21308 Spherical Roller Bearing Dimensions
The ENRO 21308 is a spherical roller bearing in the 21300 series, 40 × 90 × 23 mm. Boundary dimensions follow the ISO 15 dimension series.
Three checks for the 21308
Most wrong replacements come from one of these. Each answer below comes from the ENRO model table.
Does the size match?
Measure bore, outside diameter and width. The 21308 is 40 × 90 × 23 mm. If one value differs, see the adjacent sizes below.
Adjacent sizes →Which version do you need?
ENRO lists 2 versions: 21308W33, 21308K/W33. Match the seals, shields or bore type of the old bearing.
Versions table →Is the load rating enough?
Cr 104 kN, C0r 108 kN (catalog reference values). Check the life at your load and speed.
Life calculator →Not sure which one you have? Send any part number and we'll match the dimensionally equivalent ENRO model.
Check my 2130821308 dimensions and ratings
| Bore diameterd | 40 mm |
|---|---|
| Outside diameterD | 90 mm |
| WidthB | 23 mm |
| Chamfer dimension, min.r min | 1.5 mm |
| Basic dynamic load ratingCr | 104 kN |
| Basic static load ratingC0r | 108 kN |
| Limiting speed, greasen grease | 7,000 rpm |
| Limiting speed, oiln oil | 9,500 rpm |
| Weight (approx.)m | 0.75 kg |
| Series | 21300 |
| Material | GCr15 / GCr15SiMn chrome steel |
| Precision class | P0, P6 |
| Cage | Steel, brass |
| Origin | Made in China — Japanese-standard quality management |
Load ratings, limiting speeds and weights are catalog reference values. Values are confirmed per batch on request.
What “21308” means
- 213 — bearing type and dimension series code.
- 08 — bore code: code 08 × 5 = 40 mm.
21308 variants: 21308W33 / 21308K/W33
| Order as | Meaning |
|---|---|
| 21308W33 | Lubrication groove and holes. Groove and holes in the outer ring for relubrication. |
| 21308K/W33 | Tapered bore 1:12 + Lubrication groove and holes. Tapered bore, taper 1:12, for adapter or withdrawal sleeve mounting. Groove and holes in the outer ring for relubrication. |
Internal clearance (for example CN or C3) is stated on your RFQ. Suffix selector →
Print or save this table as PDF, or ask us to send the spec sheet with your quote.
Selection notes for the 21308
How this size sits against its neighbours in the 21300 series and the other spherical roller bearing series with the same bore. Every figure is from the ENRO model table.
- The 21308 is the fourth of sixteen sizes ENRO lists in the 21300 series, 40 × 90 × 23 mm.
- Next size down, the 21307, is 35 × 80 × 21 mm: five millimetres less bore, ten millimetres less outside diameter, two millimetres narrower.
- Next size up, the 21309, is 45 × 100 × 25 mm: five millimetres more bore, ten millimetres more outside diameter, two millimetres wider.
- Two other ENRO spherical roller bearings share the 40 mm bore: the 22208 (22200 series) is 80 × 23 mm, ten millimetres less outside diameter and the same width.
- The 21308 has a radial section of 25 mm ((D − d) / 2) on a 23 mm width, so its cross-section is taller than it is wide.
- Catalog reference values for the 21308: Cr 104 kN, C0r 108 kN, limiting speed 7,000 rpm with grease, 9,500 rpm with oil, weight 0.75 kg.
- Catalog dynamic load rating Cr is 104 kN for the 21308 against 65 kN for the 21307 (substantially less, 39 kN or 38%) and 125 kN for the 21309 (noticeably more, 21 kN or 20%).
- ENRO lists the 21308 in two versions: 21308W33, 21308K/W33. In the same series, the 21307 is listed in the same two versions; the 21309 is listed in the same two versions.
21308 bearing dimensions: range and series
16 sizes in the 21300 series.
