Front wheel issue

[Kentish]

That all sounds good
But I still dont get it, because the pistons go in depending on how thick your pads are. So thicker pads wont be pressing on the disk any more than thin ones would.
isnt it ??

Pistons will only retract so far due to pressure in the system. they don't go all the way back. So if you were to put pads in and say slide a 1mm or 2mm thin piece of metal behind each pad it would push the pads closer to the disc and cause the wheel to bind. Remove the metal and you will have extra space hence the wheel being more free.