Thanks gpshead for sharing your experience with converting to 180 mm. Your 180 mm rotor seems to have a particularly narrow braking surface. Is it a "road" rotor? I just went ahead and did the conversion myself, using a Shimano RT-54 rotor and a Shimano 160-180mm post-post adapter. Mine seems to line up well (though I haven't taken it for a real ride yet). The RT-54 is a classic "mountain bike" rotor, and it's not surprising that the braking surface matches with the TRP calipers because the brake pads are interchangeable with the Shimano B01S (and similar) pads.