Originally Posted by
del690
Thanks for info guys. I think if I ever do this I would have to diligently remember that big-big is off limits, even accidentally. I figured to get the chain sized comfortably on what would be a 48-36 front/rear combination (big-second big) and just make sure I was in the smaller ring when I went to the 42. Current setup on the bike is 48/34 up front with a 11x34 cassette, 10 speed. Rear dérailleur is a shimano R350, which I believe is med cage.
No, you have the wrong idea about this. You HAVE to make the big-big combination workable. It doesn't matter how much you try to avoid the combination, you will eventually shift into it. I had my bike setup exactly as you describe before, it was very, very annoying. Having to constantly worry about accidently overshifting and tearing off your derailleur. If you're going to do something like this, you'll need a long cage derailleur. That's what they're made for. (To take up lots of chain.) It doesn't make sense to set it up so that you can't shift into big big when the other way (can't shift into small-small) won't cause any damage whatsoever. (It'll just rub the chain and make lots of noise.)