Semi-metallic brake pads use a friction material built around steel fiber and other metallic content, typically making up half or more of the pad's volume, bound together with resins, graphite lubricants and filler. The steel gives them strong resistance to brake fade under hard, repeated stops, at the cost of being noisier, dustier and harder on rotors than a ceramic or organic pad.
What Semi-Metallic Pads Are Actually Made Of
A semi-metallic friction compound is built around steel fiber and steel wool, blended with graphite, iron particles and resin binders. According to EBC Brakes' own technical material, steel fibers constitute half or more of the brake pad's volume in a semi-metallic formulation. The material was originally adopted across the industry as an asbestos replacement, and the steel fiber also doubles as an inexpensive filler during manufacturing, which is part of why semi-metallic pads remain common factory equipment on trucks and work vehicles.
That steel content is the whole story with this pad type. It is what makes semi-metallic pads behave differently from an organic (non-asbestos organic, or NAO) pad built mostly from rubber, glass and fiber, or a ceramic pad built around ceramic fibers and copper-free fillers.
The Advantages: Why Shops Still Spec Semi-Metallic Pads
Steel conducts heat far better than the organic and ceramic fibers used in other pads. In a semi-metallic compound, that steel pulls heat away from the pad face and helps move it into the caliper and surrounding air rather than letting it build up at the friction surface. That is the main reason semi-metallic pads hold up well under sustained hard braking - descending a long grade, towing, or repeated stops at a track day - where an organic pad can lose stopping power as it overheats.
- Fade resistance. The metallic content keeps the friction surface working at temperatures that would soften a purely organic compound.
- Consistent pedal feel. Semi-metallic material is less compressible than a soft organic pad, so the pedal stays firmer under hard use instead of going long.
- Lower material cost. Steel fiber is a cheaper filler than the ceramic fibers used in premium pads, which is why semi-metallic pads are common OEM equipment and tend to sit at the budget end of the aftermarket lineup.
For a driver who tows, hauls, or drives a performance car hard, those traits matter more than noise or dust. See our guide to best brake pads for towing for how that trade-off plays out on a loaded vehicle.
The Drawbacks: Noise, Dust, and Rotor Wear
The same steel that resists fade creates the three complaints every semi-metallic owner eventually has. EBC's technical page is direct about all three: semi-metallic pads "are often noisy and require good shim hardware to quieten them down," they are "also dustier," with dust that is darker and made of iron or steel rather than the lighter dust from an organic or ceramic pad, and they "will wear rotors faster" because of how aggressively the compound bites.
There is also a manufacturing wrinkle: bonding steel friction material to a steel backing plate is effectively welding steel to steel, which is harder to do reliably than bonding an organic or ceramic compound. Pad makers address it with mechanical retainers and multi-layer shims rather than adhesive alone - which is also the hardware that controls the noise. A pad kit that skips good shims is the one that squeals. Our brake hardware kits collection covers the shims, clips and anti-rattle hardware that keep any pad, semi-metallic included, quiet.
If brake dust on your wheels is the main concern, read what causes brake dust for why semi-metallic dust looks and behaves differently from ceramic dust.
Semi-Metallic vs. Ceramic vs. Organic
| Trait | Semi-Metallic | Ceramic | Organic (NAO) |
|---|---|---|---|
| Fade resistance | Strongest of the three | Good | Weakest under sustained heat |
| Noise | Noisiest without good shims | Quietest | Quiet |
| Dust | Most, dark iron/steel dust | Least, lighter-colored dust | Moderate |
| Rotor wear | Fastest rotor wear | Gentlest on rotors | Gentle on rotors |
| Cold bite | Good once warmed | Good from cold | Good from cold |
| Typical use | Towing, trucks, performance | Daily commuter, most cars | Light-duty daily driving |
For most daily commuters, the quieter and cleaner ceramic compound is the better all-around choice; our guide on whether ceramic pads stop better walks through that comparison in more depth. For a vehicle that tows, hauls heavy loads, or sees track time, the fade resistance of semi-metallic is worth the extra noise and dust. The full decision tree, including brake-fade specific guidance, is in how to choose brake pads and what is brake fade.
