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R3 bearing dimensions & suffix variants

Look up recorded dimensions for designations beginning with R3. The table retains complete manufacturer designations so special suffixes and different dimensional variants remain visible.

On this page7 sections

Find by measured dimensions

Enter bore d, outside diameter D and width B. Use decimals or inch fractions such as 1/2 or 1 1/4.

For tapered assemblies use total width T; for units or flanged bearings also check the mounting drawing.

Catalogue variant evidence

R3 — published size and closure variants

R3 is the base grouping for the specific records below. Read the complete designation and publisher on each row. The source unit is retained beside the converted unit. A shield or seal can change the width; equal bore and outside diameter do not establish the same envelope.

3 source-labelled records; 3 shown initially.

Publisher / full modelClosure / materiald×D×B in mmd×D×B in inchesSource unit
SMBR3OpenChrome steel4.7625×12.7×3.96748 mm0.1875×0.5×0.1562 ininch
SMBR3ZZShieldedChrome steel4.7625×12.7×4.9784 mm0.1875×0.5×0.196 ininch
SMBR3-2RSSealedChrome steel4.7625×12.7×4.9784 mm0.1875×0.5×0.196 ininch
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Keep RS, 2RS, ZZ and width suffixes distinct

The table records the publisher’s open, shielded or sealed column. An unlisted “RS” marking is not rewritten as “2RS”. Keep special endings such as W21, W23 or a fractional bore suffix: they can identify a different width or bore. No automatic cross-brand substitution is approved.

Metric values converted from printed inch decimals inherit the source rounding. For example, 0.2812 in converts to 7.14248 mm; that extra decimal detail is arithmetic, not a tolerance or a machining target. Never silently round an inch bearing into the nearest metric size. Missing speed, clearance, precision, internal ball diameter, material grade or exact lubricant remain unknown.

Publisher references: SMB product charts and Enduro 1600-series data; checked 2026-10-02. Original BearingScope interpretation. No stock, sales, vehicle fitment or redistributable CAD is implied. Material names describe the source page, not a certificate for every item sold under a similar number.

Source-labelled catalogue reference

R3 — PEER catalogue dimensions

Independent technical reference from PEER’s historical 2009 sheets; checked 2026-10-03. These are catalogue records, not current-stock claims or replacement approvals. Printed units are kept separate.

PEER nominal envelope — d is bore, D is outside diameter, B is width
Full catalogue modeld×D×B (mm)d×D×B (in)Closed width / execution scope
PEER · R seriesR34.7625×12.7×3.96748 mmConverted from the printed inch open row.1875×.5000×.1562 in.1960 in / 4.9784 mmSealed/shielded B column; not an invented suffix-specific order code

Read ratings without transferring them to another execution

Cr and Cor are catalogue basic load ratings, not allowable application loads. Oil/grease values below are explicitly for open bearings where supplied. They are not sealed-bearing or machine operating-speed approvals. A dash means withheld or not established here.

Published PEER ratings — N and r/min
ModelDynamic Cr / static CorOpen: oil / greaseEvidence boundary
R31312 / 492 N—R-series speeds omitted: open-execution applicability not expressly identified in this table.

Printed decimal conversions inherit catalogue rounding; more decimal places do not create manufacturing accuracy. Special bores must not be rounded to a nearby metric bearing. The historical table does not establish an exact RS/2RS, NR, ABEC, C3, ceramic, vehicle or kit execution unless explicitly listed. No CAD or interchange approval is implied.

Exact model evidence

R3 dimensions and recorded technical data

The recorded R3 base designation measures 4.762×12.7×3.967 mm (inside diameter d × outside diameter D × width B). This answer uses unsuffixed records from NSK, EZO. It does not assign the same dimensions or operating ratings to every suffix.

The numeric series boundary is preserved: a longer number is not included merely because its first digits match. 4 recorded variants are listed. A dash means the value is missing, not zero.

Brand / full designationNamed dimensions (mm / in)Dynamic C (kN)Static C0 (kN)Reference speed (rpm)Limiting speed (rpm)Mass (kg / g)
NSKR3Deep groove ball bearing
Bore diameter (d)
4.762 mm
0.18748 in
Outside diameter (D)
12.7 mm
0.5 in
Bearing width (open) (B)
3.967 mm
0.156181 in
1.43 kN0.485 kN——0.00221 kg2.21 g
EZOR3Deep groove ball bearing
Bore diameter (d)
4.762 mm
0.18748 in
Outer diameter (D)
12.7 mm
0.5 in
Inner ring width (B)
3.967 mm
0.156181 in
1.3 kN0.485 kN——0.00214 kg2.14 g
NSKR3ZZDeep groove ball bearing
Bore diameter (d)
4.762 mm
0.18748 in
Outside diameter (D)
12.7 mm
0.5 in
Catalogue width (symbol unverified)
4.978 mm
0.195984 in
1.43 kN0.485 kN——0.00279 kg2.79 g
EZOR3 2RSDeep groove ball bearing
Bore diameter (d)
4.762 mm
0.18748 in
Outer diameter (D)
12.7 mm
0.5 in
Inner ring width (B)
4.978 mm
0.195984 in
1.3 kN0.485 kN——0.00271 kg2.71 g
Compare recorded seals, clearance, precision and materials

Manufacturer wording is retained. A missing property is not inferred from another brand or a similar suffix.

Brand / designationClosureOriginal precisionClearanceCageMaterialLubricant
NSK R3OpenNot recordedNot recordedNot recordedNot recordedNot recorded
EZO R3Open (no closure suffix in this catalogue marking)Not recordedNot recordedNot recordedHigh-carbon chromium bearing steelNot recorded
NSK R3ZZMetal shields on both sides (ZZ)Not recordedNot recordedNot recordedNot recordedNot recorded
EZO R3 2RSTwo contact rubber sealsNot recordedNot recordedNot recordedHigh-carbon chromium bearing steelNot recorded

How to compare these values

  • Use the displayed dimension names and original symbols. Housing length L, height H2 and flange width are not bearing outside diameter D. A catalogue width with an unverified symbol must not be assumed to be inner-ring width B or assembly width T. Open the product record for mounting dimensions and geometry.
  • Inch values are calculated from the recorded millimetres using 25.4 mm per inch, rounded to six decimal places. They do not change a metric bearing into an inch-series bearing. Gram values are converted from the recorded mass in kilograms.
  • C and C0 describe different rating conditions. They are not a single safe working-load limit and cannot replace an application load calculation.
  • Reference and limiting speeds are separate catalogue values. The source grease/oil context is shown where recorded. Lubricant, seals, loads, fit, clearance and cooling affect the usable operating speed.
  • A common base number does not prove equivalent seals, clearance, precision, material or interchangeability. Open the full designation for these fields.

Related prefix matches — other model numbers may appear

These discovery results can contain a longer number or a different component. They are not specifications for the requested exact model. Open the complete product to inspect its original geometry.

Check the drawing before substituting

Nominal dimensions are not shaft-fit tolerances. Different variants can add grooves, flanges, wider rings or assembly components. When the table has different dimensions, the complete designation—not the shared prefix—controls.

Reference basis & data limits

Manufacturer terminology is retained in the product records. Technical reference basis: JTEKT Basic Bearing Knowledge (boundary dimensions, tolerance classes and lubrication); NSK Bearing ABCs (lubrication, designations and clearance); NTN technical FAQs (closure codes and component interchange); SKF rolling-bearing selection and maintenance references.

Selection workflows and catalogue grouping are BearingScope editorial aids. Verify the current drawing and application requirements before using a candidate. Missing database information is not converted into an assumed match.

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