Wear Parts

Wear parts (also referred to as wear-and-tear components or consumables) are an umbrella term for automotive components that have a relatively short service lifespan and require regular inspection and replacement due to natural wear, ageing, or harsh operating environments. The concept of wear parts extends beyond routine maintenance and servicing into regulatory definitions—China's National Standard GB/T 29632 ("Scope of Main Parts and Components and Warranty Certificate for Household Automotive Product Repair, Replacement and Return") classifies consumables as a distinct category, with their warranty periods determined by the manufacturer and explicitly stated in the warranty certificate, typically shorter than the comprehensive vehicle warranty.

Definition and Regulatory Status

Under the "Provisions on the Liability for Repair, Replacement and Return of Household Automotive Products" (effective 1 January 2022), if a quality defect arises in a passenger car within the warranty period, or in consumable parts within their specific warranty coverage, consumers are entitled to produce their warranty certificate for free repairs (inclusive of labour and parts) at an authorised repairer. The GB/T 29632 standard cited by this regulation clearly outlines the scope and categories of consumable parts, preventing manufacturers from arbitrarily classifying regular components as wear parts and setting overly short warranty terms to skirt warranty liabilities. Crucially, the overall vehicle warranty period does not apply uniformly to all components: with the exception of consumable wear items, all major components carry a standard warranty of 3 years or 60,000 kilometres.

Common Classifications of Wear Parts

Automotive wear parts are broadly classified into three main groups based on vehicle systems: engine wear parts, chassis wear parts, and body wear parts.

In terms of operational function, common wear-and-tear items primarily include the following:

• Filtration System: Engine oil filter, air filter, fuel filter, and cabin air-con filter. Among these, the engine oil filter is typically renewed alongside the engine oil every 5,000 km, while the engine air filter is recommended to be cleaned every 5,000 km and replaced every 20,000 km.

• Ignition System: Spark plugs. These directly influence engine acceleration performance and fuel economy, generally requiring replacement every 30,000 km; they should be inspected immediately if sluggish acceleration or power loss is experienced during driving.

• Braking System: Brake pads and brake discs (rotors). Brake pads must be replaced when the friction lining thickness drops below 0.6 cm, typically lasting around 30,000 km under normal driving conditions. Brake discs have a designated minimum thickness safety limit (e.g. 19 mm for most passenger vehicles) and must be replaced immediately once worn past this threshold.

• Tyres: Explicitly classified under regulations as consumable items. Tyres must be replaced when the tread depth wears down to 1.6 mm, when sidewall cracks or bulges develop, or when the specified service mileage is reached. For all-wheel-drive (AWD) and 4WD vehicles, the rolling radius difference between new and worn tyres must be strictly maintained within ≤3% to prevent permanent damage to the differential.

• Electrical and Rubber Components: Car battery (typically tested and replaced as needed every 2 years), windscreen wiper blades (replaced once streaking or chattering occurs), fuses, and various drive belts (such as the timing belt, typically replaced at 60,000 to 80,000 km).

Furthermore, workshop technical specifications mandate that the timing system (an integrated assembly comprising the timing belt/chain, tensioner, idler pulley, and water pump) be replaced as a complete kit to prevent catastrophic secondary engine damage caused by piecemeal component renewal. For the braking system, brake pads and brake discs on the same axle must always be replaced in axle pairs to guarantee balanced braking performance.

Key Usage and Maintenance Guidelines

The service intervals for wear parts depend heavily on driving habits, operating environments (intervals are noticeably shorter in high-temperature and high-humidity climates), and vehicle load conditions; actual replacement schedules should always follow the owner's manual and on-site physical inspection findings. Regularly checking the health of wear-and-tear parts and replacing degraded components promptly are crucial to ensuring vehicle roadworthiness and extending vehicle longevity. Safety-critical components, especially the braking system and tyres, must be prioritised during every routine service inspection.