Home/
Blog/
Bearing Size Chart Guide: Ball, Roller & Thrust Bearing Dimensions

8 min read

Bearing Size Chart Guide: Ball, Roller & Thrust Bearing Dimensions

Picture of Robert Robert : May 25, 2026 3:16:21 AM

Bearing Selection Bearing Dimensions
Bearing Size Chart Guide: Ball, Roller & Thrust Bearing Dimensions
Bearing Size Chart Guide: Ball, Roller & Thrust Bearing Dimensions
16:56

What Is a Bearing Size Chart?

A bearing size chart is a standardized reference table that maps bearing part numbers to their three core physical dimensions — bore diameter (d), outer diameter (D), and width (B or T) — along with load ratings and speed limits.

Charts are issued by major manufacturers including SKF, NSK, NTN, FAG, and Timken, and aligned to ISO dimensional standards. Two bearings carrying the same ISO part number from different brands will have identical outer dimensions. They will physically fit the same shaft and housing.

Why Dimensions Are the Starting Point

Every bearing selection — replacement or new design — starts with three numbers: bore (d), outer diameter (D), and width (B or T). Get all three right and the bearing fits. Miss one and you are placing another order.

Beyond fit, dimensions matter for three reasons:

Load Capacity

Larger cross-sections handle heavier loads. A 6308 (40 mm bore) has a dynamic load rating of 40.5 kN. A 6204 (20 mm bore) is rated at 12.8 kN — roughly a third of that, despite half the bore diameter.
Speed Limits

Speed limits fall as bore increases. A 6200 (10 mm bore) runs to 22,000 rpm on grease. A 6210 (50 mm bore) is limited to 7,000 rpm. Bigger bearings need more conservative speed margins.
Cross-Brand Sourcing

Part number matching alone is not enough. Always verify d, D, and B when switching suppliers.

How to Read a Bearing Size Chart

Bearing size charts follow ISO dimensional conventions, defined under ISO 492 for radial bearings and ISO 355 for tapered roller bearings. Every chart uses the same column structure:

Column What It Tells You
Bearing No. Encodes type, series, and bore — see decoder below
d (mm) Bore — must match your shaft diameter
D (mm) Outer diameter — must match your housing bore
B or T (mm) Width (radial bearings) or height (thrust bearings)
C (kN) Dynamic load rating — for rotating load applications
C₀ (kN) Static load rating — for stationary or slow oscillating loads
Max RPM Limiting speed under grease lubrication
⚡ Bore Code Shortcut

For 6200 and 6300-series bearings, multiply the last two digits by 5 to get the bore in mm. Bearing 6208 → 08 × 5 = 40 mm bore. Codes 00–03 are fixed exceptions (10, 12, 15, 17 mm).

For a detailed walkthrough of the reading process, see our How to Read a Bearing Size Chart guide.

Free Tool

Bearing Size Finder

Enter bore, OD, and width to find matching bearing numbers instantly. Cross-reference across 25,000+ bearing types.

Open Cross Reference Tool →

Ball Bearing Size Chart

Deep groove ball bearings handle radial loads as their primary function, with the ability to carry moderate axial loads in both directions. That combination of versatility and low cost makes them the default choice across electric motors, water pumps, gearboxes, agricultural equipment, and home appliances.

The 6200 series (ISO dimension series 02) covers light-to-moderate radial loads. The 6300 series (ISO dimension series 03) shares the same bore sizes but a larger outer diameter — more ball complement, higher load ratings, and a housing that needs to be bored wider.

A 6205 bearing has a 25 mm bore, 52 mm outer diameter, 15 mm width, dynamic load rating of 14.8 kN. Its 6300-series equivalent, the 6305, shares the 25 mm bore but increases OD to 62 mm and raises the dynamic load rating to 22.5 kN — a 52% improvement in load capacity for the same shaft size.

6200 Series — ISO Dimension Series 02

Bearing No. d (mm) D (mm) B (mm) C (kN) C₀ (kN) Max RPM
6200 10 30 9 5.10 2.36 22,000
6201 12 32 10 6.82 3.10 20,000
6202 15 35 11 7.65 3.72 18,000
6203 17 40 12 9.56 4.75 17,000
6204 20 47 14 12.80 6.55 15,000
6205 25 52 15 14.80 7.80 13,000
6206 30 62 16 19.50 11.20 11,000
6207 35 72 17 25.70 15.30 9,500
6208 40 80 18 29.10 17.80 8,500
6209 45 85 19 32.50 21.20 7,800
6210 50 90 20 35.10 23.20 7,000

Source: SKF Rolling Bearings Catalogue. Verify against the current manufacturer datasheet for engineering calculations.

