Di2/Ui2 Compatibility to 6600 crankset?

FWIW.  I think this is stating the obvious, but since you are already committed to getting the Ultegra Di2 shifters & derailleurs, you may as well wait to see how well your 6600 crankset works, or not, before you pony up for a new crankset.

 

 

 

FWIW.  Okay, to preclude the long throw to shift to the outer chainring, choose the final gearing you want to use AND adjust the inner chainring SIZE when paired with an 11t, accordingly, so that you can start the sprint on the inner chainring and take advantage of the shorter throw of the inner paddle ....

 

So, presuming your final gearing for the sprint is a 53/12 (!?!), then calculate what size chainring you would use with an 11t -- i.e., I reckon tha you would the want a 48t-or-49t chainring inner chainring ...

 

• if you are ending up with a 53/11, then you probably deserve a sponsor

 

If your current largest cog is a 23t, then the consider a 27t as the largest cog ... 

 

THAT may not be an ideal stack for competitive racing, BUT you can simply stack a 27t MICHE cog on the end of your cassette current cassette (I'm presuming an 11-23) after you figure out which intermediate cog you are willing to sacrifice (i.e., 15t, or 16t, according to your preference or the particular race) ...

 

• the jump from the 21t  to a 27t should be little different from a shift from the 21t to a 25t ... maybe not

 

• if your current largest cog is a 21t, then you could choose a 25t-or-26t for the cog you restack onto your cassette OR simply use an 11-25 cassette.

 

In other words ...

 

ADJUST THE SIZE OF THE INNER CHAINRING ACCORDING TO THE SMALLEST COG YOU ARE ENDING UP ON IN THE SPRINTS .... you may decide on a smaller-than-48t chainring, of course.

 

So, for the sprint, you would simply have the chain on the inner chainring & take advantage of the shorter throw of the inner paddle to shift the chain to successively smaller cogs ...

 

• of course, you won't have to worry about the possibility of a thrown chain during the sprint, no matter how remote the likelihood

 

This will cost you a $10-or-so for the cog + the cost of the inner chainring (it does NOT need to be ramped, so any 48t-or-other-size 130BCD 3/32" chainring will work (of course, 1/8" Track chainrings are readily available in all sizes and cannot be used), so less than $30 on eBay) + time restacking the cassette & swapping chainings + testing with the bike in the stand + road testing to see if a larger inner chainring + restacked cassette will work for you ...

 

In my World, a cost of less-than-$50 is less expensive than the cost of Di2 shifters-and-derailleurs ... so, it seems like a worthwhile option to 'me' for you to consider.

 

 

I think the throw on the Campagnolo EPS levers & paddles is shorter than the throw on their mechanical shifters.

 

 

 

Because some people like the mechanical feedback, like a lot of Campy users. Also because one complaint about Di2 has been the lack of mechanical feedback. The mechanical feel of Campy's EPS is the result of the type of electronic switch chosen not a bunch of lever throw. It changes not one bit of the electronic function.

The thumb shifter is equally comfortable to access from the drops and the hoods. Some people with small hands or with limited range of movement in hands have complained about reaching the thumb shifter from the drops, but they are the minority. To address that complaint in EPS, Campy reconfigured the shape/location of the thumb shifter so that it is easier to reach for people with smaller hands.

You'll have to ask Alfeng about how Campy shifters work with Shimano drivetrains. The vast majority of people use Shimano shifters with Shimano drivetrains and Campy shifters with Campy drivetrains with absolutely no issues. I would venture to guess that people who use Campy shifters with Shimano drivetrains make up much less than 1% of Shimano users. Shimano has optimized their drivetrain and shifters to work best with each other as have Campy, but there will always be tinkerers. I do use a Shimano 11-28 cassette re-spaced by Wheels Manufacturing to Campy 10spd spacing because Campy doesn't have a 10spd 12-28/29 or 11-28/29. Campy does have a 13-29 cassette, but that spins out a bit early for my tastes on some of the descents around here. I like fast descents, so coasting more isn't as much fun. I figured that the Wheels Mfg cassette would shift better than any of the other aftermarket cassettes.

Re: using Di2/Ui2 w/ your 6600 crankset it's likely ok. On Weight Weenies forum and on the Fair Wheel Bikes forum, there are a bunch of people using 7800 cranks, THM Claviculas w/ Stronglight chainrings, FSA cranks, and etc. The spacing hasn't changed by Shimano claims that to use Xi2, chainrings need to be stiffer. If you suffer shifting issues w/ the 6600 crankset, you could always mount other chain rings, like those from Praxis. Praxis chain rings are supposed to be some of the stiffest chainrings out there and have been getting a pretty good rep at Weight Weenies, Fair Wheel Bikes, and at the magazines: http://praxiscycles.com/pages/standard-road-rings .

On double cranks, chainring spacing doesn't seem to be a big hurdle. When Campy moved to 11 speeds, the revised the spacing on the chainrings and the chain. Many folks are still using 10spd cranks and chainrings w/ Campy 11spd with zero issues.

Alienator,

The FSA DA79 is a very stiff be relitavely inexpensive chainring. Probably not quite as stiff as the Dura Ace 7900 ring but it's beefy, well ramped and it's what Cannondale are fitting to their uber sexy Si SL Hollowgram cranks. I think there's no coincidence that FSA called their new rings DA 79...

