30203 Bearing Dimensions
30203 tapered roller bearing: 17 mm bore, 40 mm OD, 13.25 mm total width (FULI catalog). Designation breakdown and size-equivalent codes. Quote.
30203 specifications
| Bore d | 17 mm |
|---|---|
| Outside diameter D | 40 mm |
| Total width T | 13.25 mm — assembled width of cup and cone |
| Seal / shield options | Open (cup and cone, no seals) |
| Material | GCr15 chrome bearing steel (rings and rolling elements) |
| Precision | P0 (standard); P6 on request |
| Radial clearance | Set during mounting (adjustable, not a C-class value) |
Load ratings & speed
| Dynamic load rating Cr | 20.70 kN |
|---|---|
| Static load rating C0r | 21.90 kN |
| Weight | 0.079 kg — approx. |
Values from FULI's catalog; confirm for your application.
Nearby 30200/30300 series sizes: 30310 bearing · 30202 bearing · 30213 bearing · 30214 bearing
Grease quantity for 30203: bearing grease fill calculator.
Buying 30203 in quantity? See bearing wholesale supplier for pricing by quantity and shipping, and bearing manufacturer in China for how to check the factory.
How to read the 30203 designation
| Segment | Meaning |
|---|---|
| 3 | Single row tapered roller bearing (metric, ISO 355) |
| 02 | Dimension series 02 |
| 03 | Bore code 03 → 17 mm bore. ISO bore code (00–03 = 10/12/15/17 mm; 04 and above = code × 5 mm). |
30203 interchange
30203 is an ISO designation: bore d, outside diameter D and total width T are the same at each maker. The letters each maker adds are series, design or cage codes, not seal codes, so the full number is different at every brand. Send us the full number on your old bearing and we confirm the match.
Brand names are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by these companies. Part numbers are shown for interchange reference only. FULI dimensions, load ratings and speeds come from the FULI catalog.
Tolerances and fits for 30203
FULI makes 30203 to P0 as standard, with P6 on request. P0 is the Normal tolerance class of ISO 492; P6 limits are tighter. These are the P0 limits for the 17 × 40 × 13.25 mm size.
| Dimension | Nominal, mm | Deviation, µm | Limits, mm |
|---|---|---|---|
| Bore d (Δdmp) | 17 | 0 / −12 | 17.000 / 16.988 |
| Outside diameter D (ΔDmp) | 40 | 0 / −14 | 40.000 / 39.986 |
| Total width T (ΔTs) | 13.25 | +200 / 0 | 13.450 / 13.250 |
Δdmp and ΔDmp: deviation of the mean bore and mean outside diameter in one radial plane. ΔTs: assembled width of cone and cup, from the ISO 492 table for metric tapered roller bearings. Cone width B and cup width C: 0 / −120 µm each.
Shaft and housing fits (general guidance)
For an inner ring that turns with a solid steel shaft under normal load, bearing makers’ fit tables give 17 k5 for the shaft of 30203. The cup usually sits in an H7 or J7 housing bore so that it can be moved when the pair is adjusted.
| Seat | Deviation, µm | Limits, mm | Fit with 30203 |
|---|---|---|---|
| Shaft 17 k5 | +9 / +1 | 17.009 / 17.001 | 1 to 21 µm interference |
| Housing 40 H7 | +25 / 0 | 40.025 / 40.000 | 0 to 39 µm clearance |
| Housing 40 J7 | +14 / −11 | 40.014 / 39.989 | 11 µm interference to 28 µm clearance |
Taking the loosest and the tightest combination of limits, a P0 30203 on a 17 mm k5 shaft has 1 to 21 µm interference. Its cup has 0 to 39 µm clearance in an H7 bore and 11 µm interference to 28 µm clearance in a J7 bore.
This is general guidance, not a FULI specification. Heavy or shock loads, a hollow shaft, a thin-walled, split or light-alloy housing, or a large temperature difference between shaft and housing call for other classes, and the drawing of your machine takes priority.
If the outer ring turns and the shaft stands still, as in an idler pulley or a wheel hub, the fits are reversed: the housing gets the interference fit (for example N7 or P7) and the shaft a sliding one (g6 or h6).
Sources: ISO 492 tables as printed in the NTN catalogue CAT. No. 2203/E (Tables 6.4 and 6.5) and the RKB tolerance catalogue; ISO 286-2 for the seats; SKF and NTN fit tables for the shaft and housing classes.
30203 compared with nearby sizes
30203 measures 17 × 40 × 13.25 mm: bore d, outside diameter D and total width T. Other tapered roller bearings on this site for the same 17 mm shaft are 30303 (17 × 47 × 15.25 mm).
30303 is the next heavier choice for a 17 mm shaft, with an outside diameter 7 mm larger (47 mm) and 2 mm more width (15.25 mm). In FULI's catalog 30303 has a dynamic load rating of 28.30 kN against 20.70 kN and a weight of about 0.129 kg against 0.079 kg for 30203.
