# Will Shimano 105 rear derailleur accept sram 12-32 cassette?



## Junior77

What do you think?


----------



## PlatyPius

No.

*Maybe* if it's a 105 triple rear derailleur, but just a qualified maybe.


----------



## onespeedbiker

Junior77 said:


> What do you think?


No, the max size cog for Shimano road derailleurs these days are 28T. There is no difference with the long cage version, they can simply take up more chain.


----------



## PlatyPius

onespeedbiker said:


> No, the max size cog for Shimano road derailleurs these days are 28T. There is no difference with the long cage version, they can simply take up more chain.


You'd be amazed at what you can make work if you try hard enough. Hence my "qualified maybe" statement.


----------



## Matador-IV

I use an 11-32 on my cross bike 105 short RD.


----------



## onespeedbiker

PlatyPius said:


> You'd be amazed at what you can make work if you try hard enough. Hence my "qualified maybe" statement.


Let me qualify that also by saying that Shimano rates their 105 derailleur at 28T; however there is this Sheldon Brown article on how to increase that Downgearing Your Bike.


----------



## LongIslandTom

I use an 11-32 on a Shimano 105 5700GS rear derailleur. No problems.

You CAN use a 11-32, as long as your derailleur hangar is long enough to allow your RD's pulley to clear the big 32T cog on the cassette.


----------



## Kontact

PlatyPius said:


> You'd be amazed at what you can make work if you try hard enough. Hence my "qualified maybe" statement.


Your qualification was for the long cage derailleur, which doesn't make any sense if they are both 28T max.



The capacity is based on the use of a short derailleur hanger. If the hanger is on the long side and chain length is just right you might get up to 32 with the B screw cranked down, but you won't know if it will work (or how well) until you try. You might end up with something that shifts, but hesitates and sounds bad.

The cage length affects wrap capacity only.


----------



## RussellS

My brother used a short cage Shimano 600 rear derailleur with a 11-32 cassette. On a Trek OCLV 5200 frame.


----------



## tednugent

I have heard from Shimano that the 2012 105's will be spec'd to 30T, which you can sneak in the extra 2 teeth.

I called Shimano a few weeks ago about the same question.


----------



## PlatyPius

Kontact said:


> Your qualification was for the long cage derailleur, which doesn't make any sense if they are both 28T max.
> 
> 
> 
> The capacity is based on the use of a short derailleur hanger. If the hanger is on the long side and chain length is just right you might get up to 32 with the B screw cranked down, but you won't know if it will work (or how well) until you try. You might end up with something that shifts, but hesitates and sounds bad.
> *
> The cage length affects wrap capacity only.*


Yes, and 11-32 is a pretty big range. I've had much better luck with long cage rear derailleurs as far as the chain not being too long in the small-small yet still long enough in the large-large combos. A short cage is going to limit that somewhat, if it works at all. Therefore, the odds are much greater that a long cage derailleur will work in this case.


----------



## LongIslandTom

For my setup, 50/34 front and 11/32 back, it requires a chain-wrap capacity of 16+21 = 37. The published chain-slack take-up capacity for the short-cage SS 105 derailleur is 33T, so I had to go with the GS medium-cage, which has a chain-slack takeup capacity of 39T.

You can probably get away with using an SS on an 11/32 casseette if you are running a double with a smaller difference between the chainrings, like a 50/38 or something.


----------



## Kontact

LongIslandTom said:


> For my setup, 50/34 front and 11/32 back, it requires a chain-wrap capacity of 16+21 = 37. The published chain-slack take-up capacity for the short-cage SS 105 derailleur is 33T, so I had to go with the GS medium-cage, which has a chain-slack takeup capacity of 39T.
> 
> You can probably get away with using an SS on an 11/32 casseette if you are running a double with a smaller difference between the chainrings, like a 50/38 or something.


That's wrap capacity - the amount of movement the lower pulley has. We're talking about maximum cog capacity - the ability of the upper pulley to clear the largest cassette cog and shift a chain onto it. Completely different problems.

There are several short cage mountain derailleurs that have smallish wrap capacity but can shift up on to 36T cogs, and there are long cage road derailleurs with huge wrap capacity but won't shift up onto anything larger than 28T.


