Hi everyone. I am new here but not new to downhilling. Although it's been a while. I used to race back in highschool and college and have recently got back into it.

I have an 07 Gary King Fisher. My brake system is completely the Avid Elixir XO's except for the rotors which are 8" Hayes. Couldn't get rid of the turkey gobble with the Avid HS1's.

I take the bike out to the mountain once a week. It seems that no matter what I have done with the bike in the mean time, or what the conditions on the trails are, I will get a loud howl from the rear brake under hard braking on my first run. Sometimes it will only last for half the first run. Then every time out it will go quiet and remain that way for the entire rest of the day. It can do this after it sits a while at home too. I ride it in the driveway and in a few minutes the sound is gone.

I thought that maybe it was from washing it when I got home, but that doesn't seem to matter either. It's if it has sat for a while. Is this a heat issue? Do they just simply need to be warmed up?

Thanks for any advice!