In the 302 series the sizes either side of 30203 are 30202 for a 15 mm shaft and 30204 for a 20 mm shaft.
| Model | Compared with this page | d × D × T (mm) | Cr (kN) | Weight (kg) |
|---|---|---|---|---|
| 30203 | This page | 17 × 40 × 13.25 | 20.70 | 0.079 |
| 30202 | Next size down | 15 × 35 × 11.75 | 15 | 0.053 |
| 30204 | Next size up | 20 × 47 × 15.25 | 28.20 | 0.126 |
| 30303 | Same bore | 17 × 47 × 15.25 | 28.30 | 0.129 |
Cr and weight from FULI's catalog; — = not listed on this site.
30203 weight, load ratings and speed
FULI's catalog gives the weight of 30203 as about 0.079 kg, so 100 bearings weigh about 7.9 kg and 1,000 about 79 kg before packing. The weight is for the cone and cup together.
30203 has a dynamic load rating Cr of 20.70 kN and a static load rating C0r of 21.90 kN. Cr is the load used to work out rating life; C0r is the reference for loads carried while the bearing is stationary or turning slowly.
Values from FULI's catalog; confirm for your application.
30203 cone and cup
30203 is supplied as a complete bearing: the cone (inner ring with rollers and cage) and the cup (outer ring). The total width T of 13.25 mm applies when the two are assembled; the cone and the cup on their own are each narrower. Tell us if you need only the cone or only the cup.
Tapered roller bearings carry radial load and axial load in one direction, so 30203 is normally mounted as one of a pair facing each other, and the end play or preload is set when the pair is adjusted on the shaft. That is why FULI lists the clearance as set during mounting, not as a C-class value.
30203 dimensions in inches
The nearest common inch shaft size to the 17 mm bore of 30203 is 11/16 in (17.46 mm), 0.46 mm larger than the bore, so 30203 will not go on it. Inch shafts need an inch bearing, not a metric one with a sleeve or shim.
| Dimension | Millimetres | Inches |
|---|---|---|
| Bore d | 17 mm | 0.6693 in |
| Outside diameter D | 40 mm | 1.5748 in |
| Total width T | 13.25 mm | 0.5217 in |
Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.
Grease for 30203
FULI supplies tapered roller bearings rust-protected and normally without grease; grease is added when 30203 is mounted. Relubricating 30203 from the side takes about 2.65 g each time by the formula in our grease calculator: 0.005 × D × T = 0.005 × 40 × 13.25.
How FULI supplies 30203
The standard 30203 from FULI has GCr15 chrome steel rings and rollers and P0 precision, with P6 on request. Where an order states a requirement for the total width T (13.25 mm for 30203) or the cone height, each set is checked on a height gauge.
Rings are marked with a brand you are authorised to use, with the FULI brand, or left neutral, as your order states. The box is printed with the model, precision class and brand.
Inquiries that leave out the prefix or suffix letters are the usual cause of a wrong quote, so write the full designation, for example 30203.
Tools and guides for 30203
- Bearing size finder: look up a size from bore, OD and width
- Bearing weight chart
- Bearing grease fill calculator
- Shaft and housing tolerance chart
- Tapered roller bearing number lookup
- Bearing lubrication basics
- Ball bearing vs roller bearing
- How to choose wheel hub bearings
- All bearing products and model pages
Typical applications
- Vehicle wheel hubs and axles
- Gearboxes and reducers
- Agricultural machinery
- Conveyor pulleys
FAQ
What is the difference between 30203 and 30303?
Both fit a 17 mm shaft. 30203 is 17 × 40 × 13.25 mm and 30303 is 17 × 47 × 15.25 mm, so 30303 has an outside diameter 7 mm larger (47 mm) and 2 mm more width (15.25 mm). In FULI's catalog 30303 has a dynamic load rating of 28.30 kN against 20.70 kN and a weight of about 0.129 kg against 0.079 kg for 30203. Choose 30303 for a higher load where the housing has room for it; 30203 keeps the housing smaller.
What size is 30203 in inches?
30203 is 0.6693 × 1.5748 × 0.5217 in (17 × 40 × 13.25 mm, d × D × T). The nearest common inch shaft size to the 17 mm bore of 30203 is 11/16 in (17.46 mm), 0.46 mm larger than the bore, so 30203 will not go on it. Use an inch bearing on an inch shaft.
How much does 30203 weigh?
About 0.079 kg in FULI's catalog, so 100 pieces weigh about 7.9 kg before packing. The weight is for the cone and cup together.
How much grease does 30203 need?
About 2.65 g each time it is relubricated from the side (0.005 × 40 × 13.25). FULI ships 30203 rust-protected without grease, so the first fill is made at mounting.
Is 30203 the same size across brands?
Bore d, outside diameter D and total width T are the same: 30203 is an ISO designation. The letters each maker adds (NSK HR and J, NTN 4T-, Koyo JR, FAG XL, SKF J2/Q) are series, design or cage codes, not seal codes.