Max Sprocket Size for Campag 10 Speed

For discussions about bikes and equipment.
Valbrona
Posts: 2291
Joined: 7 Feb 2011, 4:49pm

Max Sprocket Size for Campag 10 Speed

Postby Valbrona » 20 Jun 2012, 12:54am

Please note I am talking old style Campag 10 speed with the B screw on the cage rather than new style 10 speed with the B screw in the 'normal' place.

The largest sprocket Campag did was a 29 in their 13-29 cassette, but ignoring capacity of the rear mech, is it possible to go larger, say 30/32/34? I know MickF is using 30, but is there a point at which no matter how much adjustment of the B screw the cage of the rear mech hits the sprockets?

Thanks folks.
I should coco.

User avatar
Mick F
Spambuster
Posts: 49155
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Max Sprocket Size for Campag 10 Speed

Postby Mick F » 20 Jun 2012, 7:33am

No I'm not.
I'm 12-29 Miche Custom cassette with a Medium Cage Chorus rear mech like this one:
campag chorus r der 04.jpg
campag chorus r der 04.jpg (18.8 KiB) Viewed 4149 times

Campag state that 29t is max cog size, but for 2013 they are bringing out a 12-30 10sp cassette!

Since finding out that this new cassette is coming out, I've done some measuring and checking. I'm convinced that the 30t will fit, and also that my medium cage will cope with the extra tooth. Consequently, as soon as I can, I'll be buying one.

Whether a larger than 30t will be ok, I don't exactly know - perhaps 32t will just about be it though. Where I will come unstuck is that I'm running 53/42/30 at the front and my medium cage rear mech will be at it's limit when I get a 12-30 cassette. I do have the option of buying a long cage (as a spare part) for my Chorus mech. I could also make a longer cage if the cost is prohibitive. Either way, 12-30 will be ok and I doubt I'll ever need to change to a wider cassette. I am happy with 12-29 at the moment, but 12-30 would be even better.
Mick F. Cornwall

Brucey
Posts: 39316
Joined: 4 Jan 2012, 6:25pm

Re: Max Sprocket Size for Campag 10 Speed

Postby Brucey » 20 Jun 2012, 7:43am

If you run out of adjustment, it is normally possible to diassemble the upper 'B' pivot and alter the preload on that spring, in some cases by drilling an extra hole for one end of the spring. Similarly the lower pivot spring can be modified/adjusted too. However some folk have found it difficult to disassemble these pivots, so this approach is not for everyone. I don't know how much capacity increase can be had via this route; it may well vary with exact mech model.

In any event it rather depends on how long your gear hanger is; this can add a couple of teeth to the mech capacity quite easily.

Normally it will come down to a 'suck it and see' exercise. If in doubt you could always throw a shimano wheel in with a 30 or 32 on and see if it works or not.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
CREPELLO
Posts: 5558
Joined: 29 Nov 2008, 12:55am

Re: Max Sprocket Size for Campag 10 Speed

Postby CREPELLO » 20 Jun 2012, 9:09am

On my Cheviot with a 29mm long mech hanger I can get a Campag Comp long cage mech to work with a 11-32T shimano cassette. It would benefit from a longer hanger though.

It works. It's not perfect, although I have perfect gear changes now, I feel it runs just a little noiser on the largest three cogs, although I'm not sure why as the jockies clear the cogs.

It's easy to get the cage to clear the largest cog, but at the expense of crisp shifting on the smallest cogs, as the adjustment has taken the mech so far away from cogs.

I would be interested to know how the geometry of the mech differs to that of a Deore mech.

phil parker
Posts: 1019
Joined: 31 Dec 2009, 5:09pm
Location: Hants/Wilts

Re: Max Sprocket Size for Campag 10 Speed

Postby phil parker » 20 Jun 2012, 9:03pm

I've used a 30t Marchisio sprocket with a medium cage mech with no problems, although I wouldn't have stretched it to 31!

