Fit and operating clearance
Review shaft and housing tolerances, ring temperatures and the locating arrangement. C3 identifies a clearance group; it is not a precision grade or a universal upgrade for every motor.
MAINLAND BEARING · INDUSTRIAL SUPPLY
Electric motor bearings specified for your operating conditions.
For motor OEMs, repair businesses and industrial distributors, the bearing designation is only the start of a repeatable specification. Mainland supplies common 6000 and 6200 series deep groove ball bearings, with closure, clearance, lubrication and inspection requirements reviewed before quotation. Share the motor duty and both bearing positions so the offered configuration can be checked against your equipment.
APPLICATION REVIEW01 02 03
Resolve these points before ordering.
Closure and lubrication
Specify open, shielded or sealed construction together with the lubrication method. Confirm grease type, fill and temperature range for the approved bearing. A suffix alone is not enough to establish a speed limit.
Noise and electrical duty
If running noise or vibration is an acceptance criterion, agree the test method and limits. For inverter-driven motors, identify any electrical-current protection requirement separately; an ordinary steel bearing is not an insulated bearing.
MODEL & DIMENSION COMPARISON
Catalog starting points for your review.
These are reference models, not approved selections for a specific machine. Final suitability, suffix and performance data require technical confirmation.
| Model | Bearing type | Bore d (mm) | Outside D (mm) | Width B/T (mm) | Details |
|---|---|---|---|---|---|
| 6203 | Deep Groove Ball Bearing | 17 | 40 | 12 | View specifications → |
| 6204 | Deep Groove Ball Bearing | 20 | 47 | 14 | View specifications → |
| 6205 | Deep Groove Ball Bearing | 25 | 52 | 15 | View specifications → |
| 6206 | Deep Groove Ball Bearing | 30 | 62 | 16 | View specifications → |
PROCUREMENT QUESTIONS
Before you choose a replacement.
Does every electric motor require C3 clearance?
No. Select clearance against the equipment specification and the expected clearance after mounting and at operating temperature. Use the original approved requirement when replacing a bearing.
Can 6204 be replaced by 6205?
Not as a dimensional replacement. Our catalog lists 6204 at 20 × 47 × 14 mm and 6205 at 25 × 52 × 15 mm. Compare the complete arrangement, not just the bearing series.
Further technical reading: NSK guide to fits and internal clearance. Third-party guidance explains selection principles; it does not establish Mainland product ratings or endorsements.