This is pretty much a selfish article. Whenever I come to buying new brake pads for my bike, I always forget the different compound types and what they are best used for. So, this is really a reference for me to keep coming back to, and who knows it maybe useful for someone out there to refer to as well.

Compound Types

You can’t visually tell what compound a pad is, unless you’re a real pad geek, so you’ll need to confirm the type from the product description or packaging.

There are two ends on the brake pad spectrum creating the type of brake pads. Resin brake pads, also called organic, are composed of organic materials like glass, rubber, and fibrous binders bonded together with resin. At the other end of the scale are sintered brake pads, also known as metallic, which are made of metallic grains that are bonded together at high pressure. The third type are a mixture of the two known as semi-metallic.

All pads are made by mixing various powdered additives with a binding agent and then squashing it all together at high heat and pressure to form a solid block on the backing pad. What's in the mix of powders has a drastic effect on what the pad's properties will be, giving us the three main types of disc brake pad compound for bikes.

Some manufacturers confuse things by using new buzzwords or sound-alike terminology. Remember there are three fundamental compound types: sintered, organic and semi-metal. Sintered pads are sometimes called “metal” or “metallic”. Organic pads are sometimes called “resin”.

Organic

Also commonly known as resin pads, these are the usual fitment on most new bikes. They're made from non-metallic additives such as rubber, glass, carbon and Kevlar to provide an all-around pad that works for most people but isn't very durable under hard use.

Pros

• Excellent initial bite from cold
• Less noisy. Very little braking noise.
• Slow rotor wear
• Quick to bed in.
• They don’t pass as much heat into mineral oil systems.

Cons

• Friction falls off quickly at very high pad temperatures
• Pads wear quickly
• Not as long lasting as sintered, especially in wet conditions.
• Less power at the ultimate top-end power (i.e. sustained high speed DH stuff).
• Can glaze over.

Sintered

Also known as metallic brake pads, these use a very high proportion of metallic fillers such as copper, steel and iron. They're made for work best under extreme use condition, so often aren't the best choice for general riding.

Pros

• Strong, effective braking at high pad temperatures
• The pad material can withstand very high temperatures.
• Slow wear rate even in poor conditions
• They last the longest.
• They don’t glaze over.
• They have lots of power at the ultimate top-end power (sustained high speed DH stuff).

Cons

• Can be noisy
• Poor bite when cold - need to be hot to work well
• Metallic content can transfer more heat into the calliper, potentially overheating fluid. This can cause mineral oil systems to fade on very long sustained descents.
• Faster rotor wear
• They take ages to bed in.

Semi-metallic

As the name suggests, these have metallic fillers mixed with organic fillers to give a balance of the qualities of each. They're a bit of a Goldilocks option, so they're good for anyone that wants increased hard-use performance over an organic pad without the drawbacks of a sintered pad. On the flipside, they retain some of the drawbacks of each, too.

Pros

• Better high-temperature performance than organic pads
• Less noisy than sintered pads
• Decent bite from cold
• Most of the best bits of sintered and organic compounds. They’re basically organic pads with sintered stuff added to them.
• Good ultimate top-end power.
• Good durability.

Cons

• Composition - and performance - can vary wildly from brand to brand
• Don't have the same ultimate high-temperature performance as sintered pads
• Noisier than organic pads
• Can glaze over.
• Not all semi-metal compounds are the same ie. different brands will have different sintered-to-organic mix ratios.
• Usually a bit more expensive.

Which type should you buy?

It depends. As with many things in life, it really comes down to what sort of riding you do and where you'll willing to compromise.

If you live somewhere flatter or just don't throw yourself down huge descents all that often, there's nothing wrong with an organic pad. It'll give strong braking from the moment you pull the lever, they're quiet and often cheaper than the other options too.

If you regularly ride long, sustained descents with a whole load of braking or ride somewhere gritty and wet and wear out pads regularly then sintered are a smart choice. If you don't mind the noise, they're powerful and have plenty of bite once they're warm and last for a long time. For example, are you going to the Alps? This is when it might be a good idea to run a sintered pad at least in your front brake – or at least pack one in your kit bag in case your organic pads can’t handle the sustained onslaught.

One thing to mention is you don’t have to run the same pad compound in both your brakes. A lot of experienced MTB riders run a sintered pad in the rear brake and an organic or semi-metalic pad up front to offer a good blend of performance - or even semi-metallic at the rear and organic at the front. The rear brake requires less power and feel so it makes sense to prioritise durability. The rear caliper also seems to get more filth flung through it so a harder-wearing sintered pad makes sense. The organic pad in the front brake offers good power and feel, where it is needed most. The trade-off in durability is well worth for most riders. Don’t forget as tempting as sintered pads are, due to their durability, the reality is that they lack power up front and take far too long to bed in.

If you want an easy life and only want to buy (and carry) one sort of pad, then go for semi-metal pads. Semi-metallic pads are an excellent compromise, with decent bite from cold, respectable high-temperature performance and good wear characteristics.

NOTE: I’ve heard the term ‘De-glazing’ pads. Before buying new pads check your pads have actually run out of pad material. Sometimes they may just be glazed over and feeling like a spent pad. Glazed pads can be brought back to life with a bit of sandpaper or light filing.

Styles

Different brake calipers have different shapes and different methods of holding the pads in place. So, when it comes to replacing your disc brake pads, the first thing you need to do is make sure you get the correct fitment for your brakes. There are loads of different styles available, so don't think that all Shimano or SRAM brakes will use the same pad, they don't. For example, there are numerous different pads for Shimano XT brakes, depending on which year they were made.

If you know the exact model and year of your brakes, then this is a good starting point, but the best way to know if new ones will fit to remove the old ones and visually compare them, you're going to have to do this anyway if they're worn out, so it's no great hardship. Thankfully getting the correct shaped pad is obvious.

Alternatively look at what your brake is called, it’s usually written on the lever reservoir and/or the caliper body or find the specification list on the internet for your bike to confirm what brakes were fitted. Then find a disc pad of the same name. If the model names don’t quite match or are incomplete, revert back to taking your existing pads out and double-checking they are the same shape as the potential replacement pads.

Check out some of my other articles:

Be Free Be Happy - Mountain Biking the Felly

Into the Woods

The Summer Starts

Biking in 2018

Sunday Dusk

Special Morning

Snow day

Summer is Back