MR18307 18x30x7mm Bicycle Hub Thin Wall Deep Groove Ball Bearing

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When your equipment demands smooth, reliable rotation under load, the MR18307 deep groove ball bearing delivers exceptional performance in a compact 18x30x7mm envelope. This single-row radial bearing is engineered for applications where precision, durability, and contamination resistance are critical—from high-performance bicycle hubs to industrial machinery and precision instruments.

Key Features:

• Direct Replacement for 6903 in Leading Hubs
  The MR18307 is commonly used to replace bearings marked 6903 in front hubs from DT Swiss, Giant, and Bontrager, though the inner diameter of the MR18307 is 1mm larger than a standard 6903. This makes it a direct drop-in upgrade for many high-performance bicycle wheels.

• Exceptional Load Capacity
  With a dynamic load rating of 4.6 kN and a static rating of 2.6 kN, the MR18307 delivers robust load-carrying capability in a compact 18x30x7mm package. This load capacity makes it suitable for bicycle hubs, bottom brackets, and industrial equipment.

• Superior Contamination Protection
  The double seals provide superior protection against dust, water, and debris, making the MR18307 ideal for bicycle hubs, bottom brackets, and other applications exposed to the elements. The 90% grease fill ensures long-lasting lubrication even in demanding conditions.

• Multiple Precision Grades
  Available in ABEC-1, ABEC-3, and ABEC-5 precision grades, the MR18307 can be matched to your specific performance requirements. ABEC-3 bearings offer improved quality over ABEC-1, while ABEC-5 provides ultra-tight tolerances for high-precision applications.

• High Speed
  The deep-groove design and precision manufacturing enable the MR18307 to achieve limiting speeds up to 2,700 RPM with grease lubrication, making it suitable for a wide range of rotating equipment.
• Corrosion Resistance Options
  The si3n4 ceramic hybrid variant provides enhanced corrosion resistance, making it suitable for wet and humid environments.

Applications

The MR18307 deep groove ball bearing is a versatile component trusted across numerous industries:

• Bicycle Hubs – The primary application. Used as a front hub bearing in many high-performance bicycle wheels, including DT Swiss, Giant, and Bontrager models. Compatible with mountain bikes, road bikes, gravel bikes, hybrid bikes, touring bikes, and e-bikes.

• Bottom Brackets – Used as a bottom bracket bearing for older square taper BBs.

• Pivot Bearings – Can be used as a pivot bearing, though the MAX-type version is better suited for suspension use.