----------



## LongIslandTom

Kontact said:


> That's wrap capacity - the amount of movement the lower pulley has. We're talking about maximum cog capacity - the ability of the upper pulley to clear the largest cassette cog and shift a chain onto it. Completely different problems.
> 
> There are several short cage mountain derailleurs that have smallish wrap capacity but can shift up on to 36T cogs, and there are long cage road derailleurs with huge wrap capacity but won't shift up onto anything larger than 28T.


I'm not talking about your problem. I was explaining why a GS was recommended when running a 32T cassette with a compact double setup (for the additional slack takeup). I've already covered the need for the upper pulley to clear the biggest cog in my first post way up there (longer derailleur hanger).


----------



## minutemaidman

I use a 50/34 compact crank and a SRAM 11-32 cassette with a 5700 med cage RD. It works great. It has been my experience that this will work fine on most frames.


----------



## Junior77

minutemaidman said:


> I use a 50/34 compact crank and a SRAM 11-32 cassette with a 5700 med cage RD. It works great. It has been my experience that this will work fine on most frames.


How do I know which RD I have. I am also running a 50/34 compact with 5700 RD. Per shimano's website there are only two derailleur choices. no idea which I have.


----------



## Kontact

LongIslandTom said:


> I'm not talking about your problem. I was explaining why a GS was recommended when running a 32T cassette with a compact double setup (for the additional slack takeup). I've already covered the need for the upper pulley to clear the biggest cog in my first post way up there (longer derailleur hanger).


Well then, to address your other post, you didn't "have to use a GS". You only need the derailleur capacity to match or exceed your system capacity if you plan on using both crossover gears. If you can avoid the temptation to ride around in the 11 or 12 x 34, you can get away with using a short cage derailleur and have enough capacity to shift into the 50x32. As I have for the last 15 years.


----------



## jeepseahawk

I just put a 11-30 on 105 rd ss with compact up front, it works with b screw all the way in. Less than 1 mm of clearance so I am taking off until I get a GS or mountain derailleur.


----------



## jeepseahawk

You have a SS (short) most likely with a compact, especially with a cassette 28 or lower. Triple up front usually have the GS (long).


----------



## Erik_A

The 2013 Sora RD may not be bling, but Shimano rates them at 32t out of the box.


----------



## cxwrench

Erik_A said:


> The 2013 Sora RD may not be bling, but Shimano rates them at 32t out of the box.


eh, it's only a year and a half, but here ya go...

View attachment 277404


----------



## Ranger1942

*105 with the 11-30*



jeepseahawk said:


> I just put a 11-30 on 105 rd ss with compact up front, it works with b screw all the way in. Less than 1 mm of clearance so I am taking off until I get a GS or mountain derailleur.


Requires a long B adjustment screw. I went with a drop out adjustment screw but found I had to design a piece to engage the dropout point on the bike because as you adjust in the angle of the screw pushes it off the adjustment boss.
Easy way I found to know if you've enough clearance is flipping the bike upside down and backpedaling the crank. If it rumbles the jockey wheel and cog are hitting.
The newer Tiagras (while heavy) handle the 30 t (and up to a 32 t).


----------



## AJ88V

cxwrench said:


> eh, it's only a year and a half, but here ya go...
> 
> View attachment 277404


Too funny!


----------



## jpegwun420

Matador-IV said:


> I use an 11-32 on my cross bike 105 short RD.


any tips for making that work?? I'm looking into the defy advanced 1 or 2 and i want a 32 cassette.
and maybe want to see if my anyroad comax can fit a 36 cassette


----------



## DaveT

A 34t or 36t cassette can't be used with a Shimano road rear derailleur. A 32t cassette may work if you're using a 5700, 6700 or 7900 rear derailleur, but you won't know until you try it out. There's no way to tell for sure except by someone's experience.

A Shimano 9-speed MTB rear derailleur is a great set up if you have to have a 32, 34 or 36 cassette, it works very well with Shimano road shifters.


----------



## junior1210

Or you could go get a MicroShift derailleur (RD-R51M for 10 speed or RD-R43M for 9 speed). Both are good up to 34T as per MS's site. I've used the RD-R51M for 32T cassettes with no hassle.


----------

