25 to 26 on rear question.

[norcalbiker]

Hello you all,

I have a campy compact double with 12/25 on the rear. I am thinking of getting another rear of wheel (same exact model) to put a 13/26 so when I need to climb I can just switch the rear wheel. I know that this is not much of a change but I think it would help. I really don't want to go 13/29. So before I purchase a rear wheel and a cassette, let me ask some expert here.

Do I need a longer chain?
Is this an easy swap?
Do I need to make any kind of adjustment every time I swap rear wheel?

TIA you all.

[Dave]

You have to ask if it's easy to swap a wheel? If you can change a flat tire, you can swap wheels.

There's always the chance that a small change in shift cable tension might be needed between the two wheels.

You don't need a longer chain.

The change would be a waste of money. Most people get a 13-26 because they want the 18T cog in the middle and are willing to give up some top gearing.

You could try making a 12-26, by using the 23-26 from a 13-26 with the rest of the cogs from the 12-25. I've never tried this, but I'll bet someone posting here has. The problem that might occur is a poor shift at the 21-23 due to a difference in the two cog's radial timing. The cogs are are positioned to insure optimum shifting.

[BCS]

I have a campy compact double with med cage rear der. I switch btw 12-25 and 13-29 frequently. The chain length is fine and no adjustments to anything are necessary. ATMO, not enough difference btw 25 and 26 to matter.

[Dave]

I have a campy compact double with med cage rear der. I switch btw 12-25 and 13-29 frequently. The chain length is fine and no adjustments to anything are necessary. ATMO, not enough difference btw 25 and 26 to matter.

That's OK with a medium cage RD because it has the wrap capacity to handle the 13-29. The chain length can be set for the 13-29 and either the big/big or little/little methods will suggest the same suggested length. There is never a need to shorten a chain when it's at the length that provides maximum wrap capacity.

Using a short cage is more risky. Some chainstay lengths produce up to 2T more wrap, so some people can wrap the big/big and the small/small while others can't. Some people just use the same maximum chain length for the short cage RD, knowing that they will never accidentally shift to the big/big.

[ridethecliche]

Honestly, I think it's a waste of time to swap to the 13-26 cassette.

Go to the 13-29 or stay with the 12-25. The difference isn't worth it.

Also, why don't you just swap cassettes instead of swapping wheels?

Much cheaper and not a pain...

[sjbraun]

I agree with those who say you'll find little (if any,) benefit by switching to a 12-26. I break out a 13-29 once a year just for the Moab Century Tour. (Its next week and I can't wait.)
I use a Chorus short cage RD, I don't need to change anything when going to the 13-29.

I do have to be careful to not shift into the 50x29 combination.

Once the Moab ride is over, I'll switch out the cassette to a 11-25. I spin out too easily on long descents in the 12-25 with a 50x34 compact.

Steve

[Tobias]

Do I need a longer chain?
Highly unlikely, but possible if your present chain is at maxium in the 50-25 and can't take any more capacity at all. It is very doubtful that's the case, but worth checking. In any case the most you'd need is a new chain of the correct length the first time; after that it would be OK.

As others have said, changing from 25 to 26 (only 4 percent) isn't much. I wouldn't go to the cost of a new wheel and cassette for such a small difference.

[norcalbiker]

Thanks you all!!!

Decided not to do it at all.

[Tobias]

Thanks you all!!!

Decided not to do it at all.
This is a good example of why I like triples.....the flexibility to make changes is far greater than that of compacts or typical doubles.

[djg]

I dunno -- an extra gear is an extra gear, and you want it or you don't, and it's way easier to swap wheels than cassettes. Changing out a 12-25 wheel for a 13-26 should take all of 30 seconds and, unless you've really got things set up at the margin, should go just fine if you pop out one wheel and pop in another. I've changed to a 13-29 for a climbing trip and had it work fine (of the last two times, one time I needed to futz with the rd a bit, the other time I didn't).

[RPS]

I dunno -- an extra gear is an extra gear, and you want it or you don't, and it's way easier to swap wheels than cassettes.
You're correct; however, I happen to agree with most recommendations above -- the difference between a 25 and 26 cog is not enough to warrant buying a new wheel just to make the change back-and-forth.

Having a backup wheel can be a good thing, and having a large cassette can also be a good thing, however, replacing a 25 with a 26 doesn't accomplish much; and that was the question. If he wants to consider a 29 (or even a 27 or 28) that's a different issue.

