campagnolo gears

jimycooper

hi
i have just brought a bianchi with centour and my easest gear is 23-50 and in hilly area.
my last bike had shimano so im not sure if i could just put replace the 23 with a 25 or would i have to get a whole new cassete ?

Slow Downcp

You sure it's 23-50 and not 23-34 (or similar)? 50 seems a little large for an inner chain ring.

jimycooper

very sorry got it wrong its 23-39
sorry

redddraggon

You could put a 13-29 cassette on, making your smallest gear 39-29 about the same as 34-25

jimycooper

but could i just thake the cassete of the wheel and swap the 23 for a bigger number

redddraggon

jimycooper wrote:

but could i just thake the cassete of the wheel and swap the 23 for a bigger number

Yes. a 12-25/11-25 or 13-26 would be easy with no messing about. A 13-29 might be possible, definitely possible if you have a medium mech, probably possible with a short cage mech.

C-S-B

reddragon, I think hes asking whether it wud be possible to replace only the 23, not the entire casette (?)

campagsarge

Not sure if you can only buy single gears for the cassette?

redddraggon

C-S-B wrote:

reddragon, I think hes asking whether it wud be possible to replace only the 23, not the entire casette (?)

Well you probably can swop the 23, but the jump between the ratios will be too big then, finding a single sprocket will be difficult also.

jimycooper

thanks guys i think i'll buy a new cassete

jimwin

You should buy the whole cassette. As an experiment, I tried to make up a 12-29 by missing out the 16 but the 15 and 17 rings are not compatible leading to the chain finding it difficult to engage the next ring. The cogs are specially shaped so you have to match the cogs - you can't just replace them willy-nilly.

Unlike Shimano, Campag try to keep the changes between cogs relatively small to minimise cadence change . Too big a change leads to a big change in cadence - bad news. A standard cassette (e.g 12~25) tries to keep close spaces throughout though a 'climbing' cassette (such as the 13~29) allows the top 2 rings to have larger spacing as a 'bail-out' capability.

- JimW

gkerr4

I have a bit of an oddball 13-25 cassette for sale if you fancy it - campag centaur 2008 - zero miles - it was bought as a 13-26 but the 13 fouled the frame so I bought a 12-25 and then swapped the 25 (on the 12-25) for the 26 (from the 13-26) to give me a 12-26 on the bike and a 13-25 in the box.

drop me a PM if you are interested and I'll let you know the full 10speed ratios.

jimwin

Useful tip - a 26 large ring is slightly more useful than a 25 IMO.

Couldn't do that on the old 9-speeds since Campag riveted the top few rings together. But if the rings are separate, It's a good move since a 26 has the same tooth alignment as a 25.

- JimW

jimwin

I just checked the Campag cassette data and you can't just swap rings from one block with another. For example, the 12~25 cassette is made up of:

12A, 13A, 14A, 15A, 16A, 17A, 19A, 21A, 23A+25A

and 13~26:

13A, 14A, 15A, 16A, 17A, 18C, 19C, 21C, 23C+26C

The letters after each ring count show the alignment and you shouldn't mix them up (i.e. type A with type C *except* at 18C) otherwise the changes clunk rather than glide. The 18C ring changes the ring rotations for the 19C ring upwards.

The 12~26 cassette will be:

12A, 13A, 14A, 15A, 16A, 17A, 19A, 21A, 23C+26C

resulting in an incorrect tooth offset between the 21A and 23C rings.

Nice try GKERR4 but not a good idea.

- JimW

gkerr4

well - i've done it - been riding it since march and it's fine....

it doesn't look out of place and it certainly doesn't 'clunk' during the changes - in fact it changes pretty sweet!

a_n_t

jimwin wrote:

Useful tip - a 26 large ring is slightly more useful than a 25 IMO.

no sh1t!

jimwin

Seems like practice is better than theory in this case.

Just to double-check - you said you swapped the 25 for the 26. On the Centaur, they are paired rings so can I assume you changed the 23+25 with the 23+26?

- JimW