Single Row Deep Groove Ball Bearings With Filling Slots
TFL supplies single row deep groove ball bearings with filling slots for applications requiring higher radial load capacity than standard single row deep groove ball bearings of similar size. The product list covers 92 metric configurations in 200 and 300 series, with bore sizes from 25 mm to 85 mm. Buyers can compare open, shielded, and selected sealed options, CN, C3, or C4 clearance, chrome steel or nylon cages, P0 / ABEC 1 tolerance, load ratings, lubrication, and maximum speed. These bearings are commonly used in gearboxes, conveyors, agricultural equipment, material handling systems, pumps, fans, and general machinery where radial load capacity is the main selection factor. TFL can help source standard or customized filling slot bearing options based on bearing number, drawing, sample, or application requirements.
Increase in Load Capacity with Filling Slots
Key Application Scenarios
Various Materials and Sealing Options
Filling Slot Ball Bearing Selection Guide
This page provides high-quality, high-capacity alternatives for single-row deep groove ball bearings with filling slots (often referred to as “Max-Capacity” bearings). By utilizing a loading notch to insert a larger ball complement, these bearings significantly increase dynamic radial load ratings compared to standard Conrad-type deep groove bearings of equivalent dimensions. When selecting a replacement model, it is vital to analyze radial/axial load ratios, operating speeds, running clearances, cage metallurgy, and closure requirements (open, shielded, or sealed).
What Is a Filling Slot (Max-Capacity) Ball Bearing?
Unlike standard deep groove ball bearings that use the Conrad method (eccentric ring displacement to load balls), a filling slot bearing features matching notches ground into the inner and outer ring raceways. These filling slots allow the insertion of a much higher count of larger-diameter balls, yielding a substantial increase in radial load capacity within a very compact envelope.
The major engineering trade-off is that filling slot bearings are highly sensitive to axial (thrust) loads. The loading notch interrupts the raceway shoulder, meaning any significant thrust force can cause the balls to ride over the edge of the slot, leading to rapid failure. Sourcing the correct alternative requires a careful evaluation of load vectors, speeds, lubricant viscosity, and your specific mounting arrangement.
Product Range and Model Options
Our catalog features 92 metric configurations, predominantly focusing on the heavy-duty 200 and 300 series maximum-capacity bearings. With bore diameters ranging from 25 mm to 85 mm, these alternatives are manufactured with high-grade chrome steel rings and balls, open or shielded designs, C3/C4 radial internal clearances, and engineered polyamide (nylon) or pressed steel cages.
| Selection Item | Options in This Product List | What to Confirm for Your Application |
|---|---|---|
| Series range | 200 and 300 series (Max-Capacity equivalents) | Match the boundary dimensions and compare radial dynamic load ratings against standard bearings |
| Bore range | 25 mm to 85 mm | Verify shaft and housing tolerances, along with available installation space |
| Closure type | Open, shielded (Z/2Z), and selected sealed (RS1/2RS) | Evaluate ambient dust, washdown conditions, grease retention, friction, and thermal speed limits |
| Clearance | CN (Normal), C3, and selected C4 models | Check the interference fit, operating temperature rise, and required running clearance |
| Cage material | Engineered Polyamide (TN9) or pressed steel | Assess operating temperatures (e.g., polyamide limits), vibration levels, and synthetic lubricants |
| Load direction | Strictly predominant radial load | Examine any potential bi-directional or momentary axial thrust forces due to the filling slot design |
When Should You Choose a Filling Slot Bearing?
Choosing a filling slot equivalent is highly recommended when your machinery operates under heavy, continuous radial loads but is restricted by a tight, compact housing envelope. This design is widely used in heavy-duty industrial machinery where a standard Conrad deep groove bearing of the same size would suffer from premature fatigue due to radial overloading.
Conversely, a filling slot bearing is the wrong choice if your application experiences high axial forces, dynamic thrust reversals, or extremely high rotational speeds. In these scenarios, please share your equipment drawings and operating parameters with our engineers to verify if a standard Conrad deep groove bearing or a different bearing type is a safer, more reliable replacement.
