ahultin

Interesting note, there is a new Ultegra derailleur showing with compatibility for this cassette, the rd-6700A

goldfinch

I have a 2011 Madone with the 5700 group:

SHIFTERS / Shimano 105 STI, 10 speed
FRONT DERAILLEUR / Shimano 105
REAR DERAILLEUR / Shimano 105
CASSETTE / Shimano 105 11-28, 10 speed
CRANK / Shimano 105, 50/34

What would I need to change to get lower gearing?

10 Wheels

I have the 12-30.

Works Great with no other changes needed.
You won't miss the 11 cog.

https://www.ribblecycles.co.uk/sp/roa...te/shimcass926

vesteroid

There is an existing mid cage and short cage rd on 2012 bikes or before in ultegra (perhaps 105 as well)

my understanding is the short cage won't handle the 12-30

i was fortunate to have the medium cage but even so my chain was extremely tight when I installed the 12-30. I really should have had an extra link.

honestly I switched back to a 11-28. So...ymmv

the difference is not as profound as you may expect.

10 Wheels

Mine has the 105 short dérailleur. It works fine.....

goldfinch

Did you have to change the chain out?

10 Wheels

No other changes needed.

Just swap the cassettes.

Dunbar

The general consensus is that you can go 1-2 teeth larger than the rated capacity of a Shimano rear derailleur. The 2012 Shimano 105 rear derailleur is officially rated for a 30T low gear so you could probably run a 12-32 cassette no problem on the newest 105 stuff.

antimonysarah

Bumping an old-ish thread, but how do I tell if I've got a 2011 or 2012 105 derailleur? Where do I look on it? (I'm sure it's a short-cage.) Sounds like I probably could coax it to take 12-30 whichever I have, but I'm curious if I could get a 12-32 on it at all. I'm not sure if I want to switch up my gearing; I'm still getting back in shape, and I might be OK with my 50/34 x 11-28 eventually, and I do use the 11t. But it's also not that hard to change cassettes, so if it'd take them both, I could swap depending on what I'm riding.

magohn

I went through a similar deal last year. I live in a pretty hilly area and got tired of struggling on hills using my Roubaix 27T. I 'upgraded' the derailleur, chain and cassette to take a 36T. I have to say it was a little more involved than I expected BUT it is a huge difference for climbing. I did have a couple of chain drops in the miles since the thread but I don't think Id go back to 27T.

https://www.bikeforums.net/showthread...ht=magohn+sram

Just adding my 2c as a positive vote for making hills 'easier' by switching out your cassette. However, I like to tinker so unless you DIY, it could get pricey.

Dunbar

It's almost certainly the same year of your bike unless you bought it separately.

vesteroid

I have both the 28 and 30 cassettes on my wheels, so I now have almost an entire summer of riding on them. I just dont see all that much difference in them when riding. yes it is some, but honestly I dont seem to miss it all that much when i am on the 28. All I mean is if you are looking for night and day dont waste your money, if you need "just a little bit more" to get by the 12-30 may be enough.

mtalinm

I suppose this is the correct thread to gush about my hill-climbing setup:

24t small chainring on a triple crank
11-36 cassette with a long-cage derailleur and the b-screw flipped

i can barely maintain 3.5 mph on flat ground. and that's about how fast I went up Mt. Washington. but I made it at #270

antimonysarah

It's a custom, built this past (2012) August. The shop that built it would know, but I wanted to figure out how much I might be getting myself into changing before I took it in. They were right that the compact and 11-28 gave me as much as my old bike's triple, but I'm so much happier on it that I'm looking at more ambitious rides.

I just need a little more for what I want to do right now, but then I look at descriptions like mtalinm's and want something like that to try to bike the Kanc. Even though I hate hills.

Which means I think I should leave it as-is for now and train, and see how much more I want after the summer.

gsa103

I realize this is bumping an old thread.

How do you tell the difference between the RD-6700 vs RD-6700A? Is there a part number stamped somewhere?

I'm not a cylde, but I do routinely climb 8+% grades and need a new cassette so I'm considering swapping the 11-28 for a 12-30. I'm sure I have the GS cage.

Dunbar

Yes, it should be stamped on the RD.