6204 Bearing Dimensions, Load Ratings and Sourcing Guide

The 6204 bearing is a single-row deep groove ball bearing with 20 mm bore, 47 mm outer diameter and 14 mm width (20×47×14 mm). It is one of the most-used standard bearings worldwide — found in electric motors, water pumps, washing machines, agricultural equipment and automotive auxiliaries. This guide covers dimensions, load ratings, seal variants, clearance, common failures and what to verify before ordering.

What the numbers "6204" mean

The "6204" code follows the standard ISO/GB bearing designation system used by SKF, NSK, NTN, FAG, INA, Nachi, KOYO and Chinese manufacturers including NLHB.

For bore codes 00 / 01 / 02 / 03, multiply by 5 (10 / 12 / 15 / 17 mm). For bore codes 04 and above, the two-digit code × 5 = bore in mm. That is why 6204 → 20 mm, 6205 → 25 mm, 6206 → 30 mm.

Suffixes you will see on a 6204:

If your equipment nameplate just says "6204", it usually means open type with C3 clearance. Verify against your drawing before ordering.

Looking up other sizes? Try the Bearing Finder or the Cross-Reference Tool.

6204 dimensions, load ratings and weight

Boundary dimensions are fixed by ISO 15 (and GB/T 276). They do not vary between brands — a 6204 from SKF, NSK, NTN, FAG, INA and NLHB shares the same envelope.

Different brands publish C_r values with ±5% spread, depending on steel grade (GCr15 vs SUJ2 vs 52100), heat treatment and cage design. Do not compare C_r between brands directly — check which rating standard each catalogue declares (ISO 281 / GB/T 6391).

6204 vs adjacent models — when to step up or down

If your housing or shaft is already designed, you can often move to a neighbouring model. Here is how 6204 compares:

The 6204 is the most cost-effective point in this size class — high-volume production worldwide keeps pricing tight and stock wide. If you are designing from scratch and your load requires more than 14 kN C_r, step up to 6304 or 6205 rather than pushing 6204 to its limit.

Seal variants — ZZ vs 2RS vs open

This is the single most common mistake buyers make — ordering the wrong seal type. The three variants share the same boundary dimensions, so they fit the same housing, but they perform very differently.

Practical rule: if the original bearing in your equipment was a 2RS, always replace it with a 2RS. A ZZ in a wet environment will fail within weeks. The same goes the other way — an open bearing in a dusty environment will fail fast.

The seal lip colour carries meaning for some brands (SKF blue = low-friction, NSK red = standard contact) — but do not rely on colour alone. Verify by part number suffix.

Clearance — C3 vs C4 and why it matters

Internal radial clearance is how much the inner ring can move radially relative to the outer ring before the bearing rotates. The 6204 ships in several clearance classes:

Why C3 dominates electric motors: when the motor runs at rated temperature, the inner ring expands more than the outer ring (heat path + interference fit), reducing clearance. If you start at CN, the bearing ends up with too little clearance at operating temperature — it overheats and fails prematurely. Starting at C3 leaves room for that thermal expansion.

If you do not know what to specify: C3 is the safe default for motors and most rotating equipment. Use CN only if the application is low-temperature and low-interference-fit.

Applications — where the 6204 actually runs

The 6204 is not a niche bearing — it is one of the five most-used bearings in the world. Real-world applications:

In all these cases, 6204 is selected for one reason: the load/speed envelope is well within its ratings, the price is low because of global volume, and stock is everywhere. If your application pushes 6204 to its load limit, you have likely chosen the wrong bearing — move up to 6304 or 6205.

What NLHB verifies before quoting a 6204

A 6204 looks the same across every manufacturer — same d, D, B, same catalogue page, same photos. What differs is what happens inside the bearing and how the supplier verifies it.

Before quoting, NLHB confirms:

• Boundary dimensions — measured on caliper / micrometer, not just read off the catalogue
• Bore tolerance — verify the bearing matches your shaft tolerance class (k5, m5, etc.)
• Seal type — visually confirm ZZ / 2RS / open matches the order
• Clearance class — measured before and after mounting (clearance loss from interference fit is real)
• Brand and suffix — full part number recorded before quotation

On request, for production batches, NLHB can provide in-house measurement data on:

• Roundness of inner and outer raceway — measured on roundness tester
• Surface roughness R_a on raceway — measured on profilometer
• Vibration / noise grade Z1 / Z2 / Z3 / Z4 — measured on Anderonmeter per ISO 15242
• Radial clearance before mounting — per ISO 5753

If you are comparing suppliers, ask what they actually measure in-house. Most trading companies cannot answer. NLHB's answer is above — and the data comes with the shipment, not as marketing copy.