Available Filling Slot Bearing Models
Representative equivalent configurations include 305, 305-2Z, 306/C3, 307-2RS1, 308 TN9/C3, 309-2Z, 310/C3, 312-2Z, 314, and 217-2Z. This selection covers open designs for direct oil bath lubrication, shielded models for basic exclusion of debris, and rubber-sealed options for excellent grease retention.
Nomenclature suffixes are critical: TN9 indicates a glass-fiber reinforced polyamide 66 cage (ideal for quiet running and low weight, but temperature-limited to around 120°C), while 2Z and 2RS1 indicate shields and seals respectively. Retaining the complete designation during cross-reference checks is vital to ensuring a safe replacement.
Typical Applications
Due to their high radial capacity, these maximum-capacity alternatives are extensively used in heavy-duty gearboxes, industrial conveyors, agricultural machinery, bulk material handling systems, centrifugal pumps, textile machinery, reducers, and general rotating equipment where radial loads dominate over axial thrust.
In harsh, dusty, or high-moisture environments (such as mining or agricultural applications), we highly recommend upgrading to shielded or sealed variations to protect the loading slot and internal raceways from ingress.
Engineering Warning: Avoid High Axial Loads on Max-Capacity Bearings
Do not select a replacement bearing based on physical dimensions alone. Under moderate to high axial loading, the ball path in a filling slot bearing will intersect the loading notch. This causes localized stress concentrations, severe ball-to-edge friction, and rapid subsurface spalling. Never replace a standard Conrad deep groove ball bearing with a filling slot bearing if the application involves high, dynamic, or continuous thrust loads.
Need a Filling Slot Ball Bearing?
Send us your complete bearing number, boundary dimensions, estimated load conditions, operating speeds, clearance requirements, cage material preference, and quantity. Our technical team will review and quote the most suitable filling slot bearing alternatives for your machinery.
Request a Filling Slot Bearing QuoteHow to Choose from the Product List
Start by identifying your existing part number or measuring the bore, outside diameter, and width. Next, compare the dynamic radial load ratings, maximum limiting speeds, closure preferences, radial clearance (such as C3 for electric motors or hot gearboxes), and cage metallurgy. If your original OEM bearing features specialized suffixes like TN9, C3, or 2Z, please include the full designation in your inquiry. For critical engineering projects, also share the equipment type, operating speeds, estimated radial/axial load values, shaft/housing fits, lubrication method, and photos of the worn sample to help our technical team confirm suitability.Why Source Filling Slot Bearings from TFL?
TFL / SDTFL Bearing is a trusted independent bearing supplier and your strategic sourcing partner. Once you confirm the specifications, drawings, or sample details, we coordinate with vetted, high-precision manufacturing resources to source the exact equivalent products required for your operations. Our rigorous pre-shipment quality control process verifies dimensional tolerances, radial clearance margins, cage integrity, and packaging quality. Custom clearance specifications, specialized high-temperature grease fills, private label marking, and neutral packaging can be customized based on your order volumes and project needs. You can also browse our complete deep groove ball bearing range for related bearing options.TFL / SDTFL Bearing is an independent bearing supplier and sourcing partner. Brand-style bearing numbers and suffixes are used strictly for replacement, alternative, cross-reference, or interchange identification. Filling slot bearings must be selected based on comprehensive technical parameters, with special emphasis on radial and axial load limits, speed, clearance, and lubrication conditions.
FREQUENTLY ASKED QUESTIONS
What is the biggest difference from ordinary deep groove ball bearings?
Will the filling slots make installation easier?
Does this bearing require frequent maintenance or lubrication?
Do you offer samples? What is the Minimum Order Quantity (MOQ)?
Sample availability and Minimum Order Quantity (MOQ) can vary by product model. Please check the specific product page or contact our sales team for details on the bearing you need.