Compact Chainsets

EasyDoesIt said:

Hi all

I'm thinking of putting a compact chainset on my bike but i was wondering could i just buy the 50 and 34 chainrings and fit them onto my existing chainset which has 53 and 39 rings on at the moment with 172.5 cranks. Oh it's Campag Centaur groupset i have. Also can i stick with my existing front derialeur, it's a braze on type and at the moment it's at the very top of the braze on clip, i.e. there's plenty of room to move it down for the smaller rings.

Thanks in advance

No, they have different bolt centre diameters. You will need the crankset.

Ok thanks, do u know if i need the derialeur too ?

You can probably use the existing front derailleur. Although Campagnolo does make a compact FD, the regular ones work acceptable with compact drive trains.

EasyDoesIt said:

I'm thinking of putting a compact chainset on my bike but i was wondering could i just buy the 50 and 34 chainrings and fit them onto my existing chainset which has 53 and 39 rings on at the moment with 172.5 cranks. Oh it's Campag Centaur groupset i have. Also can i stick with my existing front derialeur, it's a braze on type and at the moment it's at the very top of the braze on clip, i.e. there's plenty of room to move it down for the smaller rings.

For the time being, you could get a 28t (8-speed ... you'll probably have to notch it to fit the key in the freehub) OR 29t cog and re-stack your cassette to satisfy any immediate/pending need for slightly lower gearing.

While a rear derailleur with a longer cage would be preferable, you may be able to get by with what you have, or not ... depends on whether you remember NOT to use the largest cog with the large chainring OR (alternatively) if you are willing to have some chain slack hanging on the "return" in some combinations ...

If you have a really Campy "friendly" bike shop, they can change the rear derailleur cage ... but, it probably less expensive to simply buy a new, Veloce/Centaur "long(er)"-cage rear derailleur

Ok cool thanks for the replies, think i'll just splash out on a new chainset, seems to be the easiest way, thanks for all the help.

EasyDoesIt said:

I'm thinking of putting a compact chainset on my bike but i was wondering could i just buy the 50 and 34 chainrings and fit them onto my existing chainset which has 53 and 39 rings on at the moment with 172.5 cranks. Oh it's Campag Centaur groupset i have. Also can i stick with my existing front derialeur, it's a braze on type and at the moment it's at the very top of the braze on clip, i.e. there's plenty of room to move it down for the smaller rings.

You can buy a 50 tooth outer ring for Campy's 135mm bolt circle, but the smallest inner ring that will fit is a 39. With Shimano you can use a 38 inner ring.