Brakes not very good

When braking down from higher speeds with high pressure being applied on the brake pedal iv noticed my brakes aren't that good but at lower speeds they are perfect, can any one tell me why this is?
 
Brake pads probably seized into the caliper, this is a very common problem. Strip the calipers down and give them a good clean, then put pads back in with copper slip to stop it happening again.
 
You probably only notice it at high speeds as you require more braking force to stop in time. When they are sorted youll find it hard getting used to the dramatic braking improvement :lol:
 
Yeah definitely get them stripped down. Like Luke said, it takes you a while to get used to them again!