Hello All,

I am new to biking. I bought a nice, used bike a month ago. I realize that the chain is worn out and needs to be replaced.

The situation on my bike is a bit odd. The complete chainset is a 10 speed Shimano Ultegra setup, except for the cassette, which is an Ultegra 9 speed.

I do not want to replace the cassette yet (unless you guys strongly suggest I do; it will be another expense) but need a new chain.

My question is: Should I choose a 9-speed Ultegra chain or a 10-speed one?

Thanks

Sandeep

Well that's not going to work all that well. Shifters and cassettes need to match or the shifting is dodgy. You are likely shifting 2 gears in places or you are clattering because the derailer isn't in the proper position. Either way, you need to match the shifter to the cassette. That means getting a new shifter...pricey...or getting a new cassette...less so. Then get the proper chain (a 10 speed).

That's not going to work well at all. A 10-speed shifter, paired to a 10-speed derailleur, will move the chain over the exact distance from cog to cog on a 10-speed cassette.

The cogs on a 10-speed Shimano cassette are 3.95 mm apart. Cogs on a 9-speed cassette are spaced at 4.34 mm. It's not even close to matching, so shifting won't work well at all.

If you've got 10-speed shifters and derailleurs, you really need to replace the cassette. It doesn't have to be an expensive Ultegra cassette, though. Any Shimano-compatible cassette will do, so long as its gearing range doesn't exceed what your derailleurs can handle. Shimano, SRAM, Microshift, SunRace, Nashbar...

After replacing the cassette, be sure to adjust the rear derailleur.

Plagiarizer! Plagiarizer!

Ok. I hear you.

Thanks for the replies.

Now to the next question. I see 6600 and 6700 10 speed cassettes. What I read online suggests there is no noticeable difference between the two, but for me, there is a 30% price difference.

Do you have any preference for 6600 or 6700? Also, what chains will go with these cassettes?

I agree with the others to just get the 10-speed cassette and chain. The Ultrgra 10-speed cassette is only around $46 or so from wiggle.com for example:

wiggle.com | Shimano Ultegra 6700 10 Speed Cassette | Cassettes And Freewheels

So not all that expensive for what it is. For the chain, I usually buy KMC X10 which should also be fairly cheap ($20 to $30):

Search results for kmc x10

I think I bought the X10-93 last time if I recall...

No real performance difference. As you go up the line of Shimano model numbers they tend to make the cassettes lighter by using some aluminum for the cog carriers and different finish on the steel etc. Dura Ace tends to use more exotic metals and construction and some models can be LESS durable but always more $$. Durability and performance wise there is no difference from at least Tiagra-Ultegra in my experience. 6600 or 6700 just buy the cheapest, basically the same thing although 6600 offered some more gearing options which you may or may not need. If you're OK with using something imperceptibly heavier go with the Tiagra or 105 for less $$.

Either will work. It's unimportant which you choose, so long as you get a cassette with the gearing range you want. For that matter, you don't have to stick to Ultegra if price is a concern. Any Shimano or Shimano-compatible 10-speed cassette will work as long as the gearing range doesn't exceed what your derailleurs can handle. Shimano Tiagra 10-speed cassettes can be found for less than $25 and they'll work just like an Ultegra cassette. They're just a bit heavier.

I'm going to suggest you carefully check your component model numbers and/or count everything again. I can't imagine why someone would sell you a "nice" bike with a mismatch as you described.

One question: We have all been assuming your shifters are 10-speed but your OP only talked about the "chainset" being 10-speed. Do you really have 10-speed shifters or are they 9-speed to match your current cassette? If they are 9-speed, the 10-speed chains will work ok with them but, as a rule replace the cassette if you get a new chain to avoid skipping on a worn cassette. You can use a 10-speed chain with a 9-speed cassette also.

Now, with regards to the above question. As noted, either will work well and, if you happen to have a triple crank, get the 6600. The 6700 is supposed to be limited to double cranks although no one, including Shimano's tech service, can tell me why.

Also, the 6700 is "directional" and is supposed to be installed in a preferred orientation. The 6600 doesn't care.

BTW, the 105 level CN-5600/5700 chains are also very good and a bit lest costly. Consider KMC's 10-speed chains which are equally good and come with a master link that eases installation and removal.

I agree 100% with this before you go off buying the wrong cassette. The OP says he bought the bike a month ago, and now needs a new chain. What is it that leads the OP to think he needs a new chain? Have you measured it and its "stretched" (i.e., worn)? Does the chain seem to skip gears, which could be indicative of a mismatch between the brifter being 10 speeds rear and the cassette being 9 speeds. Something doesn't seem right; I would check the part number on the brifter to see if it is 9 speed (ST-6500) or 10 speed (ST-6600 or ST-6700).

^^^ Great points above to double check the brifters. I also assumed that you have 6600 or 6700 brifters. If not, then you will need to stay with the 9-speed cassette.

6600 shifter:



6700 shifter:

Easy way to tell if you have a 9-speed Ultegra brifter is the shifter cable comes out the side. 10-speed were when Shimano went to both cables being routed under the handlebar tape.

ST-6500.jpg

No, both 5600 and 6600 were 10 speed with side exiting shift cables, 5700 and 6700 were both 10 speed with rear exiting cables.

Thanks for the correction - wondered why Shimano had "updated" the 10 speed brifters. The picture of the ST-6700 does not clearly show that the shifter cable exits the side of the brifter; have to look closely to see the "bump" where the housing terminates.

Here is a picture I posted yesterday for another thread, my 6700 equipped bike. Both the 5600 and 6600 are side exiting. I think Shimano is now doing rear exiting all the way down to 9 speed Sora. I like the looks of rear exiting but I still like the functioning of my old MicroShift brifters better than the Ultegra.