See the full Quality & Sourcing Process.

Cross-reference — SKF, NSK, NTN, FAG, INA equivalents

A 6204 from SKF, NSK, NTN, FAG, INA, Nachi, KOYO and NLHB shares the same boundary dimensions. The part number is the same — the suffix system varies.

NLHB declares these as compatible references for sizing only — not authorized equivalents. The listed brands are trademarks of their respective owners. For OEM spec-in applications, always confirm against the equipment drawing.

Full lookup: Cross-Reference Tool.

Common failures and what to check first

When a 6204 fails in service, one of these is usually the cause:

80% of premature bearing failures are not bearing defects. They are installation, lubrication, contamination, or application errors. If a 6204 fails in less than its rated L10 life, look at the application first — not the supplier.

If you have a failed 6204 and need help diagnosing, send us a photo of the raceway and the application details. We can usually tell within a working day what failed and why.

FAQ

What does 6204 mean on a bearing?

6204 is the ISO/GB designation: 6 = deep groove ball bearing type, 2 = dimension series, 04 = bore code (× 5 = 20 mm bore). All brands (SKF, NSK, NTN, FAG, INA, NLHB) use the same code for the same bearing.

What is the difference between 6204 ZZ and 6204 2RS?

6204 ZZ has two metal shields — protects against larger debris but not moisture. 6204 2RS has two rubber contact seals — seals in grease and keeps out water. ZZ has lower drag and higher speed; 2RS is better for wet or dusty environments.

What is C3 clearance?

C3 means radial internal clearance greater than standard (for 6204: 11 – 21 µm). C3 is the default for electric motors because thermal expansion at operating temperature takes up some clearance — if you start at standard (CN), the running clearance ends up too tight.

Can I replace a 6204-2RS with a 6204 ZZ?

Not recommended in wet or dusty environments. A ZZ shield is not a seal — moisture and fine dust will pass. In a dry, clean environment (e.g. an indoor fan motor), the swap may work, but expect shorter life. Always match the original seal type.

How long does a 6204 last?

Under proper load, speed, lubrication and alignment, the L10 rated life of a 6204 in a typical motor application is 15,000 – 30,000 operating hours. Real life depends on application. If yours fails in under 5,000 hours, the problem is almost never the bearing — it is the application.

How do I know what 6204 variant I have?

Look at the seal area: nothing visible → open type; metal shield visible → ZZ; rubber lip visible → 2RS. Then read the part number stamped on the side of the inner ring or on the seal. If the marking is gone, measure bore / outer / width — if 20×47×14, it is a 6204.

What is the difference between 6204 and 62/22?

6204 has 20 mm bore. 62/22 has 22 mm bore. Both are 62-series but the bore code 04 (standard, × 5 = 20) vs /22 (explicit mm, 22). They are not interchangeable — the shaft size is different.

Can NLHB supply 6204 in small quantities?

Yes. NLHB handles both replacement batches (50 – 500 pcs) and production volumes. For replacement, we typically quote against your part number and quantity; for production, we ask for the application and annual demand so we can suggest the right variant and clearance.

Sourcing checklist — what to send NLHB

If you want a quote on 6204 bearings, send us:

• Part number — e.g. 6204-2RS C3 (not just "6204")
• Brand reference — if you are replacing SKF / NSK / NTN, tell us the brand so we can confirm the suffix mapping
• Quantity — replacement batch or production volume
• Application — motor, pump, appliance, agricultural machine, etc.
• Operating conditions — speed, temperature, environment (wet/dusty/clean)
• Precision class — if you need P6 or P5 instead of standard P0
• Clearance — C3 unless you know otherwise
• Special requirements — food-grade grease, high-temperature grease, non-standard cage, etc.

Send this to [email protected] or use the Request a Quote page. We confirm the spec, verify supply and quote a realistic lead time — not a placeholder.

Related resources

• 6200 Bearing Dimensions, Load Basics and Replacement Guide
• 608ZZ vs 608-2RS: Which Seal Fits Your Application?
• What to Prepare Before Requesting a Custom Bearing Quote
• 6204 product page — full dimensions, interchange table, inquiry entry
• Bearing Finder — search by bore / OD / width
• Cross-Reference Tool — match SKF / NSK / NTN / FAG / INA to NLHB
• Quality & Sourcing Process — what we verify before quoting