Exact model answerFafnir 203RR2: bore range and separate ring widths
Fafnir 203RR2 is a special radial ball-bearing reference. The 2017 drawing labels a 40 mm outside diameter, an 18.29 mm inner-ring width and a 12 mm outer-ring width. The two ring widths describe different parts of the cross-section; 12 mm is not the full inner-ring width.
The feature list describes a 5/8 in machined bore, while the drawing prints bore limits of 0.63500 to 0.64000 in and a 16.26 mm callout. Keep both pieces of evidence visible: 5/8 in equals 0.625 in and must not be substituted for the drawing bore. Do not derive a shaft fit from that short description.
The drawing shows contact seals protected by a steel shroud cap and an extended inner ring. The listed planter and windrower uses are examples of duty, not proof that this bearing fits a named machine, year or position.
- Catalogue marking
- Fafnir 203RR2
- Feature-list bore
- 5/8 in, machined bore (feature-list wording)
- Construction
- Round bore; extended inner ring; contact seals with a steel shroud cap
- Catalogue uses
- Planter coulter attachments and windrowers (catalogue examples, not machine-specific fitment)
Read each measurement separately
Bearing dimensions · published units retained| Measurement | Symbol | Metric | Inches |
|---|
| Bore diameter (drawing limits) | Not specified | 16.26 mm (drawing callout) | 0.63500–0.64000 in |
|---|
| Outside diameter (drawing limits) | Not specified | 40 mm (drawing callout) | 1.57435–1.57480 in |
|---|
| Inner-ring width (drawing limits) | Not specified | 18.29 mm (drawing callout) | 0.7153–0.7200 in |
|---|
| Outer-ring width (drawing limits) | Not specified | 12 mm (drawing callout) | 0.4677–0.4724 in |
|---|
What to check on your bearing
- Keep the complete bearing marking, including prefixes and suffixes.
- Measure the bore, outside diameter and both ring widths separately.
- Treat the catalogue example as historical evidence; confirm the current drawing and installation requirements before substitution.
The inch columns retain the two limits printed in the dated drawing, ordered lower to upper. Metric callouts are reproduced at the catalogue's precision and are not recalculated from those limits.
These excerpts do not provide a current certified drawing, fits, speed limits, load ratings, grease specification or a machine installation procedure. Do not infer a missing value from the base number or another variant.
203RR2, BB203RR2, 203RR3 and 203KRR2 must not be collapsed into a single designation. Likewise, P204RR6 and a marking carrying E8728 require separate checks.
Useful model distinctions
Factual reference: Timken Fafnir Farm Line Interchange, publication 5768 (01-17), printed page 8; catalogue snapshot 2026-10-03. Interpretation and checking notes by BearingScope.
Technical documents & data sheet
This product page is a BearingScope catalogue reference, not a manufacturer-certified drawing. Preserve the full brand and designation when comparing files.
- Record identity
- TIMKEN 203RR2
- Document matching
- Exact designation, assembly scope, revision and units must agree.
No verified redistributable CAD or manufacturer PDF is registered for this exact model. A catalogue image is not a dimensioned drawing. Missing technical files are not generated or replaced with unrelated models.
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