Oh -- and the disc brake caliper. The actuation arm length actually isn't probative here, at least to my knowledge. They also make calipers compatible with short pull levers ("road calipers"), and they have the same actuation arm length as "mountain calipers." They differ in the shape of the ramped cam inside the caliper. The "road calipers" have a much steeper ramp to the cam and move the pads much more quickly than "mountain calipers" do. As such, the actuation arm doesn't rotate back as far to its free position.