Originally Posted by
seypat
What rccardr said.
In my experience, you can have only so much spread between the 2 outer rings. The middle tooth count doesn't really matter. If you're going to run a 52 big ring, about 30 is the smallest you should go on the granny. So a 28 granny would mean a drop to a 50. Smaller than 28 means you'll need to run a big ring smaller than a 50.
Seypat, using your examples, are you saying that there should only be a 22 teeth difference between outer and inner rings? I'm going with a 50 and 28, so that's in that range. However, looking at what rccardr uses, 48/36/24, there is a 24 teeth difference. I am probably misunderstanding you, and I'm sure there are many variables involved between derailleurs, etc. You also state the middle tooth count doesn't matter. That is what I was thinking, but others have suggested my idea of using a 34 middle with a 28 inner won't work very well. As a result, I was leaning toward going with a 36. I've looked at a gear chart and think I will be okay since I will now have the 28 inner. I guess it will just be a matter of how well things will shift. It seems like there are more things to think about than I planned, which is why I am glad I asked. Everyone's advice has been helpful and certainly saved me some money in failed attempts!