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Discussion Starter · #1 · (Edited)
Campy Centaur Ultra Torque - cassette options

Hi All

I have a campy centaur full groupset ultra torque with "QS factor" :confused: (I can add pics tonight for identification) with a 11-25 rear and 39-53 front.

I need to switch to compact and I'd really like to just change out the chainrings but thus far I've read that compact rings won't fit.

Is anyone able to clarify this and suggest the best way to go about this? I'd prefer to keep the group as vanilla as possible...

TIA

View attachment 280511 View attachment 280512
 

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1. You have been told correctly that you can't put a ring smaller than 39 teeth on that crank. If you look at where the bolts are on your small ring, and imagine a smaller ring, it will be evident why this is so.

2. You could buy a Campagnolo compact crankset that fits your current bottom-bracket cups

3. You could buy a different brand of crank, with the appropriate bottom bracket parts to fit your frame.

4. You say you "need to switch." Do you really "need" it? What do you actually need? How much lower a low gear do you need? Could you get that in some simpler and cheaper way? For example, changing to a cassette with a 28-tooth cog would give you a low gear (with your 39 ring) almost the same (only 2% difference) as what you'd have with 34x25 with the compact.
 

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Compact cranks have a smaller (110mm) bolt circle diameter (BCD) than "regular" Campy cranks which are 135mm BCD.

The smallest small ring that will fit on the regular Campy crank is 39T. Just look at it.

You need to change out the crankset. The existing cups on the frame can stay. The front derailleur will need to be reinstalled in a lower position.

Unless you have the knowledge and tools to do this, I'd suggest a competent bike shop do it for you.

There is a much easier and cheaper alternative - change the cassette. Campy have a 13-29 Campagnolo 10 Spd Veloce Cassette, Cassettes, CASSETTES that will give you almost identical results for the bargain price of $44.
 

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Discussion Starter · #4 ·
Thanks.

What I "need" is much easier gearing, so changing the casette makes more sense. If going to a 12-28 or 13-29 will I need to get a new chain as well?

I will definitely have my LBS do the install; however I'd like to get the part myself.
 

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You may if the chain was shortened using the big/big method, although if you use two removable links and the LBS has some spare chain ends laying around that may work too... If you need much smaller gearing it might be wiser to move to a compact or even triple crank. Although the chain will definitely be long enough (it may need to be shortened) with a compact crank, if the chain is worn, you may want to get a new chain anyways to avoid premature wear of the new chainrings. The same applies if you get a new cassette.
 

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What I "need" is much easier gearing, so changing the casette makes more sense. If going to a 12-28 or 13-29 will I need to get a new chain as well?.
Likely a new rear derailleur as well...
I think you'd be happier just swapping out the crankset for a compact or a tripple. No need to stay with Campy (personally, I'd rather go with something more universal... even with the rest of the bicycle built up with Campy; but that's me).
 

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Make sure your current crank is ultratorque not powertorque. Campy changed centaur to powertorque recently.
 

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Not true. Campy short cage rear mechs have a 29 tooth large cog capacity.
I'm going by what Branford says...

Campagnolo officially recommends various rear derailleur cage lengths for use with specific cassette and double or triple chain ring combinations. However, it is important to understand that any 1999 to current, Campagnolo 10 speed rear derailleur, will shift up to a 29 tooth cog and down to an 11 tooth cog. The problem you will run into is that the derailleur cage may not be long enough to take up all the slack in the chain for a wide range.
 

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OP you first post said you had a PT crank. The ebay sale you linked to is an Ultratorque crank. Actually it is considered a much better designed system than PT. You will just need to change the BB cups as well to the UT type if you go this route.

There can be confusion about the issue of maximum cog size and RD capacity. They are two different issues.

Capacity refers to the RD's ability to take up chain as it moves from the big-big combo to the small-small. The RD's capacity is determined by the cage length. Campy short cage RD's have a max takeup of 30T, where this is the difference across the cassette plus the difference in chainrings. (this is based on experience rather than Campy guidance).

Thus with the 11-25 cassette you have now, the difference is 14T. And 53-39 chainrings have a difference of 14T also for a total of 28T. No problem for the RD.

If you change to a compact with 50-34, then that's a 16T difference, and added to the cassette's 14T gives 30T which maxes out the RD's capacity. (this is all in theory. in practice you could have a wider range, but some combo's of gearing approaching the small-small would not be useable).

The chain would have to be checked for correct length too, in making this change, as well as FD re-installation at the lower height.
 

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Discussion Starter · #12 ·
Hi All, thanks for your help so far. I've uploaded some pictures so that perhaps some of you will know my groupo and can suggest whether (and which model, please) of cassette I can change to. The debate seems to be whether I can get a 29 on there with my RD... I will go 28 if its going to be dicey.

Thanks again, and looking forward to easier pedaling. Cheers!
 

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OP you have an UltraTorque crank. I have the same in compact.

well if you believe headloss's Branford quote, then yes it will handle a 29 cog. don't see why not. pretty much all Campy 10-speed components ever made are compatible.

and the chain wrap will be 16T with a 13-29 plus 14T with your existing crankset, total 30T, so RD will be OK - WITH THE CORRECT CHAIN LENGTH. Suggest a new chain with a new cassette anyway.
 

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You will want a compact or CT front derailleur as well. They are cheap on ebay for campy. You will be able to work it without it, but it won't shift as nicely. If you can get away with your crank and a 13-29, I would as it will save you much money.
 

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You will want a compact or CT front derailleur as well. They are cheap on ebay for campy. You will be able to work it without it, but it won't shift as nicely.
I believe this only applies to the 2007 QS, then they changed the derailleur cage to CT + STD instead of having two different models. If the OP has a STD only model... then yeah, this is a serious concern and shifting will be the suck.

I personally went with a 2009/2010 Centaur FD for a recent build since it is the last year that Centaur came in silver but is more or less the same as the current Centaur and up design (while Veloce looks like the same design as the 2004-2007 stuff but with a newer cage). Price paid $50 after shipping. Newer models are identical but for color.

Actually, yeah... looking at the photo above the OP definitely has the 2007 version which isn't designed for a compact. You need a new front derailleur too! (if you change out the crank for a compact, that is) :(
 

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Discussion Starter · #17 ·
reporting back to say the 13-29 and new chain are working great. It's still not as easy as a compact setup but it will do.

had to remove 3 links from the new chain and the chain barely clears when wrapping it so I have to avoid doing that when riding!!! Thanks again for the guidance
 
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