The 6700 is the directional one with supposedly better shifting. But at one point I thought I had read that there were some breakage issues with the 6700 design. The weight difference is close enough to be a non-issue for me.
The 6600 can be had a bit cheaper and that’s the chain that is on my bike now.
Any advice on which way to go, or are both very good performing, strong reliable chains? Any concerns I should be aware of?
I’ve used both chains - 6600 and 6700 - on my road bike set up with Dura Ace cranks (7900) and RD (7800) and SRAM (1070) and Shimano (6600 and 7800) cassettes with good luck. Shifting is spot on and smooth - better with shimano cassettes. The 6700 is maybe a little better shifting, but both chains work well. I’ve also used the 6600 chain on my TT bike with SRAM Red RD, SRAM 1070 casette, and Specialized crankset also with good results. Just make sure you install the pin correctly - read the directions as to which end of the link to pin - Lennard Zinn (velonews) has written about this and the shimano instructions are pretty good. It’s a chain, don’t be concerned with weight.
I was using the 6700 chain on a 7900 group, until yesterday when I snapped the chain starting from a stop. Not a crazy acceleration or anything, just a typical start from a red-light. The chain only had approximately 600 miles on it, and with the ridiculously dry weather we’ve had in Massachusetts this summer, I don’t think it saw one drop of rain. I’m also pretty good about not crosschaining so the failure of the chain was definitely premature. I’ve read a bit online about the 6700 chains breaking and mine definitely failed in the same way as others I’ve seen on the web. I’m not sure if there is a problem with the chains or if the failure rate is normal and people are just hyping it up a bit. I originally bought the 6700 chain because there was a big price difference between that and the 7900, but the prices seem to have come down a bit. Now I’m replacing it with a 7900 chain as it was only $5 more and I haven’t heard of any failure problems with them.
Now that you mention it, PBK has the DA 7801 on for $40 Cdn, less than the 6700, which would seem to bring it into the mix.
I put 3500 miles on a 6600 chain with no issues, so did my GF and several other people I know.
jaretj
Do you know how the chain was installed? That sounds like an installation-related failure to me. Was the pin re-used? What tool was used to install it?
I love 10-speed freewheels, but I don’t like how touchy the chain installation that goes with them is.
I do all my own wrenching and have for about 20 years. I installed the chain myself. It was shortened a few lengths when bought, and put on the bike. I use Wipperman links on all my chains so I didn’t compromise the chain in any way by trying to add links, reusing pins, etc. It failed about 15 or 20 links away from an end, so it wasn’t due to the initial removal of a link. Also, the new Shimano chains have an inside and outside and I had it installed in the proper orientation.
Normally when I read about chain failures, my first reaction is that it is likely installation error. In this case, being my own chain, I know that’s not the case.
Then I’m stumped. Sorry. Sounds like a QA error at the manufacturer to me, then.
My own opinion is that Shimano may have had a batch of bad chains. When you google Ultegra chain failures, you see a bunch of people that are having chains failing due to cracked side plates. This is exactly what happened to mine. I haven’t inspected the rest of the links to see if it was just one link, or if several links are cracked. It seems that all the broken chains people have posted about are failing in the same exact way, and on the same side (the inside) of the chain. Maybe its a manufacturing problem, maybe not.
Not to hijack this thread, but which Wipperman link did you use? Will the standard 10s link work for the 6700 chain?
Thanks.
Richard
That’s what I use.
Victor
I’ve always just used the standard Wipperman link intended for Shimano compatible chains. Never had a problem with shifting performance or reliability yet.