Cassette compatibility

[nscrbug]

Hmmm...interesting. But I think this compatibility issue is limited to the Ultegra 6700 11-28t cassette. I'm sure if I bought an 11-28t 6600, there would be no issues. But I figured, with the 6700 offered at a such a great price ($59 at Nashbar)...I would just go with that. So I guess my specific question is...is anyone running a 6700 11-28t cassette with a 6600 RD?

[redrhodie]

Hmmm...interesting. But I think this compatibility issue is limited to the Ultegra 6700 11-28t cassette. I'm sure if I bought an 11-28t 6600, there would be no issues. But I figured, with the 6700 offered at a such a great price ($59 at Nashbar)...I would just go with that. So I guess my specific question is...is anyone running a 6700 11-28t cassette with a 6600 RD?

I just got the 11-28T 6700 cassette a couple of weeks ago, and I'm using it with an Ultegra long cage derailleur from 2007 (not sure if it's 6600, though--can't find a model # on it, but it's definitely not a 6700). It works just fine. I've done a few hilly rides, and haven't had to have it adjusted yet.

[nscrbug]

I just got the 11-28T 6700 cassette a couple of weeks ago, and I'm using it with an Ultegra long cage derailleur from 2007 (not sure if it's 6600, though--can't find a model # on it, but it's definitely not a 6700). It works just fine. I've done a few hilly rides, and haven't had to have it adjusted yet.

Well...this is good news to hear! And I just realized that in my last post, I stated that I could just buy an 11-28t 6600 cassette - ummm, no such animal exists, so my apologies for incorrectly stating that. Looks like I will have to investigate this matter a bit further.

I'm fairly certain that I need a different RD in order to get this to work...because based on what I've been told by 2 different LBS's, my stock Ultegra SL 6600 rear derailleur does not have enough range to accommodate a 28 tooth (or even a 27 tooth) cog...I was told that I am "maxed out" on my RD with my current 12-25 cassette. And since I definitely need a new cassette (mine is worn - new chain is skipping)...I need to figure out what to do ASAP.

[DebW]

Is your crankset double or triple, and how many teeth in each ring? A RD has a maximum cassette cog it can handle as well as a maximum tooth difference (add differences in cassette large-small and chainring large-small). Tooth difference defines the amount of chain that the RD can wrap up.

[nscrbug]

Is your crankset double or triple, and how many teeth in each ring? A RD has a maximum cassette cog it can handle as well as a maximum tooth difference (add differences in cassette large-small and chainring large-small). Tooth difference defines the amount of chain that the RD can wrap up.

It's a compact 50/34. Yes, I was basically told the same thing by a LBS...that my current 6600 SL RD is maxed out with my current 12-25 cassette...so it would not be able to accommodate a 27t or 28t cog. However...when I do the formula you provided above, I get a maximum difference of 29...so now I'm confused...

[aicabsolut]

The Ultegra RD will probably work. A Dura-Ace 7800 RD will not work well with the 11-28 spread, but for some reason the 105 and ultegra ss RD are a bit more friendly to larger gear spreads with a compact. However, your chain might be a bit short now...

[lo123]

It's a compact 50/34. Yes, I was basically told the same thing by a LBS...that my current 6600 SL RD is maxed out with my current 12-25 cassette...so it would not be able to accommodate a 27t or 28t cog. However...when I do the formula you provided above, I get a maximum difference of 29...so now I'm confused...

My LBS said it'll work and that's Ultegra 6600 SL with compact crankset. And it does work. Actually, LBS owner, a female(!), has the same setup on her Madone 6.2

Like I said, it does need more frequent tuning, but I'm learning how to do that myself and hubby does it for me now, so I don't have to go to the LBS.

[nscrbug]

Thanks to everyone for the advice!!! I've decided to go with the 6600 12-27 cassette...which should work with my current 6600 RD...or so I was told by yet another LBS that I stopped in at over the weekend. So now I'm just shopping around for a good price on one. Oh...and I was told that I'd likely need to replace the chain (even though it only has 300 miles on it) since it probably wouldn't fit with the wider tooth range on the new cassette.