FlowMarket
Where to source bearings: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the bearing — designation or bore, outside diameter and width, load direction and magnitude, speed, internal clearance, sealing, lubrication and precision class — and the AI agent matches you with verified bearing manufacturers and distributors, then requests prices, stock and lead times from every match at once. Getting matched is free for buyers.
Sourcing bearings
Bearings are dimensionally standardised under ISO 15, so a 6205 has the same 25 mm bore, 52 mm outside diameter and 15 mm width whoever makes it. That standardisation is what makes the market competitive and cross-referencing straightforward — and also what makes it easy to buy the wrong thing, because the suffixes after the base number carry most of the engineering.
Two bearings with the same designation can differ in internal clearance, cage material, sealing, grease fill and precision class. Those differences decide whether the bearing runs for years or seizes in a fortnight.
Bearing types
Ball bearings
Deep groove ball bearings are the default: they carry radial load with a useful axial component, run fast, cost little and come sealed for life. Angular contact types take heavier axial load in one direction and are mounted in pairs for spindles and screw drives. Self-aligning ball bearings tolerate shaft misalignment where housings cannot be machined in line.
Roller bearings
A line contact instead of a point contact means far higher load capacity. Cylindrical roller bearings carry heavy radial load and allow axial movement; tapered rollers take combined radial and axial load and are adjusted in opposed pairs, as on a vehicle hub; spherical rollers accept both heavy load and misalignment, which is why they dominate in fans, crushers and conveyor pulleys. Needle bearings do the same in a minimal radial section.
Plain bearings and specials
- Bronze and sintered bushings — simple, quiet, tolerant of shock and edge loads; often oil impregnated.
- Polymer and PTFE-lined — maintenance free and dry running, good for food and washdown.
- Thrust bearings — pure axial load, ball or roller.
- Linear bearings and guides — recirculating ball bushings and profile rail guides for linear axes.
What to specify when sourcing
These details decide both the part number and the price:
- Designation or dimensions — the full code including suffixes, or bore, outside diameter and width.
- Load — radial, axial or combined, with magnitude and whether it is steady or shock.
- Speed — operating rpm, and whether it runs continuously or intermittently.
- Internal clearance — CN standard, C3 or C4; critical for interference fits and hot running.
- Sealing — open, shielded (ZZ/2Z) or contact sealed (2RS), and the contamination present.
- Lubrication — grease fill and type, oil, or relubrication interval and food-grade requirement.
- Temperature — operating and peak; above about 120 °C both cage and grease change.
- Precision class — P0 normal, or P6/P5/P4 for spindles and measuring equipment.
- Cage material — steel, brass or polyamide, which limits speed and temperature.
- Brand & quantity — whether an equivalent brand is acceptable, and annual volume.
Clearance and fit — where the suffix earns its keep
Internal clearance is the play inside the bearing before it is fitted, and it does not survive installation. Pressing a bearing onto a shaft with an interference fit expands the inner ring and consumes part of that clearance; running hot does the same, because the inner ring heats faster than the outer. Specify CN standard clearance where a C3 was needed and the bearing can end up preloaded to zero clearance in service, which sends the temperature up and the life down sharply. This is why C3 is routine on electric motors, and why replacing a bearing by base number alone — dropping the suffix, since it looks like a variant code — is one of the most expensive small mistakes in maintenance purchasing. Quote the full designation including suffixes, or describe the fit and operating temperature and let the supplier confirm the clearance.