Hello,

I had the opportunity of riding a brand new Brompton, and noticed its brakes worked a lot smoother than those on my 2014 Brompton, which uses the same dual pivot brake calipers.

Wondering if it'd do anything, I dissassembled the front brake to add a bit of grease to the central + right-side screws… but it doesn't seem to do much. It might be the cable + housing (which I changed a couple of years ago) or the brake lever.

But anyway, it got me wondering:
1. How does a dual pivot brake caliper actually work?

When pulling the lever, it pulls the left-side arm toward the rim as shown in 1 (and thanks to the spring, it returns to its original position when releasing the brake lever), but what about the right-side arm? Does it move thanks to the pressure applied by the housing, as shown in 2?

2. As the brake pads wear out, I understand we're supposed to loosen the barrel adjuster next to the brake lever so as to push the housing towards the caliper just a fraction of a millimeter… but how does it work? If it pushes the right-side arm toward the rim thanks to the housing (as shown in 2), what about the left-side arm? How does this other guy move towards the rim?

Note: left/right as seen while sitting on the bike.

Thank you.