August 31st, 2009 by 
Brian Mullin
Bottom Line
After many months of use, and many miles of abuse, the X10SL has been worn faster than the X9SL, but both have lasted significantly longer than their predecessors. KMC has improved the SL series’ technology to increase the life of the chain, which is an excellent accomplishment when dealing with a lightweight chain in such a demanding and inhospitable environment.
The KMC SL chains are lightweight, shift well and have a usefulness duration that is better or comparable to other lightweight chains on the market. I still would get an occasional ghost shift, but it was nothing that created undue functionality. The technology and innovation that KMC has used for the SL series chain will keep them at the forefront of the chain world.
KMC continues to tweak and massage their chains using their expertise, so they are always upgrading the XSL series so that they can bring the best and highest performing chain to the marketplace.
And of course the gold version is bling, and really seems to shift better!
Strengths
-Lightweight
-Shifting
-MissingLink
Weaknesses
-Durability
-Ghost shifts
Value Rating: 3.5 Flamin’ Chili Peppers 
Overall Rating: 4 Flamin’ Chili Peppers 
KMC SL Series Specs
Colors - gold or silver
Speeds - 9 or 10 speed
MSRP:
9 speed silver - $70
9 speed gold - $75
10 speed silver - $80
10 speed gold - $85
KMC US url: http://www.kmcchain.us/
KMC url: http://www.kmcchain.com/index.php?ln=en
August 31st, 2009 at 8:24 am
‘Chain stretch’ is a figure of speech; I don’t know why people like to be so pedantic about it.
August 31st, 2009 at 10:20 am
I’m curious how the 9-speed version holds up against Shimano’s HG93 (XT) and CN7701 (XTR), durability-wise.
August 31st, 2009 at 8:28 pm
I used one of these last year, and it was the shortest lived chain I’ve ever owned. I would even go so far as to call it junk. You get what you pay for. I’m running the hollow pin/ punched plate Wippermans now, and they are far superior.
August 31st, 2009 at 9:42 pm
They are much improved from last year, but I have not tested a Wipperman, so I can’t compare durability. I will speak with them at Interbike about doing a test.
September 1st, 2009 at 8:48 am
I am 220lbs and run this chain on 4 mtbs. I have been running them for about 3 years and have never had a failure of any kind.
Light AND strong.
November 13th, 2009 at 1:47 am
I can’t say much for KMC’s chains on geared applications, but 7 years down the road my XD series bmx chain has held up through off and on use as college transportation after the bikes glory years. Still can see the gold ti-nitride coating on the pins! (Todays coatings much shinier and blingier)
-but definitely needs to go now, finally started popping off… very reliable and they have been AROUND