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Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sat Jul 13, 2019 9:38 am
by Catagory6
If so are there instructions, and where might I source a medium cage?

Or is it possible to use a 10-speed RD and change the anchor point of the cable?

Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sat Jul 13, 2019 9:38 am
by Weenie

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sat Jul 13, 2019 12:15 pm
by alcatraz
It won't support larger cassettes.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sat Jul 13, 2019 3:39 pm
by Catagory6
alcatraz wrote:
Sat Jul 13, 2019 12:15 pm
It won't support larger cassettes.
what wont? if i switch out the cage?
is the parallelogram different dimensions?
i use a wolf tooth road link

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sat Jul 13, 2019 11:30 pm
by alcatraz
The parallelogram is the problem. Not the cage. Manufacturers use cage size to classify but thats only half of the design change to support different cassettes.

Sure you can use a road link but it will never work as well as a normal within spec setup.

Everyone has a different opinion about what good shifting is. In the long run riders usually tens to gravitate towards working solutions and in our group we max out the derailleur without road links. The cost in performance is too high when going road link.

For medium cage (non campy) we max at 36-38t cassettes. For short cage we max around 30-32t. If someone wants bigger they need to swap the derailleur.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 12:38 am
by Calnago
Short cage, pre 2015, practical use depends partly on how big a cassette you want to run. It’s capacity is 29tooth, but capacity beyond that will depend on your frame and hanger geometry with the usual “use at your own risk” kind of caveats. The actual process of physically swapping cages is not that difficult. Just how big a cassette do you want to run? If your roadlink lowers the pivot point enough then the parallelogram track shouldn’t be the issue as much as compromised (not as crisp) shifting in the mid to smaller cogs.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 1:02 am
by alcatraz
I've noticed poor shifting on original setups especially between the 11th to 10th cog.

A road link just makes that existing issue even more severe. If you're lucky to have perfect shifting without a road link then you might get away with using one. If you have any issues at all stay away.

Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 1:07 am
by Calnago
Campy doesn’t even make a cassette with a 10tooth cog, thank goodness. Of course the further away the upper pulley is from the cogs, the less crisp the shifting will be, but doesn’t mean it can’t be done if you’re willing to compromise a bit so long as there’s no danger of exploding the drive train. Hence my question about just how big a cassette the OP wants to use.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 2:14 am
by alcatraz
11th and 10th cog being the last two cogs regardless of their size.

Some derailleurs are better like the latest generation shimano. 7000/8000/9100.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 11:30 am
by bm0p700f
The max tooth count for a chorus rd is 29t its capacity is larger or I would not be able to run a 12-29t with z double chainset. I think the capacity is something like 32t. I cant find the relevant documents to confirm.

There are no medium cage available any way. You could use an athena medium cage rd but has another complication due to the difference in spring tension between athena and chorus in the rd.

The current short cage rds can be turned into a medium cage with the proenza cage.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 12:45 pm
by raisinberry777
bm0p700f wrote:
Sun Jul 14, 2019 11:30 am
There are no medium cage available any way. You could use an athena medium cage rd but has another complication due to the difference in spring tension between athena and chorus in the rd.
Could you use a 10 speed medium cage derailleur? I guess the issue there is the geometry - not really made for a cassette as wide as 11-32.

Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 2:34 pm
by Calnago
Back around 2000, Campy made a Record level triple 10sp crank. Up until that time they had Athena and “Racing T”. I have all those cranks still sitting in my garage. The Record Triple was a beautiful crank, with 30/39/53 rings. So you had the beloved standard combo but with a really great “climbing” ring when you needed it. That groupset also had available a 13/29 cassette, dinnerplate size back then, and was quite an embarrassment on a proper road bike to be honest. You would use the long cage with that setup, and the long cage also added to the embarrassment. I used to do a lot of overseas trips back then and since climbing was never my forte, I combined the triple with the medium cage and a 12/25 cassette. This gave me the range afforded by the triple crank but the closer ratios of the tighter cassette. It was perfect although when on the small 30 tooth ring, the mid cage didn’t have quite the capacity to wrap enough chain to make the smallest 4 cogs useable; for full use of all combos you would need the long cage, but ugh, it hurt my eyes to look at it. At least the smallest granny ring up front was hidden behind the beautiful 39/53 Record rings, so I could live with that. And that combo served me well in the French Alps and beyond.
So, you could use the short cage for smallish cassettes and a double standard crank up front, the medium cage for the “monster” 13/29 cassette at the back and double crank up front, and the long cage for the full Monty triple Record crank plus the dinner plate (13/29) at the back. Eventually, the manufacturers started the “compact” double so that it wasn’t such and embarrasment to go with less than manly gearing (triple). But that triple still provided the best of all worlds, retaining a huge range but also close ratios. It’s kinda funny how things have evolved to it seemingly being “ok” (by some standards) to have a single ring up front with a cassette the size of a hoolahoop at that back. It’s just an awful setup for the road. And makes that triple I had back in 2000 look like a “he man” setup in comparison.

