Reviewed by Brian Mullin aka Gram and MTBR.com Pastajet
I have been the using KMC SL series of chains for many years now, they are very lightweight, have a plethora of technical features, with good shifting capabilities, and even look good (especially in gold).
I tend to ride with a slow cadence on technical terrain in very small gears, so I cause an enormous amount of torque on the drivetrain system, and especially on the main conduit, the chain. This can wreak havoc fairly quickly on a chain, so I tend to go through them pretty quickly, no matter what brand they are.
I found that with the KMC SL chains, I tended to get premature wear in comparison to other chains. When they finally lengthen beyond their specified limits, they tended to mis-shift, and on occasion I would catastrophically snap a link.
Chains do not stretch, they lengthen (elongate), and they do so because their hinge pins and sleeve hole wear, literally making the chain sloppy and loose.
You can check chain elongation with a chain checker tool (Park CC-2) or measure with a ruler, but both methods can be slightly error prone.
At the 2008 Interbike, I spoke with the KMC staff about the wear issues I was encountering, and they told me they had an upgraded version of the SL series coming out soon that should alleviate that issue.
In November, I started to test out the latest X9SL and X10SL chains on my 9 speed drivetrains, which included an XTR and Sram X.0 system. Although, some people report issues (front shifting?) with using a 10 speed chain on a 9 speed drivetrain, I had never had any shifting issues with that combination, nor have many others on the MTBR.com weight weenie forum. The main reason to go with a 10 speed is to save weight. The KMC SL chains are available in either silver or gold colors, in both a 9 and 10 speed, and are compatible with Shimano, Sram and Campagnolo.
KMC Chains was established in Tainan County , Taiwan in 1977 by Charles Wu. The company makes bicycle chains as their core business, and they also make motorcycle, automotive, garage door opener and industrial chains. In the mid 80′s they partnered with Shimano to supply them with a whole series of their chains. They make over 500 million feet of a chain a year, which is a heck of a lot of chains!