alloy Chorus 10s RD question

[bumknees]

I have an alloy Chorus 10s rear derailleur. On the box, it's labeled "type L" (presumably for Long Cage), but the cage length appears to be identical to my carbon Chorus 10s medium cage RD.

I know that the newer 10s medium cage RDs can be used with triples, but can this alloy RD also be used with a triple (53/42/30) and a 12-25t cassette? The instructions included says that this RD only has a capacity of 30.

I've attached some pics for reference.

Thanks!

[AngryScientist]

retracted for better advice below...

[oliver1850]

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[bumknees]

I'm pretty sure it's a 1999 (at least that's the date on the instructions). The derailleur says 10 speed, and the box was labelled "type L."

[Ralph]

In those days, what they called long cage is now a medium cage. Most of those old derailleurs were "rated" to only clear a 26 tooth cog when used on a triple, but will handle the difference of a 30-42-52 and 12-25 (35 teeth). I don't know which year you have though. Newer ones would clear a 29 tooth in rear.

We know (from experience) that when using with a double, they will clear a 30 tooth or slightly larger rear cog, depending on hanger length. If you are decent at making stuff work, you can use this just fine.

[thwart]

I think the 30 is the chain wrap number.

From the interweb:
Chain Wrap or CW is a simple calculation that will help you determine whether the rear derailleur you choose has a long enough cage to take up the chain slack in your drivetrain. The shorter the cage, the lighter and stiffer the derailleur and the quicker it will shift. Calculate Chain Wrap to get the greatest shifting performance.
To calculate Chain Wrap Capacity [CW] determine the difference between your largest and smallest chainring. Then determine the difference between your largest and smallest cog. Add the differences and you have Chain Wrap Capacity.
Example: 42/52 chainrings and a 12/21 cassette yields a CW of 19. 52 - 42 = 10. 21 - 12 = 9. 10 + 9 = 19. So, with a 42/52 chainring and a 12-21 cassette you would need a rear derailleur that has a Chain Wrap Capacity of at least 19."

Let's say you have a 53-39=14 crankset and 29-11=18 cassette: 14+18=32 so your CW is 32; As an example, the CW for a 2004+ chorus rear short derailleur is 27. Chorus medium's CW is 36.

As has been mentioned here in the past, Campy has conservative chain wrap numbers... meaning you can go above this somewhat without problem.

[AngryScientist]

I think the 30 is the chain wrap number.

From the interweb:
Chain Wrap or CW is a simple calculation that will help you determine whether the rear derailleur you choose has a long enough cage to take up the chain slack in your drivetrain. The shorter the cage, the lighter and stiffer the derailleur and the quicker it will shift. Calculate Chain Wrap to get the greatest shifting performance.
To calculate Chain Wrap Capacity [CW] determine the difference between your largest and smallest chainring. Then determine the difference between your largest and smallest cog. Add the differences and you have Chain Wrap Capacity.
Example: 42/52 chainrings and a 12/21 cassette yields a CW of 19. 52 - 42 = 10. 21 - 12 = 9. 10 + 9 = 19. So, with a 42/52 chainring and a 12-21 cassette you would need a rear derailleur that has a Chain Wrap Capacity of at least 19."

Let's say you have a 53-39=14 crankset and 29-11=18 cassette: 14+18=32 so your CW is 32; As an example, the CW for a 2004+ chorus rear short derailleur is 27. Chorus medium's CW is 36.

As has been mentioned here in the past, Campy has conservative chain wrap numbers... meaning you can go above this somewhat without problem.

ahh, that does ring a bell, good call.

[oliver1850]

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[LesMiner]

10 speed was introduced in 2001,

I think Campy introduced 10 speed few years before 2001. I have 1998 Raleigh Professional that came stock with Campy Chorus 10 speed.

[bumknees]

pics added for reference

[Germany_chris]

Wiki says 2000 also

[oldpotatoe]

In those days, what they called long cage is now a medium cage. Most of those old derailleurs were "rated" to only clear a 26 tooth cog when used on a triple, but will handle the difference of a 30-42-52 and 12-25 (35 teeth). I don't know which year you have though. Newer ones would clear a 29 tooth in rear.

We know (from experience) that when using with a double, they will clear a 30 tooth or slightly larger rear cog, depending on hanger length. If you are decent at making stuff work, you can use this just fine.

Yep, remember that Racing 'T' had the same cage length and was designed for use on triples and max 13-26(not 13-28/9 of the time).
That one will work fine with a triple and 12-25 or 13-26.

[oldpotatoe]

I think Campy introduced 10 speed few years before 2001. I have 1998 Raleigh Professional that came stock with Campy Chorus 10 speed.

10s was introduced by Campagnolo in 2000. 9s in 1997.

[bumknees]

Thanks everyone for the information! This will complete my all alloy 10s Campy build (1999 Athena shifters, Record triple crankset and FD, Chorus RD, Record threadless headset, Record hubs). I just wish my hubs were silver instead of black...