Originally Posted by trailflow1

My point was the Shimano brakes are not the sole reason for any 'squishyness'. There are other possible causes.

Do you agree that any of the other things listed make a difference ? or are you going full denial ?

It's not difficult to understand. If you understand physics and forces you'll have an inkling what it means. Considering the pads/holders are the part of the brake that touches the wheel first and take the brunt of the forces. And they are smaller in size (and weaker) than the rest of the caliper. It makes sense that the interface between the pad holders and the calipers arms is secure as possible to minimise deflection and maximise braking efficiency.

In simple terms. If the pad holder bolts are loose. The pad holders will move,twist and shift under braking forces contributing to a spongy 'feeling'.

Display bikes in shops may or may not have been fully checked for tightness.

Like i say your ''testing'' methods are practically useless anyhow to gauge how Shimano brakes feel. Static brake feel is not the same as braking in motion as the brake is dealing with alot more forces,weight and momentum.

If you don't believe "pad holder bolt tightness". Loosen your bolts to the bare minimum and go for a ride.