All cheaper steel frames come with flat mounts. Genesis, brother, surly, etc. I guess it's cheaper to weld an IS mount to two tubes than to manufacture one with flat mounts.
I feel like I read something from either the fairlight or mason designer about how flat mount is a huge PITA compared to IS mount when you're dealing with the manufacturing of steel frames. because of tolerances etc
All cheaper steel frames come with flat mounts. Genesis, brother, surly, etc. I guess it's cheaper to weld an IS mount to two tubes than to manufacture one with flat mounts.