But to answer your question, I’m not sure if you could just swap in a 10sp mud cage derailleur on the pre-2015 11sp rear derailleurs. I’ve never tried it. The geometry and effective cable pull would likely be different enough to not work well with cassettes with cogs larger than 29 teeth. But I don’t know that you couldn’t just throw on a potenza cage either. I know there was some talk of different spring tensions etc, but in most of my Super Record derailleurs I’ve changed the placement of the cage spring to the highest tension slot from the default middle slot with no ill effects while giving it better ability to adjust closer to the cogs. Campy made a running change in the ratchet wheel that the H-screw mates with to basically accomplish the same thing I was doing by moving the spring to the higher tension hole before that change was made.
I know I gave a little more “history” here than may have been warranted but I often find it fascinating how things change, yet remain the same as far as wants and needs go. I truly think that a nice triple with a close ratio cassette on a road bike is far more functional and certainly more aesthetically pleasing on a road bike than a single “mid size” ring up front coupled with a wide range wide ratio cassette at the back with a cog up to a godforsaken 40-50 teeth with a massively long cage. Looks so wrong on a road bike. Please, bring sexy back, cuz a 40-50tooth cassette at the back just ain’t it on a road bike.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Sun Jul 14, 2019 6:52 pm
by bm0p700f
The athena triple rear derailleur would have enough capacity and the correct geometry but the spring tension in a power shift rd is lower than ultra shift rds so while it will shift you may fo d the shifting deotoriates more quickly. This will be more of a problem on bikes which have excess cable friction. Record linkage rear derailleur is can cope with big cassettes but are unavailable. The medium cage can deal with a 12-32t but I used that worh a double with 10 speed.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Fri Jul 19, 2019 2:33 pm
by c50jim
To get back to the original question, I had the same question when I decided to put an 11-32 on my travel bike a few years ago. I bought an Athena mid cage thinking (hoping?) thaat my mechanic could just swap the cage as he'd done with various 10 speed Campy derailleurs. Unfortunately, the cages couldn't be swapped. So I ended up with a Chorus group with an Athena mid cage derailleur. Worked fine and is now on a Campy gravel bike working fine again with an 11-32 Shimano cassette and Chorus 50-34 compact crank.

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Wed Jul 24, 2019 2:12 pm
by Catagory6
i did not know that parallelogram geometry changed depending on the length of the cage.
i thought that would remain a constant
but now thinking about it, the hyponetuse would be longer for an 11-34/36, than for an 11-28.
and the angle of travel is steeper too
so is that why the p-gram geometry needs to be different?

i would like to run an 11-34, or even an 11-36, with a 34-50

maybe the less complicated approach would be to just lose weight and get stronger?
cheaper too, huh?

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Wed Jul 24, 2019 2:53 pm
by alcatraz
11-36 on 50-34 is a nice allround combo.

But better do it with shimano/sram. Campy has always had a bit less range than the competition (triple cranks excluded).

If you don't have a shortage of time or money you could run one of those 9-32t cassettes with xd freehub on the current derailleur and try swapping the crank for a 46/30t or a 44/28 (e.g. white industries).

Re: Possible to convert a pre-15 chorus small cage RD to medium cage?

Posted: Wed Jul 24, 2019 2:53 pm
by Weenie