I am a road triple novice. I have an older bike with an avocet triple on it, but I admit to just keeping it on there for show...but I'm doing Ride the Rockies in June and am feeling the need for lower gearing. I got a campy triple, and out of the wrapper it has a 53/42/30 on it. I have a 53/39 set of rings that I can put on it to replace the 53/42 set...

Is this a bad idea? what are the pitfalls?

I think that having an extra big cog in the back (like a 34) and an RD to handle it, would be more useful to you than swapping the middle 42 for a 39...

Both my road bike triples are 50/38/28.

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yeah, I'd like to bag the 53 but don't see any options for this particular crankset (campy record triple).

I've got a Racing T triple that came 50/40/30. Sure there are no rings smaller than 53? Anyway, you would probably be okay with 53/39/30, with a modern triple FD. The only possible issue is the 53 forces the FD higher, so it's more work to shift the chain from the 30 to the 39. Do you have a long cage RD as well? I think most modern road triples are 50/39/30 because of chain wrap issues. The road triple RDs don't wrap as much chain as a MTB derailleur. Or maybe there's another reason I'm not aware of.

I have a medium cage campy rear. It looks like a pretty long cage to me. I'd just try this, but I'm waiting for the bottom bracket to show up (I foolishly thought that the LBS would have me covered there...)

I think I answered my own question. Back in the day, when these parts were the shiz, the clever engineers at Vicenza made two sets of chainrings, designed to work together. 53/39 was the standard road configuration, and 53/42/30 (or 32) was the triple. The 42 has ramps and pins to help get up from the little ring, and the 39 does not. So...oh, well. I rode a 42 for a long time before 39s were cool. I suppose I can deal with that. But the little chainring has no pins. I can change that out, right?

I use that standard Campy triple you have with a 13/29 cassette and a medium cage RD on most of my bikes. I do lots of big climbs followed by longish descents. It's a good combo as-is, and will most likely be just the thing for the trip you have planned. Campy does make a 53/40/30 triple - I have one on my Cinelli. But I don't think it's worth swapping out the middle ring if you already have a triple in-hand.

I also have an IRD 11/34 cassette on one of my bikes, but I'm hesitant to recommend it. The thing I don't like is that is goes from 28 to 34 on the last two cogs, so if you are struggling a little bit on the 28, your only two choices are to keep struggling or totally bail to the 34. Plus, you'll need a long cage RD.

I really don't think you have to fret with this - go the simple, factory route and just get a 13/29 cassette and be done with it. You'll have all the "normal" gears you're used to, and the low gears for when you're getting gassed or just want to take it easy. I think you'll find that you'll spend the majority of your ride on the 42 in front, just working up and down the cassette as needed. Makes life simple.

For me, a 39T middle ring seems to hit a sweet spot. On bikes with a 42T middle, I have to shift to the granny earlier on some tough climbs, while with a 39T I can hang on a little longer. True, not a huge difference, but on short steep inclines sometimes small differences are big.

I've run a 30T rear cog on a Campy medium cage RD as well without incident. Why does Campy call it a medium cage? To differentiate it from a MTB specific RD? For kicks, I measured the center-to-center distance between the pulley wheels on a Campy medium cage and a Shimano 105 GS, and they are both about 8cm.

Campy makes a bigger rear - the SGS (?) has about another inch of cage, looks like. I spent some time today taking that crank apart and putting it back together. I went spelunking in my "never use these again" drawer, and found a 74mm bcd 26 tooth Specialized granny cog (new and unused! I guess I've always been a hoarder.) I think that I could run a 12-25 rear cluster and, paired with that granny gear, I would almost have regular road bike gearing and a 1:1 low gear. I am guessing that I'll be able to use the biggest four rear cogs with the 26 tooth inner, so I could have the luxury of shifting a little bit on the climbs.

That's the plan. Come on, bottom bracket guy!

If you're goiung to use that 26t ring withth e standard 42t middle, you might have some shifting issues to deal with - that's a big jump, 16t all at once.