You know, I was thinking after posting that message that actually the only dimension that changes to move to a larger disc is the "height" of the mounts - i.e. to move the whole caliper radially outwards. In other words you might get by with some 10mm spacers between the caliper body and the tapped mounts on the upright. It would still be stiff in the directions that matter and in fact the greater bolt stretch might be no bad thing. Alternatively, I'm sure Marlin could make these mounts a few mm higher without much problem. Incidentally, the mounts appear to be for the 47mm top-hat disc, not the 45mm if that makes any difference to you. At least I hope I'm right because that's what I ordered
