The washers are a convex-concave pair.. made by the Many Millions and used on all V brake Brake shoes in pairs on either side of the brake arm..


The alignment using them on the Post mount bolts is super simple ... with the bolts a bit Loose You hold the brake lever , so the pads grip the rim.

and while still holding the brakes on You tighten the 2 bolts on the caliper.

on the V brake pad set there is a thicker and thinner concave faces washer that will offer a bit of radial adjustment when screwing into your adapter

of the size for the disc chosen.

same adapter functions with the next larger disc size on the front than the rear ..
and will usually be marked as such .

140/160; 160/180; 180/210 ..