Chainring sizes for Campag record chainsets
I have a 10 speed square taper Campag Record chainset with 52/42 chainrings & am struggling with the 42 ring, even with a 13-26 cassette (I live in South Wales). What is the smallest inner-ring I can fit to this chainset? I have a spare 39 tooth ring but can I go lower? Am considering a compact but would prefer to avoid the expense.