[salvatore]

I borrowed a friend's 13-29 this past weekend for the Everest Challenge and ran it on the second stage (should've used it both days!). Needless to say, it worked very well... so well, in fact, I decided to leave it on for my recovery ride today. Got me thinking I would like to have two set-ups: 11-25 and 12-29.

What would be the best way to make a 12-29? I've heard people say the "timing" can be thrown off by matching different cogs off different clusters, but if they are all Campagnolo, shouldn't it work just fine as long as you use the proper spacers? I have an 11-25 and a like-new outside 12... couldn't I just take off the 11, replace the 12 with the outside 12, remove the 25, add a 26/29 pair?

Thanks!

[djg]

You're correct; however, I happen to agree with most recommendations above -- the difference between a 25 and 26 cog is not enough to warrant buying a new wheel just to make the change back-and-forth.

Having a backup wheel can be a good thing, and having a large cassette can also be a good thing, however, replacing a 25 with a 26 doesn't accomplish much; and that was the question. If he wants to consider a 29 (or even a 27 or 28) that's a different issue.

Fair enough. I do agree that the 25/26 difference is not huge and that if one wants a true climbing wheel as a significant alternative to the all-rounder, it probably makes sense to go with a bigger cog (and bigger difference) than the 26. I keep a 13-29 record 10 cassette around for just that reason. OTOH, many of us have backup wheels (and backups of the backups) and if the backup is pretty similar, but a little different, well . . . that's another way to juggle expected costs and benefits.

[Pete Serotta]

if I can not get up an incline on a 25, I can pretty much guarantee a 26 will not get me up it either. I have tried a 25 and 26 at times locally and I did not notice a plus nor a minus of one verses the other - but then they only thing I race for is the RED that MARK pours.... :beer: :help:

(only caveat is that over a 10 mile climb say in the rockies a one tooth might help - but then I would want a 27 (shimano) or a 29 is campy 10 speed)

[RPS]

Fair enough. I do agree that the 25/26 difference is not huge and that if one wants a true climbing wheel as a significant alternative to the all-rounder, it probably makes sense to go with a bigger cog (and bigger difference) than the 26. I keep a 13-29 record 10 cassette around for just that reason. OTOH, many of us have backup wheels (and backups of the backups) and if the backup is pretty similar, but a little different, well . . . that's another way to juggle expected costs and benefits.
As I stated in the other thread that is very similar to this one, when a rider is already using a cassette that is in the upper range of size and is looking for significantly lower gearing for climbing, it makes sense to me to also look at the chainrings to ensure it would not be better to switch to smaller rings.

Personally I can’t see myself ever using a 13-29 cassette on a bike but understand others wanting to. Given that need I’d go with an 11-25 and use proportionally smaller rings. In this case the OP's 25 is in the middle of the typical cassette range and therefore he has more options.


P.S. -- Agree we can't have too many backups.

[r_mutt]

I borrowed a friend's 13-29 this past weekend for the Everest Challenge and ran it on the second stage (should've used it both days!). Needless to say, it worked very well... so well, in fact, I decided to leave it on for my recovery ride today. Got me thinking I would like to have two set-ups: 11-25 and 12-29.

What would be the best way to make a 12-29? I've heard people say the "timing" can be thrown off by matching different cogs off different clusters, but if they are all Campagnolo, shouldn't it work just fine as long as you use the proper spacers? I have an 11-25 and a like-new outside 12... couldn't I just take off the 11, replace the 12 with the outside 12, remove the 25, add a 26/29 pair?

Thanks!


can someone please explain the difference in shifting between the "A cogs" and the "C cogs"? i've read elsewhere that the timing will be off if you mix the 2.

here is the campy catalogue for a listing of cassettes and their proper cogs.

See pages 76-82 of the linked PDF.

http://www.campagnolo.com/repository/documenti/en/Spares08_B_1007.pdf


:)

[jeffg]

Personally I can’t see myself ever using a 13-29 cassette on a bike but understand others wanting to. Given that need I’d go with an 11-25 and use proportionally smaller rings. In this case the OP's 25 is in the middle of the typical cassette range and therefore he has more options.


P.S. -- Agree we can't have too many backups.

13-29 is a good option for very hilly circuits and very long rides (I don't worry about spinning out on descents on double centuries, but many of them a very technical as well so it's not an issue).

I do prefer the 11-25 for most riding, but I just left the 13-29 on my one bike and really don't miss the 11-12 except on a few descents