Originally Posted by Wilfred Laurier

Some might but the vast majority will absolutely not. Only if the fork has pivot placement such that the pads are adjusted all the way in one direction, which most do not. The transition from 27" to 700C is only 4mm, but around half of the conversions I have seen attempted were not a simple conversion due to lack of brake adjustment. Also, the conversion from 26" to 650B is 12.5mm of pad adjustment away from the brake pivot, so the stopping power will be greatly decreased for given hand force at the lever.