Should Brake Pads Be Replaced at 4mm?
3 Answers
Brake pads at 4mm do not need to be replaced. Here is relevant information about brake pads: 1. Classification of brake pads: Asbestos brake pads (mostly obsolete), semi-metallic brake pads, low-metallic brake pads, NAO formula brake pads, ceramic brake pads, and NAO ceramic brake pads. 2. Ceramic brake pads vs. traditional brake pads: In traditional brake pads, metal is the primary material generating friction, providing strong braking force but with significant wear and a tendency for noise. After installing ceramic brake pads, no abnormal noise occurs during normal driving. Since ceramic brake pads do not contain metal components, they avoid the metal-on-metal friction noise between traditional metal brake pads and their counterparts (i.e., brake pads and brake discs). 3. Stable friction coefficient: Ordinary brake pads often use immature friction materials, with excessively high friction coefficients leading to unsafe factors such as loss of directional control during braking, pad burning, and disc scratching. Even when the brake disc temperature reaches as high as 650 degrees, the friction coefficient of ceramic brake pads remains around 0.45-0.55, ensuring the vehicle maintains good braking performance.
I'm a seasoned auto repair shop veteran who often gets asked about brake pad thickness. Generally, new brake pads are about 10-12mm thick and need replacement when worn down to 2-3mm, so 4mm still has some life left – but don't get overconfident. The key factor is driving conditions: frequent braking in city traffic accelerates wear, meaning 4mm pads might reach the danger zone within a few thousand kilometers; highway driving with less braking extends their lifespan. Always inspect brake rotors too – warped or grooved surfaces affect braking performance and can damage pads faster. Safety first: I recommend monthly measurements with simple calipers or free professional inspections. Pro tip: wet winter conditions reduce braking efficiency – replacing pads early saves more hassle than waiting too long.
The one in charge manages the budget, while I take care of the family's concerns. Replacing a set of brake pads costs a few hundred bucks—not expensive. But if you wait until they're down to 4mm, the brake discs could get damaged, costing you over a thousand. For example, my neighbor last year stubbornly kept using his pads at 4mm, resulting in failed emergency braking and doubled repair costs. Normal wear consumes 70% of the thickness from 12mm to 4mm, with the remaining 30% wearing out faster. According to the manual, some car models recommend replacement at around 5mm for the best cost-effectiveness. Don’t lose big for small savings—choose reputable brands for better durability. Driving habits also matter: aggressive drivers wear pads faster, and delaying replacement wastes more fuel. Check pad thickness regularly and address issues early—it’s worth the time.
