UCFLX05 bearing: complete specifications & equivalents
The UCFLX05 is a JIS B 1559 radial bearing sized 25 x 62 x 38.1 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 | 38.1 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 21.6 kN |
| Basic static load rating C0 | 11.3 kN |
| Fatigue load limit Pu | 0.795 kN |
| Mass | 1000 g |
| Housing height H | 141 mm |
| Housing overall length L | 83 mm |
| Mounting bolt center distance J | 117 mm |
| Mounting hole diameter N | 12 mm |
| Manufacturer designation | UCFLX05 |
| 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 & UCFL-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 1.5 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 18.5 mm |
| Smallest bore in UCFL-series | 12 mm |
| Largest outer diameter in UCFL-series | 300 mm |
| Width range across UCFL-series | 31–145 mm |
| Bore position in UCFL-series (smallest first) | 5 of 25 |
| Bore above smallest UCFL-series size | 13 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCFLX05 | 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 UCFLX05 model number is decoded
NTN delivers UCFLX05 as a matched unit — the UCX05D1 insert is locked into the FLX05 rhombus cast-iron flange at the factory and arrives greased and sealed. NTN's numbering ties the unit to its components: UCFLX05 means the FLX05 housing carrying the UCX05D1 insert, with the last two digits denoting the 25 mm bore in the X-series duty class. The mounting detail needs four numbers: H 141 mm flange height, L 83 mm across the ears, J 117 mm between the 12 mm holes, and a 25 mm shaft through the 62 mm OD UCX05D1 insert. The X section is NTN’s intermediate-duty build: a wider UCX insert with a higher rating sits in a longer, sturdier housing than the 2-series unit at the same bore. The diamond flange carries the shaft square to a vertical face — a welded frame, side plate or gearbox wall — so no base plinth and no shim pack under the bearing are required. Most general industrial shafting in the 25–50 mm range ends up on exactly this class of unit: designers trade the 2, X and 3 sections against conveyor centres and belt tension rather than against absolute capacity. Small marine and dockside conveyors use this unit with stainless fasteners through the feet; the cast iron tolerates salt atmosphere far better than pressed-steel housings once paint is chipped. In wet or washdown positions, orient the grease fitting at 45° and purge after every wash; water trapped between the slinger and lip seal emulsifies the grease even when the unit is sealed. Basic ratings of the UCX05D1 insert are 21.6 kN dynamic and 11.3 kN static; the assembled UCFLX05 weighs about 1.0 kg.
Typical equipment & failure modes
Common applications
- small crushers and screening feeds
- textile line-shafting
- machine-tool chip conveyors
- elevated-temperature positions where grease life, not bearing rating, sets the interval
Known failure patterns
- lip-seal failure from grit past the slinger, followed by grease loss and abrasive wear
- spherical-seat fretting that welds insert to housing and destroys the self-aligning action
- water-emulsified grease after washdown with the fitting facing upward
Selection pitfalls — read before you substitute
- As a rhombus flange, UCFLX05 pulls against the frame through only two M10 bolts on 117 mm centres; the mounting plate must be stiff enough not to bend between them under belt load.
- Do not confuse UCFLX05 with a bare UCX05D1 bearing: replacing only the insert is possible, but the housing FLX05 must be unworn and the spherical seat cleaned and coated with anti-seize.
- When ordering covers for UCFLX05, note the steel and cast-iron cover executions change the unit mass and envelope but not the 117 mm mounting centres.
- With a 25 mm shaft the M10 foundation bolts of UCFLX05 must be re-checked after run-in — paint crush under the feet is enough to loosen both the feet and the setscrews.
- The X insert of UCFLX05 is wider and rated above the 2-series part at 25 mm, but it is not interchangeable with a 3-series unit in a damaged application — check the housing length and bolt centres before swapping.
Frequently asked questions
What does the UCFLX05 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; FL the two-bolt rhombus flange housing; X is the duty series; the last digits encode the 25 mm bore. UCFLX05 is built from housing FLX05 plus insert UCX05D1 (D1 = greasable).
How is UCFLX05 locked to the shaft, and how tight should the setscrews be?
The UCX05D1 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 rhombus flange unit like UCFLX05 instead of a pillow block?
Choose the UCFLX05 two-bolt flange when the 25 mm shaft meets a vertical frame or side plate: the diamond housing bolts flush with two M10 bolts on 117 mm centres. A UCP pillow block is used when the shaft runs above a horizontal mounting surface.
Is the UCFLX05 bearing self-aligning?
Yes within limits. The UCX05D1 insert has a spherical outer diameter that pivots in the FLX05 housing bore, compensating for a few degrees of static misalignment between shaft and foundation. It does not compensate for a bent shaft or dynamic deflection while running.
What are the dimensions of an UCFLX05 mounted bearing?
UCFLX05 takes a 25 mm shaft (insert UCX05D1, 62 mm OD) and has a unit mass of about 1.0 kg. Flange figures: height H 141 mm, length L 83 mm, bolt centres J 117 mm, holes 12 mm for M10 bolts.
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.