Hi,

For a 10 speed Shimano Ultegra SL with a Shimano Ultegra 6600 double crank. Which model chain would be best and which length?

Thank you for any advice,

You can use any 10 speed chain you want - Campy, Shimano , SRAM - take your pick. As for length, you have to adjust that yourself. Chain length must be bike mechanic's most mysterious subject. It's almost a daily thing.

To insure that you get the maximum wrap capacity from your RD, set the length with the chain installed through the RD as normal, in the little ring and smallest cog. Make it as long as possible without hanging loose or rubbing the upper chain guide on the RD cage.

Others will suggest the big/big method, skipping the RD and adding 1 inch to the length when the ends are brought together. Tha works too, but can give ambiguous results when the end that come together can't be joined. Then you add 3 links or 1-1/2 inches. It also suggests the shortest length unless the cassette you're using has the largest cog size the RD can handle.

I read lots of post where someone used the big/big method and needs to lengthen a chain when they want to switch from a 12-23 to a 12-27. The little/little method avoids that problem.

dave,

Thanks for the help.

Big/big-Never again. Never, ever again. Got burned using this method at the shop. My fault for not fully understanding the mechanics of chain length, and blindly going by this method. Wound up with a bent hanger, ruined derailleur, etc.

How did a properly installed chain using the big-big method cause damage? Did you change the cassette for one with a larger large cog afterwards? Was the total tooth count so far beyond the rear derailleurs wrap capacity and you tried little-little and the chain was so slack it caught in something? Otherwise I don't see how it could be damaging.

shimano recomends that the rear deraileur pulleys are in a verticle line when the chain is on the large chainring and the small cog.

At which point you round up.

This is no different than adding one extra link on top of the normal method.

You got burned because you have no idea how to properly size a chain big/big, so it's the methods fault. Massive lulz pls. What mechanic doens't check big/big after a chain install anyways?

Sram recommends big/big.

I test both big/big and small/small and pick whichever method indicates a longer length.

Sram derailleurs by their design (single sprung pivot) are insensitive to chain length as long as it's long enough, but work with a smaller range of cassettes. Campy derailleurs work with a bigger range of cassettes, correspondingly depend more on chain tension to keep the top wheel at the right distance. Shimano are in between.

This is not true.

Sram ROAD derailleurs are VERY sensitive to chain length. The single pivot is NOT sprung. There is zero give.

Big big plus two links has always worked for me. Yet, when in doubt go longer. You can always chop out a link.

The big ring and smallest cog method can be ambiguous too. The RD cage can angle back with the correct length chain, angle forward when it is too short and never position the cage vertical.


Operator...

Your comments are all valid, but if people follow the instructions that most websites or books recommend, they don't tell you what to do if the ends of the chain that come together don't match up. All you ever see or read is to add one inch (or two links) as if the ends that come together will always match.

I've never seen the suggestion to add two inches of chain rather than one, either. That would work with some cassettes, but not all. It would also require a check with the littl/little before use to be sure the chain is not too long. The little/little method is never ambiguous.

vredstein...

You should never get burned by the big/big method unless you removed one inch of chain instead of adding it or if you changed to a cassette with a larger cog and didn't check the length after the cassette change.

There is zero give, therefore the location of the top pulley does not change with chain tension. Therefore it shifts just as well with a minimal length chain as is does with a longer chain. Hence, it is insensitive to chain length.

You may be thinking of what happens if you put on a chain shorter than minimal length, that doesn't fit around big/big. Only an idiot would do that; when considering the impact of chain length on shifting performance it is completely outside consideration.

Also, the cage pivot IS sprung (you know, "single sprung pivot", as opposed to other derailleurs have two sprung pivots). If the pivot were not sprung, it would not be able to take up slack, obviously.

That's unfortunate, but it's common sense that you'd have to round up. There's no other possibility if you think about it for 0.2s.

The little/little method breaks your bike if you exceed chain wrap capacity, unless you also confirm with big/big.

No.

I know exactly what i'm talking about. The rear derailleur has no tolerance for even the slightest incorrect chain length that a shimano derailleurs would've taken up no problem. This is precisely why we didn't warranty a bunch of sram road derailleurs when they were sent back - the derailleur has no give and is thus it is *extremely* important to get the chain length correct -user error. Something that the shimano derailleurs give you more leeway on. It's unfortunate, but too bad.

Go look at the road derailleurs and compare to the shimano ones, where the tab stop is for b-tension.

This is like saying "my microphone is sensitive to being smashed with a hammer." I'm talking about how sensitive the microphone is when used within parameters.

Thanks for the irrelevant post. Do us a favour and stop talking.

It sure does, which means you're stupid. If you're smart enough to know what you're doing, you either choose not to use the big/big or you decide to let the chain hang loose in several of the smallest cogs. Neither situation is a great idea.

Nonetheless, a sram rear derailleur with minimal permissible chain length shifts exactly as well as a sram rear derailleur with chain a link longer. It is insensitive to the variation.

If you smash it with a hammer, by using a chain that is shorter than the minimum permissible, it will break. Some people appear to think this is not an obvious fact.

One situation is a lot worse than the other.