The chain ring range a "braze on" front derailleur can accommodate is determined by where the frame manufacturer places the mount on the seat tube. I suspect most frames designed for road use would be able to accommodate a 52T ring, but the only way to be sure it to try it.

Personally, I'm not terribly fond of "braze on" front derailleurs for exactly that reason. The only place they make sense to me is with non-round seat tubes where a clamp can't hold the derailleur.