Valbrona
Posts: 2291
Joined: 7 Feb 2011, 4:49pm

Re: Max Sprocket Size for Campag 10 Speed

Postby Valbrona » 21 Jun 2012, 1:31am

phil parker wrote:I've used a 30t Marchisio sprocket with a medium cage mech with no problems, although I wouldn't have stretched it to 31!


So 31 and above would mean that the cage hits the sprocket(s)?
I should coco.

phil parker
Posts: 1019
Joined: 31 Dec 2009, 5:09pm
Location: Hants/Wilts

Re: Max Sprocket Size for Campag 10 Speed

Postby phil parker » 21 Jun 2012, 5:46am

Valbrona wrote:So 31 and above would mean that the cage hits the sprocket(s)?


Yes, it would with my set-up!

I can't speak for all combinations though.

Valbrona
Posts: 2291
Joined: 7 Feb 2011, 4:49pm

Re: Max Sprocket Size for Campag 10 Speed

Postby Valbrona » 21 Jun 2012, 2:17pm

Thanks for that. I kind of thought that 30 might be the max before the cage hits the sprockets, even though you can get after-market offerings of 32 and 34.

I also use a medium cage.
I should coco.

User avatar
NUKe
Posts: 3867
Joined: 23 Apr 2007, 11:07pm
Location: Suffolk

Re: Max Sprocket Size for Campag 10 Speed

Postby NUKe » 25 Jun 2012, 4:38pm

I am runnung a 13 28 tooth cassette with Campag Veloce 2010 Short cage mech and compact 34 50 front chainset, with no problems
The size of the cage does not determin the Max size of the rear sprocket. This is determined by the hanger, the pantogram and the b screw adjustment. The cage length determins the maximum total difference in teeth from the front and rear so for me that is 50-34 = 16 front and 28-13 = 15 reargiving a total of 29 teeth. I do still have some adjustment so could possibly get away with 13 29 I try not to use either of the extremes either 'small to small' or 'big to big' rings, but the cage is big enough to take the extremes so its safe. YOU would need a medium or long cage for a triple.
Last edited by NUKe on 26 Jun 2012, 11:01am, edited 2 times in total.
NUKe
_____________________________________

Valbrona
Posts: 2291
Joined: 7 Feb 2011, 4:49pm

Re: Max Sprocket Size for Campag 10 Speed

Postby Valbrona » 26 Jun 2012, 1:22am

NUKe wrote: The size of the cage does not determin the size of the rear sprocket.


Yes, we know. No-one has suggested otherwise.

For anyone interested in this thread it is my guess that 30 is about the limit for the old style Campag rear mechs with the B screw on the hanger. Fit a 32 or 34 and it might mean that you run out of B screw adjustment and the cage hits the sprockets, but I stand corrected.
I should coco.

User avatar
NUKe
Posts: 3867
Joined: 23 Apr 2007, 11:07pm
Location: Suffolk

Re: Max Sprocket Size for Campag 10 Speed

Postby NUKe » 26 Jun 2012, 9:54am

Valbrona wrote:
NUKe wrote: The size of the cage does not determin the size of the rear sprocket.


Yes, we know. No-one has suggested otherwise.

For anyone interested in this thread it is my guess that 30 is about the limit for the old style Campag rear mechs with the B screw on the hanger. Fit a 32 or 34 and it might mean that you run out of B screw adjustment and the cage hits the sprockets, but I stand corrected.

It might not have been ment but by talking about the fact you and Mick F and Phil T say you are using medium cages gives the impression that a medium cage is required. I was Just clarifying for anyone else that might want to pick up on the thread, and adding to the general knowledge.
NUKe

_____________________________________

User avatar
Mick F
Spambuster
Posts: 49155
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Max Sprocket Size for Campag 10 Speed

Postby Mick F » 26 Jun 2012, 10:04am

The cage size does indeed not have a bearing on the max sprocket size, but if it is 30t, what cassette and chain set would be normally used?