The Copper Rule Changing Semi-Metallic Formulations
Older semi-metallic pads leaned on copper in the friction mix to help with heat transfer and noise damping, but copper brake dust washes off roads and into waterways, where it is toxic to fish. Washington State's Better Brakes law (RCW 70A.340) set a national benchmark: as of January 1, 2021, brake pads sold in Washington and California could not exceed 5% copper by weight, and starting January 1, 2025, that limit dropped to less than 0.5% copper by weight. The same law has required brake pads to contain 0.1% or less by weight of asbestos, hexavalent chromium, mercury, cadmium and lead since January 1, 2015. The EPA, automakers and brake manufacturers signed onto the same standard nationally through a memorandum of understanding, which is why copper-free semi-metallic formulations are now standard across the industry rather than a regional quirk. Look for the LeafMark symbol on the box - a Level N mark confirms a pad meets the full 2025 copper standard.
How to Tell What's Already On Your Car
There is no universal color code, but there are tells. Semi-metallic pads usually look gray to dark gray with visible metal flecks in the friction material, and the backing plate often shows surface rust where the pad has been in service, because the steel fiber in the compound itself can oxidize at the edges. Dust on the wheel face that is dark gray to black and wipes off gritty, rather than the lighter gray dust a ceramic pad leaves, is a strong sign the car is running semi-metallic. The pad box or the sticker on the original pad backing plate is the only fully reliable source - if you still have it, that print tells you the compound without guessing.
What to Replace Alongside a Semi-Metallic Pad Swap
Because semi-metallic pads wear rotors faster than ceramic or organic compounds, check rotor thickness and runout at every pad change rather than assuming the rotors are good for another cycle. If the rotors are already near minimum thickness or showing heat spotting from hard use, replace pads and rotors together rather than bedding new pads against a marginal rotor - our brake rotors collection is organized by vehicle fitment. Always replace the hardware kit (shims, clips, anti-rattle springs) with a semi-metallic pad job; it is the cheapest part in the box and it is what keeps a metallic compound from singing. Full pad-and-rotor kits in semi-metallic and ceramic compounds, including Power Stop, Akebono and Bosch lines, are in our brake pads and ceramic brake pads collections.
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Shop Brake Pads & Kits →Frequently Asked Questions
Are semi-metallic brake pads bad for rotors?
They wear rotors faster than ceramic or organic pads because the steel in the friction material is more abrasive against the rotor face. That does not make them unsafe - it means rotor thickness should be checked more often on a vehicle running semi-metallic pads.
Do semi-metallic brake pads squeal more?
Yes, more than ceramic or organic pads, unless the pad kit uses good shim and retainer hardware. The noise comes from the steel-to-steel bond between the friction material and the backing plate vibrating against the rotor; proper shims damp that vibration.
Why do semi-metallic pads make so much dust?
The dust is largely iron and steel shed from the friction material itself, which is why it looks darker and feels grittier on the wheel face than ceramic dust.
Are semi-metallic brake pads better for towing?
Generally yes. The steel content resists heat-related fade better than organic or ceramic compounds under the sustained braking load that towing and hauling create.
Do semi-metallic brake pads still contain copper?
Current production pads sold in the US are moving toward copper-free or near copper-free formulations under the national Better Brakes standard, which caps copper at under 0.5% by weight as of 2025. Older pads manufactured before the phase-out could contain significantly more.
Can I mix semi-metallic pads with ceramic pads front and rear?
It is common on vehicles where the front and rear axles see different heat loads, but check your vehicle's service information first - some ABS and brake-by-wire systems are tuned around a specific friction coefficient on both axles.
Sources
- Washington State Department of Ecology, Better Brakes Law - copper and heavy-metal phase-out thresholds and effective dates.
- EBC Brakes, Types of Brake Pads - Which Is Best - semi-metallic composition, noise, dust and rotor-wear characteristics.
- Tire Review, New Wagner Brake Website Showcases Technologies - Integrally Molded Insulator shim technology used to quiet metallic friction pads.