The brakes on your bicycle go unnoticed most of the time. Until they stop working so well, that is. One of the common causes of poor brake performance is worn out brake pads. Here’s everything you need to know about replacing and upgrading your disc brake pads.
How long will my brake pads last?
How long you can expect brake pads to last is like asking how long a piece of string is. Different compounds impact the durability of a brake pad. Then there is the type of riding, the terrain, the weather conditions, the rider weight, these are factors that influence how long the brake pads last. Generally, you can expect disc brake pads to last longer than rim brake blocks, part of the reason they have become popular in the UK.
When to replace brake pads
If you ride frequently, it’s a sensible idea to visually inspect your brakes on a regular basis. While brake pads can last a very long time, the last thing you want is to get caught out miles away from home with ineffective brake pads because you’ve let them wear down dangerously. Brake pads will wear more quickly in the winter so it’s critical to pay them close attention at this time of year.
If your brakes don’t feel as good as they did when the bike was new, it might be a sign you need some new brakes. With mechanical (cable operated) disc brakes, you can start to tell when your brake pads are wearing down as the brake lever will pull closer to the handlebar. To remedy this, you can take out the slack in the system by using the barrel adjuster on the lever or caliper to adjust the cable tension. Hydraulic systems automatically adjust the pad clearance.
It’s a little tricky to do a quick visual inspection of disc brake pads. While you can peer closely at the caliper and see how much pad material is remaining on the metal backing plate, sometimes it’s easier to remove the wheel and inspect the brake pads without the disc rotor inserted between the pads.
There should be a reasonable amount of pad material on the metal back plate, a couple of millimetres at least, any less than that and it's a good time to replace them. If all you can see is the backing plate, you need some new pads!
If you do wear down your brake pads to the metal backing plate, you’ll likely know since they’ll make an awful sound and the performance will be poor. This is the reason for the frequent inspections, to replace the pads before they get dangerously low.
What brake pad choices are there?
Disc brake pads typically come in three flavours; sintered, organic and semi-metallic.
Sintered pads are made from hardened metallic ingredients and provide a long lifespan and good performance in the wet. They do take a bit longer to bed-in however, and they can sometimes be a bit noisy, but they cope with high temperatures well and are a good choice if doing some long descents, such as riding in the mountains.
Organic (or resin or non-metallic pads) pads are made from organic materials and bound together using resin. The material is soft so the bed-in period is much shorter, and that means they have more initial bite and they’re quieter. They don’t last as long as sintered pads, and they’re not great in wet conditions, and can glaze at higher temperatures.
The third option is semi-metallic. These combine metal and organic materials using resins to hold everything together with a steel or aluminium backing plate. They strive to provide performance that is somewhere between sintered and organic, but it depends on how much metal the manufacturer adds to the compound.
If you were to choose between these different pads, you would put sintered pads on for the winter, and organic for the summer, but many cyclists use sintered year-round quite happily.
Some manufacturers offer disc brake pads that attempt to reduce the heat buildup in a disc caliper. Koolstop produces a disc pad with a ceramic barrier between the organic material and the steel backing plate, to limit the heat that is transferred to the brake caliper.
Shimano produces Ice-Tech disc pads with feature cooling fins that operate like a heat sink, drawing heat away from the pads.
Often the best route is to replace like-for-like. Each manufacturer will provide recommended pads, and that's typically the sensible choice. Look at any online retailer and you'll see a huge choice of pads at different price points, each offering different benefits, so it can be worth shopping around if you want to try something different.
Not all brake pads are the same though, they come in a bewildering range of shapes. You need to ensure you buy new brake pads that are compatible with your brakes.
Replacing disc brake pads
Fitting new disc brake pads can be a little tricky the first time you do it, but once you know how, it’s a doddle. You can sometimes replace the pads without removing the wheel, but it’s easier if you first remove the wheel. Use a workstand if you have one, otherwise carefully pop the bike against the wall on some cardboard or carpet to protect the bike/kitchen floor.
Most disc brakes have a retaining pin that is threaded through the top of the brake pads, often with a retaining circlip at one end. First carefully remove the clip and pin and put them somewhere safe. Now, extract the worn out brake pads and dispose of.
Next, and this is the trickiest part of the job, the pistons need to be pushed back into the caliper body. Most disc brakes, certainly all hydraulic systems, are self-adjusting. This involves the pistons automatically pushing out of the caliper body to keep the correct pad clearance as they wear down. Mechanical systems, however, work similarly to a caliper rim brake and the cable tension needs to be adjusted manually.
With the brake pads out, take a suitably sized spanner or flat head screwdriver, and very carefully push the pistons back into the caliper. It shouldn’t require too much force.
With the pistons back in the caliper, you can now fit the new brake pads, which is the reverse process of removing them. The new pads should slide in easily. Reinsert the retaining pin and clip, put the wheel back in, and cycle the brake lever a few times.
It can take a little while for disc brake pads to bed in, riding up and down the road and applying the brakes with some force is often enough to get them working well.
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.