I have Shimano XT disc brakes on my Salsa and slowly after riding it for a couple of weeks the disc brakes started squealing. Have you ever ridden a bike which squeals when you brake? This is really annoying and the killer for any downhill!
I was really close to rip off the whole brake system and get Magura MT’s. But I thought I give the XTs a last chance and apply all the tips which I could find in the web plus some which I got from a local bike shop (thanks to Chris from http://www.roaringmousecycles.com/ in San Francisco). Long story short. After doing all the stuff below the brakes were deadly silent! Absolutely no noise, nothing!
If you are having problems with your disc brakes I really suggest to read what I did. Disclaimer: Be careful when you work on your bike! Always go to your local bike shop if you are uncertain about what you do or don’t have experience. Please understand that you are solely responsible for the work you do on your bike and that I will not take over any liabilities.
Besides the usual tools like allen keys, torx wrench (most likely your rotors are bolted down with torx screws) and grease you need
Disc Brake Pads
Get the right ones! Disc Brake Pads are not all the same and some of them can be the main reason why you brakes squeal. I have the stock Shimano XT disc brakes on my Salsa El Mariacchi. Although the brakes are great in general the standard brake pads are known for causing a lot of noise. The material (a kind of a steel mix) lasts very long but can make crazy noise.
The ones you want to have are so called ‘Resin’ brake pads. These pads are made up of fibers and organic material that are bonded together with resin. You can find more details about the different kind of pads over at Pinkbike.com.
Clean your brakes before you use the new brake pads! This is essential. You need to get rid of the grit of the old pads as well as other dirt. Otherwise you will ruin your new pads.
Use a clean cotton cloth, put some alcohol on it and carefully clean the pistons.
Take off your rotors and use the sand paper to get rid of all the dirt. Then clean them with alcohol and make sure that you don’t touch the outer ring with your fingers afterwards. Put some grease on the side of the rotor which will be mounted against the hub. Do not put grease on the screws! Instead use locetite to make sure your screws stay in place even with heavy braking.
Mounting the pads
Apply some grease on the back side of the pads. The side which goes towards the pistons. Make sure it’s only a very thin layer and that you don’t put any grease on the break side!
Bent the clamp outwards. This adds a little bit more pressure to the pads and presses them a bit more against the pistons. This makes sure that the pads go back after breaking and don’t slide against the rotors.
Before the first ride
That’s it! Now your brakes should be dead silent. Before you do the first ride make sure that you break them in: Speed up to 25-30mph, go back over your saddle and break as strong as you can. Do this 4-5 times. The rotors and pads will get hot and cold very fast. This is what you want. You don’t want to get them hot for a longer time by for example riding down a longer hill and break slightly all the way down. This will cause glace on your new pads and will ruin them!
Now, go out riding! Enjoy.