Originally Posted by
mikemowbz
Looking around since, I've discovered that very few other derailleurs have this design feature - unsuitable for this bike, fine on many others.
So, I try another. Question was: which? Answer: probably lots of good options out there.
The fact that you're willing to mix-and-match on this bike opens up a lot of options, too. I was going to offer you my NOS braze-on RX100 FD (for cheap), but I just double-checked and it has that diagonal geometry! Rats, I'm never gonna sell that stupid thing.
My vote would be for DA (I can't find any diagonal ones on VeloBase, so you might be safe with any) or 6401 Tricolor (not 6400).
Oh, and a further tip -- with a regular FD, you might find that the cable anchor bolt is the next thing to possibly contact the tire. I solved that issue on a previous setup by substituting a different bolt with a much lower-profile head.