Originally Posted by
edthesped
Understood, but the Tiagra 4503 is widely reported to work with mountain triples. I fall in the it doesn't work category.
Bare in mind that 48t and 46t would be considered mountain bike big-rings. Going all the way down to 44t, you are really pushing a road derailleur to the limit. Not saying that it can't work but when you are on the fringes of a component's design, slight differences in seat post angles and chainstay length will start to matter. If you want a second opinion, we can meet up sometime, I'm in Pgh frequently enough.
I doubt that the 2 tooth difference on the IRD would matter.