Ultegra Di2 Compact 50/34 with 11-32 cassette?

[altecsole]

When I bought my Focus Cayo Di2 it came with a 52/36 chainset and a 11/28 cassette.
I changed the cassette to a 11/32. I later changed the chainset to a 50/34.
Both items went straight on with no further modifications.

Many thanks. Most bikes I've looked at only seem to offer 50/34 and 11/32 on endurance bikes and quite often they come with disc brakes, whereas I'd rather have rim brakes. Obviously swapping cassette and chainset is an option and it's good to know that is a possibility as long as I get the longer rear mech. Cheers.

 

[Dirk]

How tall are you? If you change the crank length, you'll need to change the saddle position/bike set up to compensate. Personally, if just changing components I wouldn't mess around with sizing if you're happy with the fit and set up. That way madness may lie (not to mention aches and pains)

When I changed my chainset, the only one I could get at the sale price was with 170 mm cranks, as opposed to the 172.5 mm ones I have been using.
I haven't altered anything else on the bike and have not noticed any difference with the shorter cranks.
2.5 mm is negligible. I reckon you'd have to be a 'princess and the pea' type for it to matter.

 

[CerveloMad]

Sorry, my apologies - mech cage. The mech body is identical regardless.

I appreciate this is an old post and unsure which model Di2 is being referred to here, but for the record, the 6870 series Short cage(SS) and Long/Med cage(GS) rear derailleurs are not identical. The difference, besides the longer cage plates, is that the knuckle of the GS is marginally lower than that of the SS, so that there is a bigger gap between the top pulley of the derailleur and the largest cog. You can sometimes just about get away with using the SS with a larger cog, dependent on the mech hanger design, but for anyone reading this, beware, it's not always possible with the majority of set ups.

 

[CerveloMad]

One more for the record and against Shimano's rule book, I have today just fitted to an 11-34 cassette to a 6870 Di2 long cage rear mech without any problems. This was on a Trek Madone with a 50/34 compact up front. I needed to screw the B stop in all the way but plenty of clearance with the top pulley and 34 cog plus no chain sag with the 11T cassette cog/front 34T chainring combo. As I mentioned in my last post, going up to a larger rear cog without it hitting the RD top pulley may not be possible on all bikes so again, bear this in mind.