Picture of How To Change The Rotors On Disk Brakes
My bike was recently tuned however it developed an irritating screech and lack of braking power, so we decided to change the disks and fix the problem. Changing the disks is vary easy all it requires is a torks T25 screwdriver, and preferably a torque wrench. If you don't have a torque wrench don't worry unless you are racing, screw tight will do. 

Step 1: Tools and Materials

Picture of Tools and Materials
This is an easy project that takes about 30min the only tools needed are:
torque t25 screwdriver 
torque wrench (optional) needs to go to 40-60in lbs

new disk 

Hey Zaphod - thanks for th ewriteup - I thought this was more involved! Do the rotors come in different sizes, or do I need to worry about matching the new rotor to existing?

Yes rotors do come in different sizes, they are measured in mm most are 160 with smaller and bigger sizes available. I would just use a ruler and measure the ones you have. also some of the bolt patterns (5 or 6) are different. of you take the one on your bike of and bring it to a bike shop you should be able to get a good match.
www.chainreactioncycles.com is a great way to order online, great customer service
Jonno0133 years ago
Great Instructable! This doesn't happen very often but if your brakes rub when wheel is spinning, loosen the brake callipers at the frame, spin the wheel, pull brake on, and keeping the brake held in, tighten the screws. This normally requires a 5mm allen key. Keep up the good work :)
Zaphod Beetlebrox (author)  Jonno0133 years ago
Thanks for your tips.
samsq13 years ago
Did you try changing the brake pads or cleaning the rotor before you swapped out the rotor? That could have been your problem.
Zaphod Beetlebrox (author)  samsq13 years ago
Had new pads, used automotive brake cleaner too. Taken it to a mechanic, he couldn't figure out the noise either. We have contacted shimmano to resolve the problem.