Are All 6203 Bearings the Same? Size & Variant Guide

Not all 6203 bearings are the same. While every standard metric 6203 bearing shares identical envelope dimensions of 17 mm bore, 40 mm outside diameter, and 12 mm width, they are not universally interchangeable across every industrial application.

A bearing part number establishes physical outer dimensions under international standards, but it does not dictate seal variants, internal clearance, material quality, or brand manufacturing tiers. Installing an open bearing where a double-shielded 6203 ZZ is required can lead to rapid contamination and premature failure, even though both fit the exact same shaft and housing.

Understanding what the 6203 number fixes and what it leaves open ensures you select the exact component your machinery requires. In Pakistan, HI-TEC BEARINGS provides technical verification and bulk supply for precision 6200 Series parts to prevent costly operational downtime.

Are all 6203 bearings the same size?

All 6203 bearings share identical boundary dimensions - 17 mm bore, 40 mm outside diameter, and 12 mm width - but they are not universally interchangeable due to variant differences. International standards such as ISO 15 define the basic physical envelope for radial rolling bearings^[1][2]. Under this standardized numerical system, the prefix 6 specifies a deep groove ball bearing, the digit 2 defines the 6200 Series proportion, and the final digits 03 establish the 17 mm inner bore diameter^[1][2]. Every manufacturer producing a metric 6203 component builds it to fit a 17 mm shaft and a 40 mm housing bore with a 12 mm width^[1][2].

However, identical boundary measurements do not make every 6203 bearing functionally equal. A bearing part number fixes physical dimensions, but it does not specify seal variants such as 6203 ZZ or brand quality tiers like HI-TEC SILVER. Basic part numbers represent open bearings without protective closures. If your equipment operates in a dusty agricultural environment or high-speed motor housing, substituting an open 6203 for a shielded or sealed variant will result in rapid lubricant loss and premature failure. Furthermore, internal construction details - including dynamic load ratings, ball precision, steel quality, heat treatment, and internal clearance classes like C3 - vary significantly between standard budget options and premium lines^[2].

When sourcing replacement parts across Pakistan, matching the three envelope dimensions is only the first step. Maintenance managers must also evaluate environmental sealing, thermal expansion requirements, and manufacturing tiers to ensure long service life in industrial machinery.

Parts in this article

What are the exact dimensions of 6202, 6203, and 6204 bearings?

Adjacent 6200 Series parts differ in size: 6202 measures 15x35x11 mm, 6203 measures 17x40x12 mm, and 6204 measures 20x47x14 mm. While all three belong to the single-row deep groove ball bearing family, each step up in the series increases shaft diameter, outer boundary housing dimensions, overall width, and load-carrying capacity.

The 6203 bearing features a 17 mm bore, 40 mm outside diameter, and 12 mm width in the HI-TEC SILVER range. Selecting between these adjacent sizes depends entirely on shaft step requirements and mechanical load specifications. Choosing an incorrect size by even a single millimeter makes installation physically impossible without damaging equipment shafts.

The table below outlines the exact dimensional boundaries, series designations, and catalog variants for these common 6200 Series parts available through HI-TEC BEARINGS:

For complete dimension matrices across the entire product line, consult our comprehensive 6200 series bearing size chart. Understanding these physical increments ensures procurement teams order the correct part number before mounting.

What does 6203 ZZ mean on a bearing?

The suffix ZZ on a 6203 bearing specifies double metal shields (6203 ZZ) for dust protection. In standard bearing nomenclature, letters following the base numerical designation indicate protective closures, seal types, or internal clearance modifications. A plain 6203 bearing is supplied open, leaving the internal steel balls and raceways exposed to the ambient environment and requiring external lubrication.

Adding suffixes alters physical protection without altering boundary dimensions^[2]:

• ZZ Suffix (2x Shield): Indicates non-contact metallic shields pressed into the outer ring on both sides. The 6203 ZZ variant retains factory grease while excluding dry airborne contaminants like dust and debris without increasing rotational friction^[2].
• 2RS / 2RS E Suffix (2x Rubber Seal): Indicates contact synthetic rubber seals fitted on both sides. Rubber contact seals provide superior liquid and moisture resistance compared to metal shields, though with slightly higher friction^[2].
• Clearance Suffixes (e.g., C3): Indicates radial internal clearance greater than normal, accommodating thermal expansion in electric motors and high-temperature machinery^[2].

Selecting the right variant prevents premature breakdown. A double-shielded 6203 ZZ bearing operates efficiently in dry electric motor housings, whereas liquid-exposed pumps require contact rubber seals like 6202 2RS or 6204 2RS E.

HI-TEC confirms exact part specifications, price, and availability directly via WhatsApp (+92-348-5563390). Industrial buyers across Pakistan can consult our technical support team to verify exact suffix compatibility, seal requirements, and delivery times for wholesale orders.

Frequently Asked Questions

Are all 6203 bearings the same size?

Yes, all standard metric 6203 bearings share identical boundary dimensions of 17 mm bore, 40 mm outside diameter, and 12 mm width. However, they are not universally interchangeable because seal variants (such as open, 6203 ZZ, or 2RS), internal clearance classes, and quality tiers like HI-TEC SILVER differ based on operational demands.

What are the exact dimensions of a 6203 bearing?

A 6203 deep groove ball bearing features an inner bore diameter of 17 mm, an outside diameter (OD) of 40 mm, and a width of 12 mm. These envelope dimensions are standardized globally under ISO 15.

What is the difference between 6202, 6203, and 6204 bearings?

The primary difference lies in physical dimensions and load capacity. The 6202 bearing measures 15x35x11 mm, the 6203 bearing measures 17x40x12 mm, and the 6204 bearing measures 20x47x14 mm. Each step up in series number accommodates a larger shaft diameter and heavier operational loads.

What does 6203 ZZ mean on a bearing?

The ZZ suffix on a 6203 ZZ bearing indicates that the component is equipped with two non-contact metal shields, one on each side. These shields protect the internal balls and raceways from dust and solid contaminants while retaining factory grease inside.

References

1. ISO 15:2017 - Rolling bearings - Radial bearings - Boundary .... https://webstore.ansi.org/standards/iso/iso152017 (2026-10-30)
2. [PDF] INTERNATIONAL STANDARD ISO 15 - ANSI Webstore. https://webstore.ansi.org/preview-pages/ISO/preview_ISO+15-2017.pdf (2026-10-30)