I originally had it set up with a 50/47, the rings are steel, the rear is 16/18/20/22 and there was no problem with shifting between the rings, up or down on any of the rear gears.

I have some hilly rides planned and I want to switch to some alpine gearing. The new rings are aluminum, 48/45 and the rear is 17/20/24/28. It shifts fine from big to little but won't engage little to big.

I have gone up and down with the FD on the seat tube with no luck. There is a difference with the ring spacing. The aluminum rings are spaced about 6 mm c-c and the steel rings are about 5 mm c-c. My chain may be too short but there seems be enough play in the RD, I could be wrong though. Any ideas?

Here is a picture of the FD, if that is of any help.

Is the cage moving the chain over far enough for the outer ring to pick it up? It looks like the way that you currently have the height of the derailleur set the nose of the cage is doing most of the work...on my pile of reference junk the bottom edge of the inner cages show the most wear. That'd make me think that maybe that derailleur is not high enough above the rings. But, then again, I haven't messed with a lever-actuated derailleur, so maybe my reference material isn't old enough.

Could it be an angle thing? I have no experience with that type of FD, but with mine I found that when I made the FD exactly parallel to the chainline, it did not upshift from inner to outer ring so well. When I angled it very slightly toe-in, it started shifting a lot better.

Good luck and see you tomorrow, with or without this bike - hopefully with! Thanks for organizing tomorrow's ride.