6203DUM18A 17x40x12mm Tensioner Pulley Bearing – Deep Groove Ball Bearing for Automotive Belt Drive Systems

Product Overview

The 6203DUM18A is a precision single‑row deep groove ball bearing specifically engineered for automotive tensioner pulley and idler applications. With its compact dimensions of 17x40x12mm, this bearing provides reliable radial load support, low friction, and quiet operation – essential for maintaining proper belt tension in engine accessory drive systems, including alternators, water pumps, air conditioning compressors, and power steering pumps.

Built to withstand the demanding conditions of modern internal combustion and hybrid vehicles, the 6203DUM18A features a C3 radial internal clearance, dual rubber seals, and a lightweight nylon cage. Its non‑standard design offers enhanced durability and resistance to contamination, ensuring extended service life and reduced maintenance even under high‑speed, high‑temperature, and cyclic load conditions.

Technical Specifications

Design & Construction Features

Deep Groove Raceway Geometry – Optimised for high radial load capacity and low running torque, the deep groove design also permits moderate axial loads in both directions, making it ideal for tensioner pulleys that experience variable belt forces and pulley misalignment.

GCr15 Chrome Steel – Manufactured from vacuum‑degassed, high‑carbon chromium bearing steel, the 6203DUM18A delivers superior hardness (HRC 60–65), exceptional wear resistance, and excellent rolling contact fatigue strength, ensuring reliable performance over millions of belt cycles.

2RS Rubber Seals – Integrated contact seals on both sides provide effective barrier against dust, dirt, and moisture ingress while retaining the pre‑filled grease. The NBR seals are formulated for automotive under‑hood temperatures (‑40°C to +120°C) and resist degradation from engine oil and coolant.

Lightweight Nylon Cage – The glass‑fibre reinforced polyamide cage reduces centrifugal forces, minimises friction, and allows higher operating speeds. Its self‑lubricating properties contribute to lower heat generation and improved overall efficiency.

C3 Radial Internal Clearance – The C3 clearance ensures stable operation when the bearing is press‑fitted onto the pulley shaft and experiences thermal expansion during engine warm‑up, preventing premature seizure or excessive preload.

Materials & Quality Assurance

All 6203DUM18A bearings undergo 100% quality inspection, including dimensional accuracy, radial runout, noise and vibration testing (V3/V4 standards available), seal leakage checks, and torque measurement, in compliance with ISO 9001 and IATF 16949 standards.

Applications

The 6203DUM18A is specifically developed for automotive belt drive tensioning systems, but its versatility extends to:

• Engine Timing Belt Tensioners – Maintains correct belt tension for camshaft and crankshaft synchronisation

• Accessory Belt Idler Pulleys – Guides and tensions serpentine belts in alternator, AC compressor, and power steering circuits

• Hybrid and Electric Vehicle Auxiliary Drives – Electric oil pumps, coolant pumps, and fan drives

• Industrial Conveyor Pulleys – Light‑to‑medium duty radial load applications

• Agricultural and Off‑Highway Equipment – Belt‑driven attachments
  
  
  

  Contacts:

  Company	WUXI MUFA TECHNOLOGY CO.,LTD.
  Sales	Alice Wong
  Email	[email protected]
  WhatsApp	+86 13771165326
  WeChat	mufatec-bearings

   

Share this product to:     Let more people see your product