I fear this is a stupefyingly simple question, but would my regular 53/39 road setup become 'compact' by merely swapping the chainrings out, or is there more to it than that?
Never felt as though I've needed to change anything with it before, but I'm planning some riding in the Alps this summer and have been giving a compact chainset some thought.
Cheers!
you will need to change cranks. Compact PCD is 110mm whereas you will have 133 or 135 PCD cranks for a regular set up.
I looked into this and ss far as I know the PCD's on the rings are different. You'll need to buy a new Chainset. I could be wrong though.
Edit, Beat me by 7 seconds. 
No, the bolt circle diamter on the cranks is different from a standard road to a compact
Campag road (53/39) BCD is 135mm
Shimano Ros (53/39) BCD is 130mm
Compact road BCD is 110mm
on a standard Road chaniste you cannot go as small as 50/34 chanirings as there would not be enough room for bolt holes (if you follow what I mean)
From a compact chainset however you can go to 52/38 (and maybe a bit higher - I think Carlos Sastre for example uses a 54T big ring for TT's on a compact chainset)
NO, BCD is different - you'll (probably) have difficulty getting a smaller chainring than a 39 with your current set up.
Your chainset almost certainly has larger fixing centres than a compact i.e 130 as opposed tp 110, so no I doubt you can just swap.
Flippin eck some quick draw boys there.
Baws, I knew there'd be something! Ah well.
A 130 Bolt Circle Diameter (BCD) on regular 53/39 chainset will make it impossible to run anything smaller than a 38 on the inside. So you can run 50/38 but that wont give you the low gears you want. To go 50/34 or 50/36 you would need a crankset with a BCD of 110.
I'd advise a compact with an 11/26 on the back for the Alps. Perhaps even an 11/28 depending on how strong your legs are.
I used a 50/34 with 13/29 for riding la Marmotte. It meant I could stay in the saddle for much more of the climbs than some of the painful looking big gear churners.
aP - Campag huh? I don't think shimano comes in 29 
Anyway, its good advice. After 160kms and three cols in your legs having a 29 at the back would be a godsend. I rode it with a 26 and it hurt...still got a gold time though 
hehe - did too much work on the valley road to the foot of the Telegraph which cost me dearly on the A d'H
By a compact chainset, use it, then sell it here SH - probably cheaper than changing rings. Some deals around too.
Also, you may decide you don't want to go back.
Ap - as early as that. Nasty with Telegraph, Galibier and ADH to go? The trick to a good time is to do NO work on the front at all if you can avoid it. Sounds mean spirited but no one will thank you for being their lead out man for 150km and then blowing. I sat in and was feeling good for ADH but a broken pedal spindle all but wrecked my time. Want to go sub 8hrs this year.
There's always Sram Apex:
http://road.cc/content/news/14605-sram-launch-new-apex-groupset
I went through this when I moved to the lakes. Ended up keeping my 'traditional' 53-39 front set up and going MTB cassette and derailleur on the back, as it worked out cheaper. Works fine, gets me up honister etc. Big gear spacings a bit of a pain, seem to spend a lot of time shifting between front cogs to get it just right.
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