6300 Series — ISO Dimension Series 03

Bearing No. d (mm) D (mm) B (mm) C (kN) C₀ (kN) Max RPM
6300 10 35 11 8.06 3.72 20,000
6301 12 37 12 9.72 4.55 19,000
6302 15 42 13 11.40 5.40 17,000
6303 17 47 14 13.50 6.55 16,000
6304 20 52 15 15.90 7.80 14,000
6305 25 62 17 22.50 11.40 12,000
6306 30 72 19 28.00 15.00 10,000
6307 35 80 21 33.50 19.20 8,800
6308 40 90 23 40.50 24.00 7,800
6309 45 100 25 52.70 32.00 7,000
6310 50 110 27 62.00 38.00 6,400

Source: SKF Rolling Bearings Catalogue.

6200 vs 6300 — when to step up: If a 6205 keeps failing under load on a fixed 25 mm shaft, the 6305 is the next step. Same bore. Load rating up 52%. Your housing needs re-boring from 52 mm to 62 mm. That is the only trade-off.

Browse our deep groove ball bearings or go directly to the 6205 product page to check availability and request a quote.

Roller Bearing Size Chart

Cylindrical roller bearings carry significantly heavier radial loads than ball bearings of the same bore. The roller-to-raceway contact is a line rather than a point, which spreads load across a larger area. A NU206 (30 mm bore) is rated at 36 kN dynamic, versus 19.5 kN for the 6206 ball bearing — 85% more load capacity on the same bore.

The tradeoff is axial capacity. Most NU-series bearings carry zero axial load. If your application has combined radial and axial loading — helical gears, for example — you need angular contact or spherical roller bearings. See our cylindrical roller bearing guide for application selection detail.

NU200 Series — Cylindrical Roller Bearings

Bearing No. d (mm) D (mm) B (mm) C (kN) C₀ (kN) Max RPM
NU204 20 47 14 25.50 17.00 12,000
NU205 25 52 15 27.00 18.30 11,000
NU206 30 62 16 36.00 25.00 9,500
NU207 35 72 17 48.00 34.00 8,000
NU208 40 80 18 56.00 40.00 7,000
NU209 45 85 19 60.00 44.00 6,300
NU210 50 90 20 64.00 49.00 6,000
NU211 55 100 21 83.00 63.00 5,300
NU212 60 110 22 96.00 75.00 5,000

Source: SKF Rolling Bearings Catalogue. Verify current datasheet before use in load calculations.

Thrust Bearing Size Chart

Thrust bearings handle axial loads — forces running parallel to the shaft. They appear in vertical pump shafts, machine tool spindles, automotive steering columns, and jacking mechanisms.

⚠ Common Misapplication

Single-direction thrust ball bearings (51100 series) cannot carry radial load. This is the most common misapplication we see. If your shaft has combined loading, angular contact ball bearings handle both directions in a single unit.

51100 Series — Single Direction Thrust Ball Bearings

Bearing No. d (mm) D (mm) T (mm) C (kN) C₀ (kN)
51100 10 24 9 7.65 17.00
51101 12 26 9 8.00 18.00
51102 15 28 9 8.00 18.30
51104 20 35 10 15.10 29.00
51105 25 42 11 18.00 36.00
51106 30 47 11 18.30 38.00
51107 35 52 12 20.40 42.50
51108 40 60 13 27.00 58.50
51110 50 70 14 29.00 67.00
51112 60 85 17 42.50 100.00

Source: SKF Rolling Bearings Catalogue (51100 series). Verify against current datasheet before use.

For thrust bearings, C₀ is the primary sizing parameter. The C column is listed for completeness, but the static rating governs axial load selection in this series. For background, see our static vs dynamic load ratings guide.

Metric vs. Inch Bearing Sizes

Metric bearings cover global industrial and OEM applications. Inch bearings remain common in North American agricultural machinery and equipment built before metric standardization.

Feature Metric Bearings Inch Bearings
Standards body ISO / DIN ABMA / AFBMA
Bore Millimeters Fractions of an inch
Common series 6200, 6300, NU, 51100 R series, 1600 series
Primary markets Global North America, legacy UK
Example 6205 — 25 mm bore R10 — 5/8" (15.875 mm) bore

When switching between systems, match all three dimensions. A 0.5 mm OD mismatch is enough to cause the outer ring to spin under load. Use our Bearing Cross Reference tool to cross-reference part numbers across brands or measurement systems.

Bearing Number Decoder

This decoder applies to 6×00-series deep groove ball bearings. NU-series, 22-series, and 32-series bearings follow variant prefix conventions.

Position Meaning Example: 6207-2RS/C3
First digit Bearing type 6 = deep groove ball bearing
Second digit ISO dimension series 2 = series 02 (6200 family)
Last two digits Bore code × 5 = bore mm 07 × 5 = 35 mm
Suffix before slash Sealing type 2RS = double rubber lip seal
Suffix after slash Internal clearance C3 = greater than standard

Type codes:

6 Deep groove ball bearing
7 Angular contact ball bearing
NU / NJ / N Cylindrical roller bearing
22 / 23 Spherical roller bearing
32 / 33 Tapered roller bearing
51 / 52 Thrust ball bearing

Real-World Sourcing Notes

Three errors come up repeatedly when customers contact us after a failed replacement:

Ordering by part number without measuring the old bearing

Stamped numbers corrode and get misread. A "6205" misread as "6206" on a dirty shaft means a wrong order and downtime. Measure bore, OD, and width with calipers before confirming — even when the number looks readable.

