UCFLX08 bearing: complete specifications & equivalents
The UCFLX08 is a JIS B 1559 radial bearing sized 40 x 90 x 49.2 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 | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 49.2 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 36 kN |
| Basic static load rating C0 | 20.4 kN |
| Fatigue load limit Pu | 1.6 kN |
| Mass | 2000 g |
| Housing height H | 179 mm |
| Housing overall length L | 111 mm |
| Mounting bolt center distance J | 148 mm |
| Mounting hole diameter N | 16 mm |
| Manufacturer designation | UCFLX08 |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 1.937 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 25 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) | 8 of 25 |
| Bore above smallest UCFL-series size | 28 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCFLX08 | 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 UCFLX08 model number is decoded
UCFLX08 is an NTN two-bolt rhombus flanged unit — a setscrew-locking UCX08D1 ball bearing insert pre-assembled in a FLX08 cast-iron flange housing. Reading the designation: UC marks the wide-inner-ring, setscrew-locking insert; FL marks the two-bolt rhombus flange housing; the X code identifies the duty series and the final two digits encode the 40 mm bore. Key mounting figures: flange height H = 179 mm, overall length L = 111 mm across the diamond, bolt centres J = 148 mm, and each ear takes a 16 mm (M14) fastener for the 40 mm shaft. 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. Mining feeder and screen-feeder drives use the heaviest available section at this bore: the base must resist belt-pull reaction, and crews grout the sole rather than bolting to bare plate. For the flanged form, the mounting face must be flat within the housing’s own tolerance; a weld bead or plate step under one ear twists the housing and binds the insert even though the shaft looks centred. Basic ratings of the UCX08D1 insert are 36 kN dynamic and 20.4 kN static; the assembled UCFLX08 weighs about 2.0 kg.
Typical equipment & failure modes
Common applications
- belt conveyor head, tail and bend pulleys
- industrial fans and blowers
- agricultural augers and bucket elevators
- wet, abrasive or chemically aggressive environments relying on the lip seals and slingers
Known failure patterns
- spherical-seat fretting that welds insert to housing and destroys the self-aligning action
- water-emulsified grease after washdown with the fitting facing upward
- setscrew loosening and inner-ring fretting on a shaft that was never re-torqued after run-in
Selection pitfalls — read before you substitute
- The X insert of UCFLX08 is wider and rated above the 2-series part at 40 mm, but it is not interchangeable with a 3-series unit in a damaged application — check the housing length and bolt centres before swapping.
- As a rhombus flange, UCFLX08 pulls against the frame through only two M14 bolts on 148 mm centres; the mounting plate must be stiff enough not to bend between them under belt load.
- When ordering covers for UCFLX08, note the steel and cast-iron cover executions change the unit mass and envelope but not the 148 mm mounting centres.
- With a 40 mm shaft the M14 foundation bolts of UCFLX08 must be re-checked after run-in — paint crush under the feet is enough to loosen both the feet and the setscrews.
Frequently asked questions
What are the dimensions of an UCFLX08 mounted bearing?
UCFLX08 takes a 40 mm shaft (insert UCX08D1, 90 mm OD) and has a unit mass of about 2.0 kg. Flange figures: height H 179 mm, length L 111 mm, bolt centres J 148 mm, holes 16 mm for M14 bolts.
What does the UCFLX08 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 40 mm bore. UCFLX08 is built from housing FLX08 plus insert UCX08D1 (D1 = greasable).
How is UCFLX08 locked to the shaft, and how tight should the setscrews be?
The UCX08D1 insert uses two collar setscrews on the 40 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 UCFLX08 instead of a pillow block?
Choose the UCFLX08 two-bolt flange when the 40 mm shaft meets a vertical frame or side plate: the diamond housing bolts flush with two M14 bolts on 148 mm centres. A UCP pillow block is used when the shaft runs above a horizontal mounting surface.
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.