SEMI-METALLIC Brake Pads: Meaning, Benefits, Lifespan & More
Semi-metallic brake pads are a type of brake pad composed of 30-65% metal particles like copper, iron, or steel bonded with resins and other friction modifiers. The metal particles provide superior heat transfer and wear resistance compared to organic pads, while the resins provide the friction that stops the vehicle.
Semi-metallic pads work by using the friction material on the pad to grip the rotor surface when the brakes are applied. The friction creates heat, slowing the rotor and vehicle down. The metal particles conduct away the heat and prevent brake fade at high temperatures. Semi-metallics also withstand wear better than organic pads.
The origins of semi-metallic pads trace back to 1961, when the British company Ferodo introduced sintered metal pads using powder metallurgy techniques. This produced a more durable friction material. Semi-metallic pads gained widespread use in the 1980s and continue to be a popular choice today, especially for high performance applications.
Benefits of Semi-Metallic Pads
Semi-metallic brake pads offer several key benefits compared to other pad types:
Durability
The metal fibers mixed into the friction material make semi-metallic pads very durable and resistant to heat buildup [1]. This allows them to withstand repeated heavy braking without wearing down as quickly as organic pads.
Noise Reduction
Semi-metallic pads tend to be quieter than purely metallic pads. The friction material dampens vibration and noise compared to all-metal pads [2].
Heat Dissipation
The metallic content conducts heat away from the rotor and pads as you brake. This prevents brake fade caused by overheating [3]. Semi-metallic pads can withstand more heat than organic pads before fading occurs.
Drawbacks of Semi-Metallic Pads
While semi-metallic brake pads have some benefits, they also come with some drawbacks to consider. One of the main downsides is that semi-metallic pads tend to produce more brake dust than other pad materials like ceramics. The high amounts of metal in semi-metallic pads lead to more dust when the brakes are applied (Semi-metallic vs ceramic brake pads — difference explained).
The metallic composition can also lead to potential corrosion issues in some environments, especially those with salted winter roads. The metals can start to corrode over time with exposure to salt, moisture, and winter conditions (The Pros and Cons of Different Brake Pad Materials for Fleet Vehicles).
Finally, semi-metallic brake pads tend to be noisier than other pad types, especially when they are cold. Drivers may notice squeaking, grinding, or other noises when first using the brakes after the vehicle has been parked overnight or for an extended period (Semi-metallic vs ceramic brake pads — difference explained). The high metal content leads to more vibration and noise until the pads warm up.
Ideal Uses for Semi-Metallic Pads
Semi-metallic brake pads are best suited for certain high-performance driving situations where maximum braking power and heat dissipation are needed. Some of the ideal uses for semi-metallic brake pads include:
High performance driving/racing – The metallic compounds in semi-metallic pads can withstand extremely high temperatures without fading. This makes them well-suited for track days and competitive motorsports where brakes are used heavily (https://www.bridgestonetire.com/learn/maintenance/ceramic-vs-metallic-brake-pads/).
Towing heavy loads – Semi-metallic pads offer strong braking power for safely stopping vehicles towing heavy trailers or cargo. The metallic pads have high fade resistance when brakes get hot from frequent use towing (https://www.autozone.com/diy/brakes/ceramic-vs-metallic-brake-pads).
Commercial vehicles – Trucks, taxis, delivery vans and other commercial vehicles often utilize semi-metallic pads. The robust construction stands up to heavy brake use over high mileage. Metallic compounds also resist brake fade from prolonged braking when carrying loads (https://www.advicsaftermarket.com/technical-resources/tech-tips/ceramic-vs-semi-metallic-brake-pads-how-they-work-and-what-theyre-made-of/).
Alternatives to Semi-Metallic Pads
While semi-metallic pads are a popular choice, there are other brake pad materials to consider as alternatives:
Organic Pads
Organic brake pads use fibers, fillers, binders and lubricants in their formulation. They tend to produce less noise and dust compared to semi-metallic pads. Organic pads also typically provide better cold weather performance. However, their friction when hot is not as stable as semi-metallic pads. Organic pads wear faster and need to be replaced more often. They’re a good choice for light-duty use.
According to this source, organic brake pads are inexpensive but don’t perform as well for high performance driving.
Ceramic Pads
Ceramic brake pads use ceramic fibers in their composition instead of metallic fibers. This makes them very hard and durable while still being relatively lightweight. Ceramic pads provide consistent braking power in cold and hot conditions. They produce less dust and noise than semi-metallic pads. However, ceramic pads tend to be more expensive.
Sintered Pads
Sintered brake pads are manufactured through high heat and pressure without any organic compounds. This gives them high mechanical strength and fade resistance at elevated temperatures. Sintered pads provide effective braking performance for repeated heavy braking. However, they tend to produce more noise and dust. Sintered pads also don’t perform as well in cold weather and wet conditions.
