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6203 Deep Groove Ball Bearing 17x40x12mm
The 6203 bearing bridges the gap between the 6202 bearing (15mm bore) and the 6204 bearing (20mm bore) with a 17mm shaft diameter. At 40mm OD and 12mm width, it provides 9.58 kN dynamic load capacity — 25 percent more than the 6202 bearing while requiring only 5mm more housing diameter. GCr15 bearing steel rings and balls, ABEC-1 or ABEC-3 precision, and three sealing configurations make it a standard choice for electric motors from 1.5 kW to 3 kW.
Key Specifications
Sealing: Open, ZZ metal-shielded, or 2RS double rubber-sealed configurations. ZZ shields maintain the full 18,000 RPM rating without friction penalty. 2RS nitrile seals for wet, dusty, or outdoor environments.
Speed and Load: 18,000 RPM in open and ZZ configurations; 12,000 RPM in 2RS sealed. 9.58 kN dynamic load (Cr) and 4.78 kN static load (Cor) at standard CN clearance.
Material and Precision: Rings and balls in GCr15 bearing steel (AISI 52100 equivalent), through-hardened to HRC 60–64. Standard precision ABEC-1 and ABEC-3. 100% dimensional inspection per batch.
Operating Direction: Single-row deep groove geometry handles combined radial and bidirectional axial loads. Axial capacity approximately 25 percent of radial dynamic rating.
Temperature Range: Standard polyurea grease rated -20°C to 120°C continuous. High-temperature synthetic greases to 150°C available for OEM orders.
For any inquiries, please contact with our Supporting Team at sales@yuanhecd.com.
| Model | 6203 |
| Type | Open / ZZ Shielded / 2RS Sealed |
| Bore (d) | 17 mm |
| OD (D) | 40 mm |
| Width (B) | 12 mm |
| Dynamic Load Cr | 9.58 kN |
| Static Load Cor | 4.78 kN |
| Max Speed | 18,000 RPM (Open/ZZ) / 12,000 RPM (2RS) |
| ABEC | ABEC-1 / ABEC-3 |
6203 bearing bridges the 6202 bearing (15mm bore) and 6204 bearing with a 17mm shaft. At 40mm OD and 12mm width, 9.58 kN dynamic load — 25 percent more than the 6202 bearing in only 5mm more housing diameter. A standard deep groove ball bearing for electric motors from 1.5 kW to 3 kW.
Bore x OD x Width
17 x 40 x 12 mm
Dynamic Load Cr
9.58 kN
Static Load Cor
4.78 kN
Max Speed
18,000 RPM
Sealing
Open / ZZ / 2RS
Precision
ABEC-1 / ABEC-3
Shielding and Lubrication
The 6203 bearing ships in three configurations matched to operating environment. Open bearings accept oil bath, oil-mist, or circulating-oil lubrication at the full 18,000 RPM speed rating. ZZ metal shields use non-contact SPCC steel covers pressed into the outer ring, forming a narrow labyrinth that blocks coarse workshop debris and fiber dust. Because the ZZ shield never touches the inner ring, it adds zero friction — speed stays at 18,000 RPM.
2RS rubber seals employ nitrile (NBR) contact lips riding on the inner ring shoulder. The lip blocks water spray, cement dust, agricultural soil, and chemical mist. The tradeoff is a speed reduction to 12,000 RPM due to seal lip friction and the resulting temperature rise of 8\u00b0C to 12\u00b0C at rated speed. For applications where the operating environment includes rain, washdown, or abrasive dust at speeds under 8,000 RPM, the 2RS seal prevents lubricant washout and contaminant entry without needing an external seal in the housing.
The 12mm width of the 6203 bearing \u2014 1mm more than the 6202 bearing \u2014 accommodates a deeper seal groove profile and approximately 8 percent larger grease reservoir in sealed variants. This extra volume extends relubrication intervals in continuous-duty electric motors. Factory fill is polyurea-thickened mineral grease at 25 to 30 percent of free internal volume. For food-processing washdown environments, 440C stainless steel rings and FKM seals are available against drawing review.
Performance
The 6203 bearing delivers 9.58 kN dynamic load and 4.78 kN static load. Within the 6200-series deep groove ball bearing family, it occupies the middle ground: the 6202 bearing (15x35x11mm) carries 7.65 kN, and the 6204 bearing (20x47x14mm) carries 12.8 kN. Stepping from the 6202 bearing to the 6203 bearing gains 25 percent more dynamic capacity with 2mm additional bore and 5mm additional OD — a favorable tradeoff when shaft diameter must increase from 15mm to 17mm for structural reasons.
