FSA SL-K Compact Carbon Crankset
By James Sharp

In 2003 Tyler Hamilton and Carlos Sastre won stages of the Tour de France using compact double cranksets. Tyler had a broken collarbone at the time. Since then, the compact double crankset has been a mainstream part on many new bikes -- and a popular aftermarket item as well. What makes a compact double compact? Normal road cranksets have 130 or 135mm bolt circle diameter. This limits the size of the inner ring to around 39 teeth, most road cranksets run a 53 tooth outer and a 39 tooth inner ring. Compact cranks have a 110 mm bolt circle diameter -- similar to mountain bike cranks -- which allows the use of inner chain rings down to 34 teeth. Most compact doubles have a 50 tooth outer ring and either a 34 or a 36 tooth inner ring. The benefits of this are obvious -- the compact double allows lower gears without resorting to a heavy triple ring crankset or a wider spaced rear cassette. FSA supplied both Tyler and Carlos with their cranks, and recently we’ve had the chance to spend quite a bit of saddle time with the SLK Compact MegaExo crankset.

First off, this is a very nice crank. The arms are compression molded carbon fiber, which means that if you were to cut an arm in half it would be solid all the way through -- it would be a shame to cut into a crank arm that looks this good, though, so please don’t. The drive-side arm and spider are one piece; no chance for creaking here. The SLK uses FSA’s MegaExo two-piece design. As we stated in our review of their K-Force mountain crankset, the MegaExo design provides a very stiff pedaling platform by placing oversize bearings outboard of the bottom bracket shell. In addition to increasing the stiffness, the oversize bearing should last longer and we’ve not had any issues with them in either the road cranks or the mountain cranks. Installation is dirt simple, with torque specs etched into the bottom bracket cups, as well as the direction they rotate to tighten.

On the test bike, the compact double replaced a road triple crankset. Instead of 52-42-30, I now had a 50-34. The most immediate change in my riding was I spent more time in the big ring. I like to spin, I am very comfortable riding at 100 rpm, and so the smaller big ring suited my riding style to a T. If you like a slow cadence then you might find that you run out of gears on faster rides, something that is remedied by running an 11-tooth cog in back. I also found that the 34 tooth inner ring was more than adequate for any hill I threw at it. Consequently, I climbed a little faster since I didn’t have a "bail out" gear. I discovered that I didn’t really need the bail out gear, and was just mentally defeating myself all this time. There are also fewer overlap gears, giving you a wider, more usable spread. Finally, at 840 grams, including the bottom bracket, it’s a little heavier than either Shimano’s Dura-Ace crankset but is on par with their Ultegra offering.

The only issue that I’ve had with the cranks was getting the front derailleur set up right. Once that was out of way, I found ramped and pinned rings to shift without a hitch. Due to the difference in ring sizes, though, I couldn’t use the smallest three cogs in the small ring. Shifting into those caused the chain to rub the big ring. Not a big deal to me at all, because I could use all but the biggest cog while in the 50 tooth ring.

Summary: For $330 you can have a similar crankset as the one used by professional cyclists. It won’t make you as fast as they are, but it can reduce the weight of your bike, make the hills a little more knee friendly and... well... it’s carbon fiber! The FSA chainrings shift well, the combination of external bearings and monocoque construction make for a very stiff pedaling platform and they look great. If you are running a triple crankset or are looking for easier gears for the hills, you owe it to yourself to check out the SLK compact crankset.

James Sharp is a contributing editor for GearReview.com specializing in all things cycling.

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