medium or short cage????????

goofyfoot

Folks advice please.Old git building up a frameset and will be using compact with 11-28 .Can I use a short cage rear mech or is a medium more suitable?Thanks

sylvanus

If its Campag then you'll need medium

tonye_n

And if Shimano......
The new short cage rear mechs (6700,5700, 4600) will take 11-28 no problem. Shimano specifies as such.
According to Shimano the older rear mechs (7800, 6600, 5600) will take a maximum 27t largest cog.

However my 08 Specialized Roubaix came stock with Ultegra 6600 short cage rear and 11-28 SRAM cassette (shimano did not do 11-28 at the time). This worked without any problems for 6 months until I switched to 12-27 which I prefer for the closer ratio.

dodgerdog

And SRAM. Limit on Rival short cage is 28T, anything larger needs the medium cage mech

dabber

sylvanus wrote:

If its Campag then you'll need medium

Dumb question... how do I know if my Campag is short or medium?

Mad Roadie

isn't there a trend in the pro-peloton towards long cages for less resistance in the chain?

sylvanus

how do I know if my Campag is short or medium?

Look here - 55m to 72.5mm between pulley axles (!)
http://www.campagnolo.com/repository/do ... 195_GB.pdf

And reading the article below which shows a Sheldon like level of knowledge, it appears the OP may be able to get away with short cage if needed:

http://branfordbike.com/articles/rear-d ... s-pg62.htm

dabber

Thanks sylvanus.... ruler at the ready.

rolf_f

I sometimes use Campag short cage with 13-29. It looks like there might be space to handle another tooth so possibly 11-28 would work.

dabber

sylvanus wrote:

And reading the article below which shows a Sheldon like level of knowledge, it appears the OP may be able to get away with short cage if needed:

http://branfordbike.com/articles/rear-d ... s-pg62.htm

I've just been looking at this link and I'm finding it a bit confusing in the area of chain wrap.

My bike has (I now find a short campag cage). It came with 50/34 compact and 12/25 on the rear. Fairly standard setup.
According to this article that gives a calculation of 16 + 13 = 29

According to the article a short cage only supports upto a factor of 27.

In fact I now have a 12/27 which gives a revised calculation of 31.
Both the original setup and the revised one run perfectly. I'm just a little suprised that the standard (off the shelf) setup was outside the parameters of the recommendation?? Am I missing something?

sylvanus

I'll have to read it in full but think you're right - modern short cages will now manage almost any combination. Now beginning to wonder what I'm running on different bikes but away from home today so will dust off my ruler and calculator tomorrow.

goofyfoot

thanks all for replies..... shimano short cage it is then.

g00se

Dabber wrote:

My bike has (I now find a short campag cage). It came with 50/34 compact and 12/25 on the rear. Fairly standard setup.
According to this article that gives a calculation of 16 + 13 = 29

According to the article a short cage only supports upto a factor of 27.

In fact I now have a 12/27 which gives a revised calculation of 31.
Both the original setup and the revised one run perfectly. I'm just a little suprised that the standard (off the shelf) setup was outside the parameters of the recommendation?? Am I missing something?

What year is the kit? The more recent Campag mechs can handle 29 teeth on the biggest sproket - so I suppose chain capacity may have changed?

Also, I know that 27 was the 'official' max chain capacity for Campag mechs in the last decade, but they would all stretch to 28 or 29*. Further, depending on the length of the chain stay, you could possibly get away with a couple more. This was dependent on whether the pulley cage accommodated just the right amount of slack chain ( as one link = half an inch of chain) or if it also had to take up some extra slack as the optimum run around the chain line didn't fall on a half-inch.

If you google 'park tools', 'chain length' and 'rigorous formula' - there is a calculation using your chain stay length, and chainset/cassette teeth counts to work out your ideal chain length. If this falls very near a full inch, then you can get away with more capacity.


* The fact that the chain capacity and also the teeth on the biggest cog are similar is just plain confusing sometimes....

rothers_bikeo

goofyfoot wrote:

Folks advice please.Old git building up a frameset and will be using compact with 11-28 .Can I use a short cage rear mech or is a medium more suitable?Thanks

Double on front short cage will do, triple you'll need a medium cage.