Against the 6003 bearing — which shares the 17mm bore — the 6203 bearing gains 5mm OD (40mm vs 35mm) and 2mm width (12mm vs 10mm). The payoff is 59 percent more dynamic load capacity (9.58 vs 6.0 kN). In a 1.1 kW industrial fan at 1,450 RPM with 1.8 kN radial load, upgrading the housing from 35mm to 40mm to fit the 6203 bearing instead of the 6003 bearing extends calculated L10 life from approximately 12,000 hours to 42,000 hours — and eliminates the need for a mid-life bearing replacement in the equipment service plan.
Compared to the 6204 bearing (20x47x14mm, 12.8 kN), the 6203 bearing saves 7mm OD, 2mm width, and 41g of weight (65g vs 106g) while retaining 75 percent of the load capacity. When the shaft is 17mm and cannot be stepped up to 20mm, or when the housing diameter is limited to 40mm, the 6203 bearing is the correct selection. The 6203 bearing also shares the 12mm width with the 6201 bearing (12x32x10mm) but carries 40 percent more load (9.58 vs 6.82 kN) for shafts in the 12mm to 17mm range.
OEM and Customization
Yuanhe supplies the 6203 bearing with full customization for volume orders. Standard internal clearance is CN. C3 clearance is specified for electric motor applications where the inner ring operates 10\u00b0C to 20\u00b0C hotter than the outer ring during continuous duty — this thermal gradient reduces running clearance, and C3 prevents preload-induced torque rise and life reduction. C2 clearance suits precision measurement spindles and low-speed positioning tables. C4 clearance is available for heavy interference fits on both shaft and housing.
Grease options range from standard polyurea (general purpose, -20\u00b0C to 120\u00b0C) to low-noise polyurea for electric motor applications (tested below 35 dB(A)), fluorinated high-temperature grease (intermittent to 150\u00b0C), and NSF H1 food-grade grease for incidental food contact. Stainless steel 440C rings and balls are available for water pump, marine, and washdown service; note that 440C dynamic load rating is approximately 7.7 kN. Cage materials: glass-fiber-reinforced PA66 (standard), machined brass for continuous duty above 120\u00b0C, and pressed steel for compact envelope constraints. Custom bore tolerances, snap-ring grooves on the outer ring, and double-sealed or double-shielded configurations ship against drawing review. Standard lead time is 7 to 15 days with batch dimensional reports. Submit your specification or drawing for a quote.
Applications
Electric motors from 1.5 kW to 3 kW (IEC frame sizes 80-90), automotive alternators and coolant pumps, domestic washing machine drum and motor bearings, industrial fan and blower shaft bearings, light conveyor head and tail pulleys with up to 40mm shaft, HVAC condenser and cooling tower fan motors, small centrifugal and peripheral pump impeller shafts, power tool armature and spindle bearings, fitness equipment flywheel and pedal crank assemblies, office equipment imaging drum and fuser roller bearings, and agricultural implement disc and idler bearings. Any application requiring a 17mm shaft within a 40mm housing bore.
Frequently Asked Questions
What is the difference between the 6203 bearing and the 6003 bearing? +
Both fit a 17mm shaft. The 6203 bearing measures 40mm OD x 12mm width with 9.58 kN dynamic load. The 6003 bearing measures 35mm OD x 10mm width with 6.0 kN dynamic load — 59 percent less capacity. The 6203 bearing requires 5mm more housing diameter and 2mm more width. Choose the 6203 bearing when load or fatigue life determines the design. Choose the 6003 bearing when the housing bore cannot exceed 35mm.
Can a 6203 bearing replace a 6204 bearing? +
Only with shaft and housing modification. The 6203 bearing has a 17mm bore and 40mm OD. The 6204 bearing requires a 20mm bore and 47mm OD and carries 33 percent more dynamic load (12.8 vs 9.58 kN). If the shaft can be stepped down from 20mm to 17mm and the housing reduced from 47mm to 40mm, the 6203 bearing fits a more compact envelope — but the load capacity reduction must be verified against the application duty cycle.
When should I specify C3 radial clearance for a 6203 bearing? +
C3 clearance is standard for electric motor applications where the inner ring runs 10\u00b0C to 20\u00b0C hotter than the outer ring during continuous duty. Without C3, the thermal gradient preloads the bearing, increasing torque and accelerating fatigue. C3 is also specified for interference-fit inner rings where the press fit alone consumes 0.005mm to 0.012mm of radial clearance. CN (normal) clearance is sufficient for light press fits and applications where both rings operate at similar temperatures.
What is the continuous-duty speed limit for a 6203 2RS bearing? +
The 6203 2RS bearing is rated to 12,000 RPM. At this speed, seal lip temperature rise is 8\u00b0C to 12\u00b0C above ambient, and the polyurea grease maintains stability to 120\u00b0C. For applications running above 8,000 RPM continuously, ZZ shields with external labyrinth sealing are recommended — this eliminates seal friction and restores the 18,000 RPM open-bearing speed envelope. At 3,600 RPM and below (4-pole motor speed), 2RS seal wear rates are negligible and the bearing is rated for its full calculated L10 life.