Buying sealed (2RS) to replace open bearings without checking width

A sealed bearing runs about 0.5–1 mm wider than the open equivalent. In tight motor end plates, that extra millimeter binds the shaft. Always check the sealed bearing's own dimension row, not the open spec.

Assuming generic and branded bearings carry identical load ratings

ISO dimensions are standardized. Load ratings are not. A lower-grade bearing with identical dimensions can have a dynamic load rating 20–40% below a premium brand's specification. For high-cycle applications, that difference matters in service life.

Common Failure Scenarios — and What the Size Chart Tells You

Bearing runs hot within hours of replacement

Usually a fit problem. Check OD first: did you install the same series? A 6205 sitting in a housing bored for a 6305 has 10 mm of radial clearance — the outer ring spins, fretting corrosion follows, and the housing seat is damaged within hours. The size chart shows you the OD difference immediately: 52 mm vs 62 mm.

Bearing noise increases gradually over weeks

Points to contamination or lubrication rather than a dimension mismatch — but the suffix column is still relevant. If you swapped from 2RS to ZZ to reduce cost, a metal shield does not exclude fine particles the way a rubber seal does. The suffix column tells you exactly what protection you actually have.

Thrust bearing fails under light axial loads

Usually means a single-direction 51100 was installed in a reversing application, or a radial bearing was put where a thrust bearing was needed. The T dimension column and C₀ value in the thrust chart give you the geometry and capacity immediately.

FAQ

Can I replace a 6205 with a 6305?

Only if you re-bore the housing from 52 mm to 62 mm. The shaft fit is identical (25 mm bore), but the housing requirement is completely different. The 6305 gives you a 52% higher load rating in exchange for that larger housing diameter.

The stamp on my bearing is unreadable. How do I identify it?

Measure bore, OD, and width with digital calipers. Match all three to a row in the size chart. If dimensions fall exactly on a row, that is your bearing. If they land between two series, check the R-series inch bearing chart — it is likely an inch size.

Do load ratings differ between SKF, NSK, and NTN for the same part number?

Yes, slightly. Major brands each publish their own calculated ratings for identical ISO part numbers. Differences are typically within 5%. For critical load calculations, always use the specific brand's current datasheet rather than a generic table.

How do I calculate bearing life from the load rating?

The L10 life formula is standardized under ISO 281: L10 = (C/P)³ × 10⁶ revolutions for ball bearings, where P is the applied dynamic load. Use our Bearing Life Calculator to run this automatically.

Where can I get a 6205 bearing?

Browse our 6205 product page for specifications and availability, or use the inquiry form on the homepage for bulk pricing.

Tips for Selecting the Right Bearing

01

Start with shaft diameter. Bore (d) is always first. Everything else follows.
02

Measure the housing directly. Housing bores wear over time. Measure the housing itself, not the old bearing's OD.
03

Match load direction to bearing type. Radial → ball or cylindrical roller. Axial → thrust. Combined → angular contact.
04

Check the speed limit before finalizing. Sealed bearings have a lower speed limit than open equivalents. Confirm your RPM is below the rated maximum for the specific variant you are ordering.
05

Verify all three dimensions when cross-referencing brands. Part number alone is not enough. d, D, and B must all match.

Conclusion

Bearing selection starts with three numbers: bore, outer diameter, and width. Match those to your shaft and housing, verify the load rating covers your application, confirm you are within the speed limit, and the bearing will fit and run.

Load ratings in this article are based on SKF Rolling Bearings Catalogue values. Always verify against the specific manufacturer's current datasheet for engineering calculations and safety-critical applications.
How to Read a Bearing Size Chart + Free Dimension Reference Tables

How to Read a Bearing Size Chart + Free Dimension Reference Tables

Picture of Robert Robert : May 25, 2026 4:02:41 AM

Bearing size charts are not complicated once you know the logic. The numbers follow a fixed pattern — and once you get one bearing number right,...

Bearing Selection Bearing Dimensions
Read More
Bearing Static vs Dynamic Load: C, C0, L10 Explained + Free Calculator

Bearing Static vs Dynamic Load: C, C0, L10 Explained + Free Calculator

Picture of Robert Robert : Aug 21, 2025 10:17:55 PM

Bearings play a vital role in machinery by ensuring smooth motion and reducing friction. Understanding load capacities, specifically static load vs...

Bearing Loads Static Load Dynamic Load static load vs dynamic load
Read More
Linear Bearings vs Rotary Bearings — Key Differences Explained

Linear Bearings vs Rotary Bearings — Key Differences Explained

Picture of Robert Robert : May 12, 2026 5:12:38 AM

Linear Bearings vs Rotary Bearings — Key Differences Dimension ▶ Linear Bearing ▶ Rotary Bearing Motion type TranslationBack-and-forth...

Rotary Bearings linear bearings
Read More