UCP305 bearing: complete specifications & equivalents
The UCP305 is a JIS B 1559 radial bearing sized 25 x 62 x 38 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 | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 38 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 23.5 kN |
| Basic static load rating C0 | 10.9 kN |
| Fatigue load limit Pu | 0.855 kN |
| Mass | 1400 g |
| Housing height H | 45 mm |
| Housing overall length L | 175 mm |
| Mounting bolt center distance J | 132 mm |
| Mounting hole diameter N | 17 mm |
| Manufacturer designation | UCP305 |
| 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 | 0.984 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 1.496 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 18.5 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) | 5 of 25 |
| Bore above smallest UCP-series size | 13 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP305 | 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 UCP305 model number is decoded
UCP305 is an NTN cast-iron pillow block — a setscrew-locking wide-inner-ring ball bearing (UC305D1) pre-assembled in a P305 two-bolt plummer housing. On the nameplate, UCP305 decodes as a UC wide-inner-ring insert in a P plummer block, 3-series duty, 25 mm bore; the UC305D1 designation shows the D1 greasable execution. Boundary data for the 25 mm bore: housing centre height 45 mm, base 175 mm, mounting centres 132 mm for M14 fasteners through 17 mm holes; the UC305D1 insert itself is 62 mm OD. 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. The 25–50 mm bore band is the workhorse of industry — belt conveyors, fans, agricultural drives and small process machines — which is why this range has the fullest choice of series and cover options. HVAC air-handling units carry fan shafts on this size, usually in warm roof-space air where the grease must be rated for continuous ambient temperature rather than load. On V-belt drives, align the pulleys before finally tightening the feet; the spherical seat lets you rotate the unit, but sliding the whole base on the foundation is what removes the belt-edge wear. Basic ratings of the UC305D1 insert are 23.5 kN dynamic and 10.9 kN static; the assembled UCP305 weighs about 1.4 kg.
Typical equipment & failure modes
Common applications
- belt conveyor head, tail and bend pulleys
- industrial fans and blowers
- agricultural augers and bucket elevators
- vibrating feeder and screen-adjacent positions where setscrew retorque is routine
Known failure patterns
- housing-foot cracking beside an over-torqued or under-supported foundation bolt
- grease starvation on long intervals in hot positions, with the ball set running on dried thickener
- fretting corrosion of the shaft journal under the wide inner ring after years of micro-creep
Selection pitfalls — read before you substitute
- The 3-series insert makes UCP305 the highest-rated unit at 25 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP305 needs a prepared horizontal surface at the 45 mm centre height: shim both feet with full-width packs so the 175 mm base seats over its full area.
- Self-aligning is not the same as free to move: the UC305D1 insert of UCP305 pivots to correct static misalignment, but a continuously bending shaft still frets the spherical seat.
- In this bore band the temptation is to choose UCP305 on shaft size alone; belt pull often dominates the radial load, so rate the unit against the overhung pulley force, not just transmitted power.
Frequently asked questions
What are the dimensions of an UCP305 mounted bearing?
UCP305 takes a 25 mm shaft (insert UC305D1, 62 mm OD) and has a unit mass of about 1.4 kg. Housing figures: centre height H 45 mm, length L 175 mm, bolt centres J 132 mm, foot holes 17 mm for M14 bolts.
What does the UCP305 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 25 mm bore. UCP305 is built from housing P305 plus insert UC305D1 (D1 = greasable).
How is UCP305 locked to the shaft, and how tight should the setscrews be?
The UC305D1 insert uses two collar setscrews on the 25 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 UCP305 instead of a flanged unit?
Choose the UCP305 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 45 mm above the 175 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
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.