[Gavin2.6]

Mine have a flat edge. Should they be completly circular or should they have two flat sides. Googled a few fews pics and seems some do and some dont.
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[Merlinbadman]

There should be some method of stopping the pins from rotating in the barrel of the carrier. Be it flat edges that butt up to the edge of the caliper or have a "hexagonal" (I don't know many sides it has) collar to put a spanner on to.