So, you've Changed your Mountain bike, Gravel / Road bike or E-bike to a fresh set of sintered (Full metallic) brake pads.
You were expecting incredible wet-weather performance, outstanding fade resistance, stronger braking power and a compound capable of lasting significantly longer than organic alternatives.
Instead, your first ride sounds like a flock of angry geese chasing a tractor through a scrapyard.
If your brakes have gone from silent to deafening after fitting sintered pads, don't panic. In most cases there is nothing wrong with the brake pads themselves. What you're hearing is a vibration problem caused by changes within the braking system.
This guide explains why it happens, why SRAM brakes can be particularly sensitive, and how to eliminate the noise properly.
When brake pads bed into a rotor, they leave behind a microscopic layer of friction material on the braking surface.
This is known as the transfer layer.
Organic, resin and semi-metallic compounds create a relatively soft and uniform transfer layer that helps damp vibration and creates smooth, predictable braking.
When everything is working correctly, the brake pad is not actually gripping bare steel. Instead, the pad is interacting with the transfer layer it has created on the rotor.
Problems often begin when riders switch directly from organic or semi-metallic pads to sintered pads without resetting the rotor surface.
Sintered pads are made from metallic particles fused together under extremely high heat and pressure. They are significantly harder than organic compounds and behave very differently under load.
If a rotor still contains residue from a previous compound, the new sintered pad is forced to work against an incompatible transfer layer.
Instead of producing smooth friction, the pad repeatedly grabs and releases at a microscopic level. This creates vibration throughout the rotor, caliper and frame.
That vibration is what you hear as brake squeal.
Organic compounds typically have a smooth, dark friction surface with a softer appearance. They generate a thick transfer layer and naturally damp vibration, making them the quietest compound available.
Semi-metallic compounds contain a blend of friction materials and metallic particles. The surface often appears slightly textured with visible metallic flecks.
Sintered compounds have a dense metallic structure created through heat and pressure. The friction surface usually appears rougher and more granular.
Trade-off: Because they are extremely rigid, sintered pads will amplify problems elsewhere in the braking system rather than masking them.
Many riders notice that SRAM brakes appear more sensitive to sintered compounds than other systems.
There are several reasons for this.
Traditional SRAM Centerline rotors are relatively lightweight and use a distinctive cut-out pattern.
When combined with hard metallic pads, these rotors can develop a harmonic vibration commonly known as the SRAM Turkey Warble.
This is one of the reasons SRAM introduced the thicker HS2 rotor platform, which adds mass and helps reduce resonance.
SRAM brakes are known for their excellent modulation.
Because they are easy to feather, riders often apply light braking pressure over extended periods during descents.
Unfortunately, sintered pads dislike prolonged low-pressure braking.
Instead of reaching the temperatures required for proper friction transfer, the pad surface can become polished and unstable, increasing the likelihood of vibration and noise.
Four-piston calipers rely on all pistons moving evenly.
If one piston becomes sticky due to dirt, dried brake dust or seal friction, the rotor can be pushed sideways into the opposite pad.
Organic pads often absorb this inconsistency.
Sintered pads do not.
The result is immediate vibration and noise.
Before fitting sintered pads, inspect your brake rotors carefully.
Many entry-level rotors are marked:
If a rotor is designed only for resin pads, it should not be used with sintered compounds.
These rotors are often manufactured from softer steel and may not be heat treated for metallic pad use.
Running sintered pads on a resin-only rotor can cause:
If your rotor says "Resin Only", either continue using organic pads or upgrade the rotor.
If your rotor is compatible with sintered pads, follow this process before blaming the brake pads.
You must remove the old transfer layer.
This helps ensure all pistons move uniformly.
Sintered pads have very little tolerance for poor alignment.
This creates an equal gap on both sides of the rotor.
The final step is often the most important.
Sintered pads require heat to establish a new transfer layer.
Never stop and hold the brakes on when the system is extremely hot.
Doing so can leave an uneven deposit on the rotor surface, creating a permanent pulse or squeal.
When the pads have bedded correctly, braking power will increase dramatically and noise will often disappear.
Brake pads do not create noise on their own.
Noise is simply vibration.
When a brake system is properly aligned, properly bedded, properly bled and running freely moving pistons, all brake compounds can operate quietly.
Sintered pads are simply less forgiving of imperfections.
They don't create the problem.
They reveal it.
If you prefer a compound that delivers strong bite, excellent modulation and quiet performance straight out of the box, a semi-metallic compound may be a better choice.
Our Enduro Pro Semi-Metallic brake pads remain one of the most popular options for riders looking for a balance of power, durability and low-noise operation without the extra setup sensitivity of full sintered compounds.