The cage size determines the max capacity of the drive train. If the 30t is with a 12-30 cassette and you have and a 36/52 double, you need a capacity of (30-12) + (52-36) = 34

No doubt many people know this already, but I thought I put the record straight. :wink:
Mick F. Cornwall

User avatar
CREPELLO
Posts: 5558
Joined: 29 Nov 2008, 12:55am

Re: Max Sprocket Size for Campag 10 Speed

Postby CREPELLO » 3 Oct 2012, 9:05pm

CREPELLO wrote:On my Cheviot with a 29mm long mech hanger I can get a Campag Comp long cage mech to work with a 11-32T shimano cassette. It would benefit from a longer hanger though.

It works. It's not perfect, although I have perfect gear changes now, I feel it runs just a little noiser on the largest three cogs, although I'm not sure why as the jockies clear the cogs.

It's easy to get the cage to clear the largest cog, but at the expense of crisp shifting on the smallest cogs, as the adjustment has taken the mech so far away from cogs.

I would be interested to know how the geometry of the mech differs to that of a Deore mech.
It's clear from looking behind the rear mech that the angle of the slant parralellogram is greater on a Deore type mech than a Campag rear mech (Triple Comp long cage mech). This means that the Deore follows the profile of wider range MTB cassettes more accurately than the Campag does (of course this makes sense in that Campag would have spec'd the parralellogram typically for close range road cassettes.

The B tension screw still performs the job on the Campag mech of pulling the jockey cage away from the largest sprocket, but at the expense of crisp shifting in the smallest sprockets. If the rear mech hanger was longer, this may possibly overcome this issue, but it seems that circa 30mm drop is the common standard (it is on all five bikes I've got, albit they're all touring type machines and a MTB).

I'm on the verge of swapping out the Triple Comp on my Cheviot for an XT rear mech because of this compromise (most changes in the small cogs are fine, but every so often it misses) and that the mech is definately noisier (despite the pulleys clearing the largest cogs) than an XT on my Dawes Audax . I wonder whether the smaller 10T jockey wheels on the Campag could be a cause of the increased noise??? XT is 11T.

Edit: just to add that the B tension screw on the XT/Deore is almost surplus to requirement on many cassettes - I actually took it out on my Dawes running an 11-30T cassette.

Brucey
Posts: 39316
Joined: 4 Jan 2012, 6:25pm

Re: Max Sprocket Size for Campag 10 Speed

Postby Brucey » 3 Oct 2012, 10:21pm

fundamentally there is another problem, which is with the double-spring arrangement (which Shimano dubbed 'servo pantograph' years ago, even though it wasn't really their idea.... :roll: ).

The double-spring arrangement has the distinct drawback that the springs cannot be a flat enough rate, stiff enough, and still small enough to fit into the space allowed. This means that the movement of the upper and lower pivots is accompanied by a change in the force at each pivot. This ultimately limits the ability of the mech to track the block; if the springs didn't vary in force as they do, the pulley to block distance could be almost constant, even without a slanted paralellogram.

BTW it is often worth trying different chains before ditching a transmission arrangement; they can vary very much in noise and shift quality.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
CREPELLO
Posts: 5558
Joined: 29 Nov 2008, 12:55am

Re: Max Sprocket Size for Campag 10 Speed

Postby CREPELLO » 4 Oct 2012, 9:35am

Good point that. It's not really a servo mechanism is it, at least not one that performs effectively the job required of it.

Shimano put their B tension screw adjustment on the top pivot, Campag put theirs on the lower pivot. I wonder whether one has any advantage over the other?

In relation to my particular issue (above), I wonder if I was to put a spacer between the blank 'B stop' of the Campag mech and the hanger it might change the behaviour of the double spring pivots in my favour?
This would seem to give me two B tension adjustments!