 instead of a flanged unit?
Choose the UCP318 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 118 mm above the 430 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
What are the dimensions of an UCP318 mounted bearing?
UCP318 takes a 90 mm shaft (insert UC318D1, 190 mm OD) and has a unit mass of about 22.0 kg. Housing figures: centre height H 118 mm, length L 430 mm, bolt centres J 330 mm, foot holes 33 mm for M27 bolts.
What does the UCP318 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; P the upright pillow block housing; 3 is the duty series; the last digits encode the 90 mm bore. UCP318 is built from housing P318 plus insert UC318D1 (D1 = greasable).
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.