Cost Comparison to Other Pads
When it comes to price, semi-metallic brake pads tend to fall somewhere between organic and ceramic brake pads. Semi-metallic pads are typically more expensive than organic pads, which are the most budget-friendly option. However, semi-metallic pads are cheaper than premium ceramic brake pads. Here are some typical price comparisons:
On average for the front brakes:
- Organic pads: $20-$25
- Semi-metallic pads: $25-$35
- Ceramic pads: $40-$50
So while more affordable than ceramics, semi-metallic pads come at a small premium over basic organic pads. However, semi-metallic pads offer better braking performance and longer pad life than organics, making them a good value for the extra cost. When pricing brake jobs, expect to pay around $10-15 more for semi-metallic pads compared to basic organics.
Lifespan and Replacement Intervals
Semi-metallic brake pads generally last longer than organic pads before needing replacement. While organic pads may need replacement every 20,000-40,000 miles, semi-metallic pads can often go 30,000-70,000 miles before needing new pads.
The lifespan of semi-metallic brake pads can vary substantially depending on driving conditions, vehicle type, and driving style. Aggressive driving with heavy braking will wear out pads quicker. Stop-and-go city driving also puts more stress on pads compared to highway driving.
Larger vehicles like trucks that are heavier and need more braking power will wear out semi-metallic pads faster than a smaller sedan. Sports cars and high-performance vehicles also demand more from brake pads leading to quicker wear.
In ideal conditions, semi-metallic pads may be able to go up to 70,000 miles before needing replacement. But for most drivers, it’s reasonable to expect to need new semi-metallic pads every 40,000-60,000 miles.
It’s important to regularly inspect brake pads for wear and have them replaced when they reach the minimum thickness. Waiting too long can damage rotors and calipers. Replacing pads before they are fully worn also allows the new pads to properly bed-in for maximum performance and braking power.
Installing and Bedding Semi-Metallic Pads
Installing new semi-metallic brake pads and properly bedding them in is crucial for safety and performance. Here is a step-by-step guide to installing and bedding semi-metallic brake pads:
Step 1: Make sure you have the proper tools – jack and jack stands, socket set, brake cleaner, brake lube, torque wrench, etc. Refer to your vehicle service manual for proper procedures.
Step 2: Safely jack up the vehicle and secure with jack stands. Remove the wheels to access the brake calipers and pads.
Step 3: Remove the old brake pads, caliper bolts, anti-rattle clips and hardware. Clean the caliper and mounting bracket thoroughly with brake cleaner.
Step 4: Install the new pads, anti-rattle clips and hardware according to manufacturer specifications. Apply brake lubricant to contact points. Reinstall the caliper and torque bolts to spec.
Step 5: Repeat steps on all wheels. Refit the wheels and lower the vehicle.
Step 6: Before driving, pump brakes to restore proper pad-rotor contact. The brakes should firm up quickly.
Bedding Process: The bedding process should be performed right after installing new pads to transfer an optimal transfer layer between pads and rotors. Here are the steps:
– Accelerate to approximately 40 mph and apply firm pressure on the brakes until almost completely stopped. Repeat approximately 10-15 times, allowing the brakes to cool for a minute between stops. This helps transfer material evenly across pad surfaces.
– Accelerate to highway speeds, then apply brakes normally until you slow down to around 25 mph. Repeat 5-8 times, cooling brakes between each cycle. This deposits a uniform layer across the rotor surfaces.
– Avoid using brakes aggressively for the next 100-200 miles to allow for proper curing of the brake pads. The brakes will feel firmer after this period.
Properly bedding semi-metallic pads helps ensure safe, consistent braking performance and maximizes pad and rotor life.[1]
Maintenance Tips
Proper maintenance is key to getting the most out of your semi-metallic brake pads and rotors. Here are some tips to follow:
Check pad thickness regularly, at least every other oil change or 5,000-10,000 miles. Pads should be replaced when they reach 2-3mm of remaining thickness. Use a gauge to measure at multiple spots on the pad.[1]
Clean any brake dust buildup on wheels or rotors with every pad change. Excessive dust can cause runout, vibration, and uneven wear. Use brake cleaner and a brush to scrub away built-up deposits.[2]
Check brake fluid level and change fluid at recommended intervals. New fluid helps maintain optimal braking performance.[3]
Inspect rotors for thickness variation, cracks, grooves and hot spots. Resurfacing or replacing rotors helps prevent pulsing brakes and uneven wear on pads.
Overall, keeping your semi-metallic brake system clean and monitored for wear ensures safe, consistent braking performance.
The Future of Semi-Metallic Brake Pads
The future of semi-metallic brake pads is likely to see some changes as new formulas and materials become more widely adopted. Some key trends include:
Development of New Formulas – Manufacturers are working to tweak the metal and filler ratios in semi-metallic pads to optimize braking performance. For example, increased copper content can improve conductivity and heat dissipation (Brake Pad Technology – What’s New In Brake Pads). Expect to see continued innovations in semi-metallic brake pad formulas in coming years.
Shift Towards Other Materials – Alternatives like ceramic and organic brake pads are gaining popularity, especially in high-performance applications. The market share for semi-metallic pads is projected to decline from 73% in 2022 to 70% by 2031 as other materials gain adoption (Semi Metallic Brake Pads Market Size, Forecasting Growth). Still, semi-metallic is expected to remain the dominant choice for most drivers.