UCP326 bearing: complete specifications & equivalents
The UCP326 is a JIS B 1559 radial bearing sized 130 x 280 x 135 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 | 130 mm |
| Outer diameter D | 280 mm |
| Width B | 135 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 254 kN |
| Basic static load rating C0 | 214 kN |
| Fatigue load limit Pu | 11.7 kN |
| Mass | 69000 g |
| Housing height H | 180 mm |
| Housing overall length L | 600 mm |
| Mounting bolt center distance J | 480 mm |
| Mounting hole diameter N | 40 mm |
| Manufacturer designation | UCP326 |
| 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 | 5.118 in |
|---|---|
| Outer diameter D | 11.024 in |
| Width B | 5.315 in |
| ISO bore code | 26 |
| Radial section height (D−d)/2 | 75 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) | 24 of 25 |
| Bore above smallest UCP-series size | 118 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP326 | 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 UCP326 model number is decoded
NTN ships the UCP326 as a matched assembly — UC326D1 insert swaged into the P326 cast-iron pillow block — so the fitter never has to set bearing-to-housing clearance. The code breaks down as insert family UC, housing form P (pillow block), duty series 3, bore code ending in the 130 mm shaft size; the unit is built from insert UC326D1 and housing P326. For layout work on UCP326: the 130 mm shaft centre sits 180 mm above the sole (H), the footprint is 600 mm long (L), bolt centres are 480 mm (J), and the foot holes suit M33 (40 mm) bolts. 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. Above 90 mm bore these are primary process drives — mining conveyors, bulk materials handling, heavy fans — where the 3-series insert and massive casting protect against shock and contamination. Sugar and fertiliser handling relies on this unit where corrosion and fine crystals attack everything: the sealed insert and the grease nipple let crews purge contaminated grease after each campaign. Check the shaft itself is straight to roughly 0.05 mm over the bearing centres before blaming a noisy new unit: mounted bearings accept housing misalignment but cannot offset a bent shaft. Basic ratings of the UC326D1 insert are 254 kN dynamic and 214 kN static; the assembled UCP326 weighs about 69.0 kg.
Typical equipment & failure modes
Common applications
- large induced-draft fans
- quarry and aggregate screens
- ship-loader and stacker drives
- low-speed heavily loaded pulleys where the static rating governs the selection
Known failure patterns
- 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
- lip-seal failure from grit past the slinger, followed by grease loss and abrasive wear
Selection pitfalls — read before you substitute
- The 3-series insert makes UCP326 the highest-rated unit at 130 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP326 needs a prepared horizontal surface at the 180 mm centre height: shim both feet with full-width packs so the 600 mm base seats over its full area.
- At replacement time, measure the 130 mm shaft journal — a worn or deeply indented journal under the setscrews will let a brand-new UCP326 creep identically to the old one.
- UCP326 is located on the shaft by setscrews only; for shock reversing drives consider an adapter-lock insert family instead, since setscrew points indent the 130 mm journal over time.
- At 130 mm bore, rigging and alignment dominate the UCP326 installation: the cast unit is lifted into place on the shaft, aligned on the spherical seat, and only then foot-bolted.
Frequently asked questions
What are the dimensions of an UCP326 mounted bearing?
UCP326 takes a 130 mm shaft (insert UC326D1, 280 mm OD) and has a unit mass of about 69.0 kg. Housing figures: centre height H 180 mm, length L 600 mm, bolt centres J 480 mm, foot holes 40 mm for M33 bolts.
What does the UCP326 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 130 mm bore. UCP326 is built from housing P326 plus insert UC326D1 (D1 = greasable).
How is UCP326 locked to the shaft, and how tight should the setscrews be?
The UC326D1 insert uses two collar setscrews on the 130 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 UCP326 instead of a flanged unit?
Choose the UCP326 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 180 mm above the 600 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
How often should I relubricate an UCP326 unit?
There is no single interval for UCP326: the UC326D1 insert is regreased through the D1 fitting while the shaft turns, using an NLGI 2 lithium or lithium-complex grease. Quarterly is typical for normal ambient conveyor duty; shorten to weekly or monthly where temperatures exceed about 70 °C, water is present, or dust is heavy.
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.