Hi
I found that i had a crappy brake When using a Trial tech sl 19",
Using TNN LGM's or Belaey and i know that is wasn't the pads as i was using the Belaey on an echo urban rim before, And they where working amazing as they do,
So i got a echo tr rim and they where working mint on that to so yeah i found that it was the rim, Pads just don't like it
Only other thing maybe try a 2 bolt booster and put the booster on top of the clamps using smaller blots like in the pics
Hope this helps
Jamie