Click a model to open its full specification page.
| Model | d mm | D mm | B mm | Cr kN | C0r kN | Grease rpm | Weight kg | Open model page |
|---|---|---|---|---|---|---|---|---|
| 21305 | 25 | 62 | 17 | On request | On request | On request | On request | |
| 21306 | 30 | 72 | 19 | 55 | 61 | 7,500 | 0.41 | |
| 21307 | 35 | 80 | 21 | 65 | 72 | 6,700 | 0.55 | |
| 21308 | 40 | 90 | 23 | 104 | 108 | 7,000 | 0.75 | This page |
| 21309 | 45 | 100 | 25 | 125 | 127 | 6,300 | 0.99 | |
| 21310 | 50 | 110 | 27 | 156 | 166 | 5,600 | 1.35 | |
| 21311 | 55 | 120 | 29 | 158 | 166 | 5,600 | 1.70 | |
| 21312 | 60 | 130 | 31 | 212 | 240 | 4,800 | 2.10 | |
| 21313 | 65 | 140 | 33 | 238 | 270 | 4,300 | 2.55 |
Catalog reference values. Full 21300 series table →
If the 21308 is not quite right
Nearest ENRO sizes by bore and by series. Check the housing and shaft before switching.
Other series with a 40 mm bore
Click a model to open its full specification page.
| Model | Series | d | D | B | Cr kN | Open model page |
|---|---|---|---|---|---|---|
| 21308 | 21300 | 40 | 90 | 23 | 104 | This page |
| 22208 | 22200 | 40 | 80 | 23 | 96 | |
| 22308 | 22300 | 40 | 90 | 33 | 150 |
Same 90 mm outside diameter, different bore
Click a model to open its full specification page.
Specifications and boundary dimensions
Built to be checked, not believed. Boundary dimensions follow the ISO 15 dimension series. Ratings follow ISO 281 and clearance groups ISO 5753-1; every value on a model page can be checked against the standard.
Boundary dimensions
Boundary dimensions follow the ISO 15 dimension series. Same base number, same d, D and B.
Tolerances
Defines the tolerance classes for radial bearings. State the class you need on the RFQ.
Internal clearance
Defines the clearance groups C2, CN, C3, C4 and C5. State the group you need on the RFQ.
Rating life
Basis of the L10 basic rating life. Use it with the catalog Cr in our life calculator.
Japan-managed quality control
ENRO is a bearing brand for distributors and MRO buyers. Our QC protocol follows Japanese industrial quality practice. Our bearings are made in China.
100% outgoing inspection
Every ENRO bearing — not a sample, every unit — passes outgoing inspection before shipment.
Same color, same box, same label
Every order ships in the same color box with the same label, so repeat shipments match on the shelf.
How to order the 21308: packing and marking
- Version
- Cylindrical or tapered bore (K, K30), with or without W33.
- Clearance group
- CN, C3 or another group. State it per line.
- Quantity per line
- Quantities per model and whether the order repeats.
- Marking options
- ENRO packing, OEM / private label or neutral packaging. State which one per line.
- Destination
- Port or country the order ships to.
Free samples are available.
Get a quote for a 21308
- Model or part number for each line
- Quantity per line
- Seal or shield, snap ring or bore type
- Clearance group, if not CN
- Destination port or country
We reply within 24 hours on business days.
Quote 21308Engineering tools built on our catalog data
21308 FAQ
What are the dimensions of the 21308 spherical roller bearing?
The 21308 has a bore (d) of 40 mm, an outside diameter (D) of 90 mm and a width (B) of 23 mm. Minimum chamfer r is 1.5 mm.
What load rating does the 21308 have?
Catalog reference values: basic dynamic load rating Cr 104 kN, static rating C0r 108 kN, limiting speed 7,000 rpm with grease. Values are confirmed per batch on request.
Which versions of the 21308 can I order?
ENRO lists the 21308 as 21308W33 (Lubrication groove and holes), 21308K/W33 (Tapered bore 1:12 + Lubrication groove and holes). State the clearance group you need in your RFQ.
Is the ENRO 21308 interchangeable with other brands' 21308?
Boundary dimensions follow the ISO 15 dimension series. The ENRO 21308 is dimensionally interchangeable with other brands' 21308 of the same size. Confirm seal, clearance and cage requirements in your RFQ.
Where are ENRO bearings made?
ENRO bearings are Made in China by partner factories, under Japan-managed quality control. Every unit passes 100% outgoing inspection before shipment.
Which bearings have the same bore as the 21308?
In the ENRO range, 22208 (40 × 80 × 23 mm), 22308 (40 × 90 × 33 mm) share the 40 mm bore. Outside diameter and width differ, so check the housing before switching.
Which clearance group should I order for the 21308?
CN (normal) suits most positions. C3 is common where the inner ring runs warmer than the outer ring, as in electric motors. Groups are defined in ISO 5753-1; state the one you need in your RFQ.
Quote the 21308
Send any part number and we'll match the dimensionally equivalent ENRO model. We reply within 24 hours on business days.