Full Speed Ahead’s SL-K line is one step down from its pro level K-Force range, and over recent years it’s benefited from the technological advances of its higher priced sibling. The new 2011 version features similar hollow construction carbon fibre arms, reinforced with glass fibre to increase stiffness, the deep, highly machined 7075 aluminium chainrings add further beefiness, and it’s all tied together with an oversized (24mm) chromoly axle.
Against comparatively priced chainsets, the 744g SL-K (including BB, and with 175mm arms) beats all but Shimano’s aluminium Dura-Ace chainset on the scales. Most of the weight lost over previous SL-K designs is down to the hollow arms. The outer carbon shape is structural and is reinforced through the whole length with an I-beam. This means the SL-K can be made in one piece, with no internal skeleton or need for bonding two halves together.
The wide, flat shape of the crank arms mean heel clearance is very good, so they’ve stayed clean and scuff-free despite many hundreds of miles’ use. The new larger graphics look slicker than most at this price and they will stay that way for longer. FSA has applied them underneath the final resin coating, so they’re scratch-proof and peel-proof.
There was no discernible flex or creaks or groans under load – in terms of stiffness they’re about the same as Campagnolo’s equivalent carbon cranks; it’s not quite the rock solid feel of Dura-Ace or Deda’s Lokomotiv, but those are the stiffest we’ve ever tried.
Shifting on the highly machined and profiled 50/34 rings is smooth and quick (53/39 with 130mm bcd is also available), and actually improved the performance of our SRAM-equipped test bike. The included MegaExo bottom bracket is excellent quality, makes it simple to fit, and has proven very smooth running. If you’re in the market for a compact chainset we’d highly recommend you give this great carbon model a spin. It’s available with four different arm lengths: 165, 170, 172.5 and 175mm.