There's a common misconception that the lightest bikes or components will always be carbon fibre, and much of the time it will be true, but what really counts is how the material is used. As one of the pioneers of lightweight aluminium manufacturing, Cannondale have 20 years of metal manipulating experience to draw on.
It's long been known that an oversized, hollow aluminium component can be stiffer and lighter than regular size components, and over the years various methods have been employed to create hollow parts. For the SiSL2, Cannondale make each crank in two halves. The CNC machining process removes more metal than has previously been possible, and the two parts are bonded together, creating a super light, stiff component.
Rather than requiring cranks with differing bolt circle diameters (BCDs) for standard double or compact sized rings, the SiSL2 has a central splined fitting for the interchangeable one-piece SpideRing, currently available in 53/39 or 50/34 and 10- or 11-speed compatible options.
The intricate 10-arm spider is 3D forged, then machined from a single piece of aluminium in a design influenced by automotive race wheels. Eliminating the chainring bolts prevents ring deflection when shifting and sheds weight, but the downside is that if one ring wears out, you'll have to replace both.
One of the most impressive parts of the package is the hidden hollow BB axle – 67g of beautifully machined aluminium with tapered splines to accept the cranks – and crank bolts and washers that only add 13g. Unfortunately your £630 only gets you the cranks, SpideRing, crank bolts and lockring. A bottom bracket, bearings, axle and shims cost an extra £169.99.
At just 448g, our 53/39 175mm crank is lighter than top carbon offerings, and has been running faultlessly with Campagnolo Record, the inbuilt shift ramps and pins keeping everything slick. In combination with a press-fit BB30 bottom bracket and SuperSix Evo frameset, it offers great levels of stiffness and performance, proving more than a match for every maximal effort or sudden acceleration.
It's hard to justify the price, or how much difference the average rider might notice, but innovation that works this well is never cheap.
This article was originally published in Cycling Plus magazine, available on Apple Newsstand and Zinio.
via BikeRadar.com http://www.bikeradar.com/road/gear/category/components/chainset/chainset-road/product/review-cannondale-sisl2-hollowgram-chainset-13-47782/?CPN=RSS&SOURCE=BRGENHOME
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