by Brian Mullin on August 31, 2009

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 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 History
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!
I shortened the X9SL (or X10SL) chain to the proper length for my Ibis Mojo drivetrain, with my handy Park CT-3 chain tool. I always suggest you get a good shop strength chain tool, they make chain work extremely easy, and they don’t break. The pin removal was very smooth and easy, and the attachment of the chain on the bike was a breeze using their ‘MissingLink’.

Test bikes: Ibis Mojo and Moots Mooto-XZ 29er
Mojo -> XTR 11/34 & Sram 11/32 cassette, XTR & Race Face Next 22/32/44 cranks
Mooto-XZ -> 11/34 cassette, XTR cranks 22/32/44

The MissingLink is KMC’s proprietary connection system, much like SRAMS’s Powerlink system, which are both vastly easier to use than the Shimano replacement pins. Not sure who actually makes the system (suspect KMC), since they both look suspiciously close to each other? No tools are required to attach the chain together.
I have found the missing link between the higher ape and civilized man: It is we.

MissingLink Installation
Simply insert one half of the link in opposite holes, keep the chain un-tensioned.

1) Insert both halves of the MissingLink into the chain ends.
2) Press both halves of the MissingLink connector together.
3) Lock in place by pulling the chain apart.
4) Opening: press both plates together while sliding the chain ends towards each other.

KMC suggests that you always use a new MissingLink during installation, but I usually reuse them, unless the chain has gotten an inordinate amount of abuse or spent a long time on the drivetrain.
I started out testing the chain in the wintertime, so between the snow, the wet trails, the mud and the wet sandy dirt, the drivetrain usually got trashed pretty quickly. The chain just kept shifting with few issues, except for an occasional small ghost shift, which wasn’t bad considering the treatment and conditions it was dealing with.
Danger, Will Robinson

I was very impressed with the chain, and the initial riding impressions were very nice. The chain shifted smoothly and no matter how difficult and tortuous I was during hard technical pedaling, it shifted like a trooper. After a few rides, I pretty much forgot what I was riding, they just blended into my shifting patterns, rolling up and down the cogs and chainrings as they should. Although the chain has a small amount of lateral flex, it did just fine on the severe cross chain gearing angles (between the cogset and chainrings).

The gold chain looks very sweet with the hollow pins and small slots on the links, and you can really see the engineering that went into the SL chains. The gold is a titanium nitride coating. Its surface is supposed to be harder and smoother and less susceptible to dirt for a longer and more functional life than the regular chains. I will take their word on it, since it would be an extremely difficult test to correlate, for me, I liked the bling factor. However, it did seem to shift better than the normal silver (non titanium nitride coating), maybe I had too many Red Bulls?

Trivia: The precursor to Red Bull was the Thai drink called Krating Daeng (translation: “red water buffalo”).

Measured Specs (116 links):
X10Sl 247.7 grams
X9SL 264.6 grams

The package states it weighs 240 grams for the X10SL and 255 grams for the X10SL, so they seem to be a bit off in their specs. There have been lots of complaints on the weight weenie forum for misrepresenting their weight. Fanaticism!

Technical Features
Careful examination of the chain itself shows some of the technical highlights that the SL chain is engineered with. To save weight, they cut small slots into the plates, and use hollow pins. For shifting performance, they use X-Bridge, in which the outer plate has been configured with specific angles for faster, quieter and smoother gear shifting.They also have StretchProof Treatment (misnomer) for the pins and plates to decrease the invasion of contaminants into the bearings, and therefore increasing durability in harsh environments. High alloy steel is used for the pins and plates, which aids in the reduction of chain elongation for increased chain life. And my favorite is the gold colored Ti-N (titanium nitride) coating, which gives rise to less friction, and lower maintenance, and more bling.

KMC SL Series Technical Specs
-Hollow Pin
-Plate slots
-StretchProof Treatment: exceptional durability
-Outer Plate Chamfering: accurate steering
-Inner Plate Chamfering: expeditious articulating (say what!)
-Mushroomed Riveting: high pin power, inserted with 350 ksi
-Double X Bridge Shape Outer Plate: excellent gear shifting
-Noiseless Function: noise reduction
-Bushingless Construction: smooth transmission
-Ti-N Gold versions: less friction, low maintenance

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!
-MissingLink connector
-Ghost shifts

KMC SL Series Specs
Colors – gold or silver
Speeds – 9 or 10 speed
9 speed silver – $70
9 speed gold – $75
10 speed silver – $80
10 speed gold – $85

{ 1 comment… read it below or add one }

tjdayney October 29, 2009 at 1:46 am

Thank you so much for the input. I am shopping for a new drive system and was worried about the pemature strech issues of this chain. I will give it a try and see how it stacks up against the sram PG 991 hollow pin I've just worn out.


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