Ultegra 6700 cassette ratios

markshaw77

I am in the process of upgrading my best bike from 5600-series 105 (in black) to the new 6700-series Ultegra and am being forced into a change of cassette ratio, so looking for advice

I have always ridden with a 50/34 compact up front (new Ultegra will be the same) and a 12-27 at the back, but the new 6700-series Ultegra doesn't offer a 12-27, so I am left with either a 12-25 or 11-28 - how big is the difference going to be? Which one is the better bet?

Now, i used to have an 11-28 on my old 9-speed bike and while it was great for getting up the hills, the jumps between gears in the middle of the cassette always irritated me - does the 10-speed have the same "gaps" and will they be as noticeable?

The 12-25 is the same sprockets as the old 12-27 until the last two (23/25 instead of 24/27) - this seems like the best option to me (along wth a dose of MTFU for the hills) as it will be the same for most of my riding.

Alternatively, i could just leave the 12-27 I have on there, but that will need changing eventually and Shimano suggest that the new 6700 works best when all the components are the same

What to do? Thoughts appreciated...

PeterBL

If your 27 gets you up the hills, and you don't need an 11, I would stay with 12-27. The jump from 17 to 15 on a 11-28 would irritate me.

You can use your current 12-27 until its worn out, but Shimano still makes them in the 105 groupset (5700). You could possibly also find some 6600 12-27 cassettes, if you'd prefer that.

I'm sure shifting will be just fine, even though Shimano of course would want you to run with a complete groupset.

ride_whenever

Could you build your own cassette out of both of them? Are they riveted, bolted or one piece?

tonye_n

I sort of had the same problem.
Moved the Ultegra SL group(with 12-27 cassette) from my carbon bike to my winter bike. Then installed 6700(11-28) cassette on the carbon bike.

The main differences in use for me:
I find the jumps b/w the bigger cogs a quite irritating in use. I could just about live with the 12-27 after using 11-25 for many years when I had standard double. Living in hilly Bristol I use the full range of the cassette quite often b/w both chain rings, and I found the 11-28 just had two many big jumps that it sort of defeated the purpose of having 10 speed cassette.

On the 6600 groupo I often find that the chain rubs on the outer(big) chain ring when I am in some of the bigger cogs. This issue has all but disappeared with the 6700 groupo. the 6700 chain rings may be space a little bit wider I think.

The top of the shifter hoods on the 6700 give a flatter perch. You feel that the shift/brake levers are under your hands when on the hoods, rather than 6600 where you have to reach a little forwards to grab the levers when on the hoods.

tonye_n

Oh,.... and I did remove the 11-28 6700 cassette and replace with a 12-27 6600 cassette. I have not noticed any compromise in shift quality or quietness of the drive train as a result.

markshaw77

Thanks all - that's just the sort of input I wanted

PeterBL - like you , I think the 15-17 jump would really irritate me as the middle of the sprockets is where I am a lot of the time and the smooth moves up and down have been one of the really nice things about moving to the 10-speed (and away from the 11-28)

Tonye_N - thanks for the info - good to hear that the older style cassettes will play nicely with the new mechs, etc

I think I will give the 12-25 a go (been training hard over winter and lost a few Kgs, so might be ok without the 27) and if that doesn't work out, find myself a 5700/6600 12-27 cassette and carry on as normal!