totalnewbie

I am thinking of ordering a Canyon bike with ultegra di2. However, the Canyon rep told me that they only offer up to 11-28 cassette. My weak legs tell me I need more, eyeing on the 11-32, which is not what canyon can offer at this point.

OK, I can buy the 11-32 cassette myself since it is not that expensive, however, I read that there are two rear derailleur options for new ultegra di2 6870: SS for up to 28 teeth and GS for up to 32 teeth. If Canyon can only supplies the SS version (my assumption) then what are my options in order to use 11-32?

Do I have to buy a whole different derailleur (GS) and sell the SS one? Or are there replaceable parts on the SS that I can change inexpensively?

robbyville

According to Leonard Zinn, they have had great success taking the long cage version of the 6800 (mechanical) derailleur and putting it on the Dura Ace 9070 so presumably it would work with the 6870 derailleur as well, might be the cheaper opportunity since you could buy the med cage 6800 derailleur for perhaps $120 (fraction of the DI2), swap the cage to your 6870 and then resell the derailleur as a short cage. If you're going through an LBS, most will be happy to do a credit and swap of some sort once the longer cage DI2 derailleur is available (I have heard in Jan-Mar). You will probably also need to add a couple of links to your chain.

FWIW since I was thinking of doing something similar with my DA... I have a compact crank and 11-28, 44 years old active but not super strong and while there have been a few times with really hard climbs that I've thought I needed the 32t the combo of 34x28 has really been fine.

good luck!

Roadrash3

I wish i understood all the bike components more. I had my local bike shop here do it and it is possible. I wanted a lower climbing great, they changed the rear cage, and i put on a 11-32 cassette. When i first did it, i only had ultegra not Di2, last month i had them change everything to di2 and we did not change the set up on the bike at all and with ultegra it works great. I say go for it, i love that set up

totalnewbie

based on what you said, i did a little google search and find the following official shimano PDF listing the parts of 6870 SS vs GS and whether they are interchangeable with 6800.

si.shimano.com/php/download.php?file=pdf/ev/EV-RD-6870-3641.pdf

inner plate... fine
outer plate.... fine
BUT the plate axle assembly is not interchangeable.

If I understand this correctly (and I know nothing about parts) even if I buy a 6800 GS, I can fit the inner plate and outer plate on the 6870 SS but I am still stuck with the plate axle assembly. What exactly is the plate axle assembly I have no idea, but will it be a deal breaker?

robbyville

Great job on the research!

You should be able to use the axle from the original 6870. That being said, remember I have not personally done this but Leonard Zinn from Velo News has many times with the Dura Ace 9070 rear derailleur and has become a regular fix at his shop. You may want to take a look at that site.

donrhummy

You could also stick with the 11-28 and choose one of the other crankset options. There's a 53-39, 50-34, 52-36, 46-35. The 50-34 might give you the same benefit.

totalnewbie

further research indicates that for this "axle plate assembly", there are four different part numbers for 6800ss, 6800gs, 6870ss and 6870gs.

yet for 6700 there is only one single part number for both ss and gs. 6770 has a different number from 6700 too (ss only)

si.shimano.com/php/download.php?file=pdf/ev/EV-RD-6870-3641.pdf
si.shimano.com/php/download.php?file=pdf/ev/EV-RD-6800-3608.pdf

does anyone know if this axle plate assembly is indeed not interchangeable?

robbyville

Ditch the 6700 stuff from your mind, totally different. As mentioned you may want to email through Velo News Leonard Zinn, he does it often with the Ultegra mechanical to Dura Ace electronic often, however I don't think you'll find anyone yet who has done Ultegra to Ultegra since the 6870 stuff is only now starting to hit the market and even then pretty much all from the UK, I'm making an assumption but I don't think you'll find anyone with real world experience here for the next month or two. But again, the DA stuff is off the same basic construction and if people are doing it Ultegra to DA, then I'm sure they cold also do Ultegra to Ultegra.

hamster

There is a good chance that 11-32 will work out of the box, just with the B-screw screwed in backwards. I have it set up like that and there's some light noise that I only hear in 32T, but pulleys technically clear the cassette so it's not an issue. (A bigger issue is having to be very precise with the chain length whenever you change chains: 11-32 + 50-34 utilizes almost the entire range of the SS derailleur, and, if the chain length is off by even a couple of links in the wrong direction, either you have the RD going slack in 34/11, or you can't shift into 50/32. Both situations are unpleasant and potentially dangerous.)

You have to think about the prices. If you're comfortable with the idea of buying a 6800 RD, swapping cages and then reselling it as short-cage (particularly with the last part), that's probably cheapest. 6800/6870 market is pretty thin at the moment, but I don't think it's going to set you back much if you simply take off your 6870 SS as soon as you get the bike, sell it as new/take-off and buy a 6870 GS.

GaryPitts

I've been running a 12/32 cassette on my Di2 Domane since mid-summer. No problems and no changes except for reversing the B screw on the derailleur. If I go big-big on the gears, the chain is pretty tight. It could use another link or two. But even at that, I've had no trouble at all.

Ultegra comes in a 12/30 cassette if you think two additional teeth would suffice.

robbyville

Gary, are you running the 9070 derailleur with your 11-32?

GaryPitts

Heck, I don't know It's whatever came standard with the 6770 derailleur https://bike.shimano.com/publish/cont...ra_brings.html