Danfoz,

If reaching the shifters from the drops is a concern and you're interested in Di2, there's always the additional sprint toggle switches that the likes of Cavendish have been using. You can put them whereever you like and just trim a little hole in the bar tape. I'm not sure if they're available for the 2 wire Ultegra Di2.

I think only Alf would suggest shifting chainrings mid sprint to just achieve a shorter throw. Whilst front shifting has improved greatly over the years I'd still rather deal with extracting my teeth with rusty pliers before risking my behind (and the collective asses of those around me) shifting chainrings during, or just before, a bunch gallop, even if there only a couple of other folk with me. It's been a longtime since I fluffed a front shift but then I never seem to change from the small to the big ring during a 800+ watt effort.

I don't doubt that FSA's chainrings are stiff. The scuttlebutt on the Praxis rings, though, is that they may even shift up at least as well as Shimano's. I have to admit I've a bias against FSA cranks. They have a well earned history of things coming loose in the BB/Crank system. I figure they've improved, but I've no urge to try them.

FSA, Praxis, and some others have copied the Shimano scalloped big chainring look unabashedly. I never particularly cared for the look. I thought older style Dura Ace cranks looked so much nicer.

 

 

FWIW.  You may-be-or-are right with regard to the EPS thumb lever location, but being of a certain age, it never occurred to me that the thumb shifters on Campagnolo's mechanical shifters OR the paddes weren't initially designed to be used from the Drops (ditto for Shimano's shifters) AND so I have always been stupified as to why people would set up the location of their shifters without THAT access in mind, first ...

 

And so, when the initial reviewers suggested that Campagnolo, Shimano, or SRAM have done this-or-that to accomodate smaller hands, I just have to wonder why people are positioning their shifters in a position which doesn't work well for them in both positions ...

 

Of course, the design engineers have made concessions to those who prefer a poor shifter location on this-or-that handlebar, but (IMO) it is must be easier for a person with small hands to set up their shifters in the right place (theoretically, this is what the LBS is supposed to be doing which they apparently aren't when they are providing a "professional" fitting) than for a person with larger-than-the-norm hands (i.e., where I will suggest that the "norm" includes those of  us who are under 6'0") ... with the really small (under 5'0") riders having the option of using a set of TERRY handlebars.

 

The number of people using a mixed drivetrain is probably LESS than 0.01% ... maybe, not even 0.001%.   

 

After about a dozen years ('I' was not the first, but my initial 'test' & utilization was done without knowlege that others had pioneered the mix-and-match by way of the hubbub.com cable connection and/or JTEK Shiftmate dongle), or more, one would not think that Campagnolo shifters as a substitute would not be considered to be the underground alternative that many still treat it as being ... 

 

IMO, while post-9-speed Shimano works better with other 10-speed Shimano components than with older Shimano components, based on the reviewers constantly saying that each successive generation of Shimano's components is better than the last suggest that there is still room for improvement, IMO.

 

While Campagnolo claims that their 11-speed cog spacing has improved the shifting (and, the incrementally closer cogs should certainly do that), I suspect that a greater benefit in Campagnolo's shifting has resulted from more closely mimicking the tooth profile of Shimano's cogs ... a benefit which I (and, the other 0.001%) have taken advantage of for years.

 

 

BTW.  This is a 10-speed Campagnolo cassette which I restacked with a 29t MICHE cog to create an 11-29 "Campagnolo" cassette:

 

 

Miche also has a 27t cog.  I can't recall if the pictured cog was originally intended for a 9-speed cassette or a 10-speed cassette, but in the last position, it doesn't matter ...

 

• the cost of separate Miche cogs varies ... more than $10US & should be (?) less than $25US.
• Miche makes cogs which are Shimano-compatble. too

 

And, being an infidel, 'I' would consider using the 29t Miche cog on an 11-speed cassette, too, if I ever wanted the wussy stack on an 11-speed Camapgnolo cassette.

 

As noted above, the ramping on the 11-speed Campagnolo cogs more closely resembles (at least, IMO) the superior ramping typically found on Shmano cogs than what you see on the 10-speed Campagnolo cassettes that I have.

 

 

IMO, if you locate the shifters on the handlebars with your hands in the Drops in mind, then it is equally "natural" in both positions ...

 

• with an older (close to being in need of a rebuild) pair of shifters, I can actuate the thumb shifter with a tap of my ring finger when hands are on the cross bar ... people with slighty stronger hands can certainly do so with on out-of-the box shifters ... so, there are really THREE hand positons that a rider can use with Campanolo shifters.

 

BTW.  I did not mention swapping out your shifters for Campagnolo shifters because there are some people who have become overly defensive about the capabilities of their Shimano shifters ...

 

Plus, choosing the inner chaining which allows you to simply upshift with an 11t as the final cog instead of 12t seemed like another alternative which you-or-others might prefer to investigate.

 

I was not suggesting that anyone shift chainrings during a sprint ... THAT is how what the OP originally wrote read to me ... of course, it could have been (or, be) a comprehension problem on my part ... 

 

• we obviously read what he wrote differently ...

 

BUT, that is why I suggested he change the size of his inner chainring & smallest cog to avoid shifting to the outer chainring because the throw of the inner paddle isn't excessive (but, more than the throw of Campagnolo's thumb shifter).

BTW.  Didn't you stop using those 8-speed 105 "brifters" which you had in favor of bar ends? 

 

• It can't have been for the weight saving because the combined weight of the Shimano brake levers + Shimano bar ends was in the 450 gram range.