Originally Posted by
clasher
I could live with 42 in the middle and that'd leave my 52 for the occasional overdrive gear or two and I'd have enough on the low end just using a 28 tooth inner ring. It turns out on both the stronglights I have the 52 rings are basically toast anyway so I'd happily run a 42-28 compact double and eventually snag another 52 ring off ebay or something... 'course there will be derailleur issues to sort out too. Anyway this is an exciting thread now!
I was going to say that I didn't think you could run the granny gear of a triple as half of a compact double, but I guess you can if you use some kind of a "bash guard" instead of an outer chainring. Not sure how you'd find one in 122 BCD. Maybe you could grind/machine the teeth off a 52-tooth chainring? They seem to be abundant and pretty cheap.