Wheels Manufacturing Sealed Steel Bearings
Wheels Manufacturing

Wheels Manufacturing Sealed Steel Bearings

In Stock

Wheels Manufacturing SB-6903 sealed steel cartridge bearings (17x30x7mm) deliver ABEC 3 precision and durable steel construction. Sold as a bag of two — ideal for bottom brackets, hubs and routine rebuilds.

Add to Cart
🚚 Fast Shipping 🔒 Secure Checkout ↩ Easy Returns

Product Details

Overview & Technology

Wheels Manufacturing SB-6903 sealed cartridge bearings are engineered for reliable, long-lasting rotation in demanding bike applications. These steel bearings are precision-made to the 6903 size spec (17x30x7mm) and carry an ABEC 3 tolerance rating for consistent performance across hubs, bottom brackets and other rotating assemblies. The bearings are fully sealed to keep out dirt and moisture, while hardened steel races and chrome steel balls offer toughness and predictable rolling resistance. Their compact 17x30x7mm footprint makes them a direct replacement in many factory assemblies — sold as a bag of two to cover paired positions during a service or rebuild.

Key Features & Construction

Material & build: 100% steel construction — hardened steel races and chrome steel balls — for durability and wear resistance. The sealed cartridge design retains lubrication and shields internal components from grit and water, extending service intervals in real-world riding conditions. Precision & performance: ABEC 3 rating guarantees consistent tolerances and dependable rolling characteristics without the premium cost of higher ABEC grades. The 17x30x7mm dimension (6903) is an industry-standard size, making these bearings a versatile, cost-effective replacement for many applications.

Fit, Installation & Compatibility

These SB-6903 bearings measure 17 x 30 x 7 mm and are intended as direct replacements where 6903 bearings are specified — common uses include certain bottom bracket assemblies, hub axle interfaces, idler wheels and other rotating parts on bikes. Confirm the bearing number or measure the inner/outer diameter and width before purchase. Installation is straightforward with the right tools: use a bearing press or appropriate drift to press the bearing squarely into its bore. Avoid hammering directly on the bearing race; use a sleeve that contacts only the outer race when installing. A light application of grease on the outer shell can ease seating and prevent corrosion.

Who This Is For

This sealed cartridge bearing pair is perfect for home mechanics, workshop technicians and riders who want a reliable, budget-friendly replacement bearing. Ideal for mountain bikers and commuters who face mud and wet conditions, these sealed steel bearings prioritize durability and low maintenance. If you shop for long-lasting, no-fuss replacement bearings for routine overhauls of hubs or bottom brackets, the SB-6903 offers an excellent balance of value and dependable real-world performance.

Key Features

  • ✓ 6903 size: 17 x 30 x 7 mm — industry-standard replacement dimension
  • ✓ Sealed cartridge design keeps out dirt and retains lubrication
  • ✓ Hardened steel races and chrome steel balls for long wear life
  • ✓ ABEC 3 tolerance for consistent, reliable rolling performance
  • ✓ Sold as a bag of two — ready for paired replacements
  • ✓ Perfect for hubs, certain BBs, idlers and small rotating assemblies
  • ✓ Lightweight package — shipping dims 3.2" x 1.3" x 0.2", 0.05 lb

Specifications

Bearing Grade ABEC 3
Number 6903
Bearing Dimensions 17x30x7mm
Material Steel

Product Identifiers

Vendor Item # SB-6903
UPC 836572002506

Frequently Asked Questions

What does 6903 mean and will it fit my component?

6903 is the bearing size code: 17mm inner diameter x 30mm outer diameter x 7mm width. It will fit any application that specifies a 6903 bearing. Always verify your component's required bearing number or measure the bore before ordering.

Are these bearings pre-greased and sealed?

Yes — SB-6903 bearings are sealed cartridge units with grease pre-installed at the factory. The seals help keep contaminants out and the grease in, reducing maintenance frequency compared with open bearings.

Can I use these in high-load applications or downhill bikes?

These bearings are steel and robust for general mountain bike use, but their ABEC 3 rating and sealed cartridge design are aimed at durability and reliability rather than extreme high-speed precision. For heavy-duty gravity applications you may prefer specialty bearings rated for higher loads or with different internal designs.

How do I install these without damaging them?

Use a bearing press or a socket that contacts only the outer race to press the bearing squarely into the bore. Do not hammer directly on the bearing. Lightly grease the outer shell for corrosion protection and ensure the seat is clean and free of burrs before installation.

Can I replace one bearing or should I replace both?

Where bearings are used in pairs (such as many hub or BB assemblies), replacing both at the same time is recommended to ensure even wear and consistent performance. These are sold as a bag of two to make paired replacement convenient.

How long will these bearings last?

Service life depends on conditions and maintenance — sealed bearings last longer in wet and dirty environments than open bearings. With proper installation and typical trail or commuter use, you can expect many hundreds to thousands of miles before noticeable wear, but inspect and service as needed.

Buying Guide

When buying replacement sealed cartridge bearings, confirm the bearing number (e.g. 6903) or measure the inner diameter, outer diameter and width. Choose sealed units for wet and muddy riding — they hold grease and block contaminants better than open bearings. Check ABEC ratings for precision; ABEC 3 provides dependable tolerances for most bike uses without the premium cost of high-ABEC bearings. Also consider whether your application expects paired replacements (hubs, some BBs). Buying a bag of two like the SB-6903 simplifies service and ensures matched wear for predictable performance.

Ready to order?

Shop with confidence at Scenders — premium cycling parts, fast shipping.

View Full Product