Normal for scraping new hydraulic mountain bike brakes?

Question

The hydraulic brakes on my new bike (Avid Juicy 7) rub the rotor to the point it can slow the front wheel without pressing the brake lever when the wheel is raised off the ground.

Is this normal break in?

Also, I have heard you have to condition hydraulic brakes so they don't "scream"... how do you do this properly?

Answer 1

one answer states doing hard stops...this may solve your problem but it is not the right way. what you need to do is take the wheel off take the caliper and rotate the pads out of it and push the pistons in...you can do this with a screwdriver but make sure the pads are out. Once this is all done, rotate the pads back in and make sure they snap into place. put the wheel on and make sure the quick release is tight so the rotor isnt loose or the pads will center wrong. flip the bike back over and slowly squeeze and pump the lever... your pads are set!

Answer 2

Rubs and screeching are usually the result of three things:  a tweaked rotor, improper mounting/alignment of the caliper or sometimes the mounting surface of the hub/rotor interface, and oil contamination.  It sounds like your caliper needs to be centered, but you should also spin the wheel and watch carefully to see if the rotor is true.

Before you check for any of that, be sure that your wheel is centered in the dropouts firmly and squarely so that you know that basic part is ok.  And remember that in hard corners you'll probably hear some zinging as the wheel and fork flex a bit causing the rotor to zing on the pads.  It shouldn't do that most of the time though.

You do need to burn in your new brakes for maximum bite once you're sure everything it set up properly.  To do that, bring the bike to several hard, fast complete stops on each caliper (individually).  A large hill or parking garage is great for this.  Do it 5 to 10 times for each caliper and you should notice progressively stronger braking each time.  Normal trail riding won't usually cut it.  What this does is embed brake pad material into the surface of the rotor, giving it a smooth shiny surface for the pads to mate with.  You might clean your rotor with some 91% alcohol before you do this, and every so often in the future just to keep airborne contaminants and car exhaust off of it.  

Hope this helps some....and enjoy the Juicy's when you get them proper.  They're excellent brakes!  

Answer 3

Most new pads need some break-in to operate well.  I don't know what Avid recommends, but, generally, you need to do several hard, fast stops.  Magura, for example, recommends 30 actuations of the brakes to break-in the pads.

With respect to rubbing, sounds like you probably have a centering issue.  First, make sure you have the wheel properly installed on the fork.  If the wheel is properly installed, you need to check the Avid manual for how to center the caliper.

Hope this helps.