17 Jul 2017
Afterburner: The Futureproofed MTB Crank
The benefits of a crank upgrade are obvious: stiffer construction for increased pedaling efficiency, lower weight for boosted acceleration and – in the case of the Afterburner – seriously good looks.
On the other hand, it’s quite a commitment. Should you go for a double or single chainring? What gearing is right for your bike? With 10 and 11-speed rear cassettes common, 12-speed gaining ground, and two different wheelsizes available, it’s not easy to know what you want now – let alone what your riding will need next year.
That’s where the Afterburner’s modular design wins. It ditches the traditional idea of a one-piece driveside arm and spider, because that locks cranks into a certain Bolt Circle Diameter (BCD), limiting chainring choice.
The BCD is an imaginary circle that runs through the centers of the chainring bolts. It’s used to describe which rings fit your spider – the radial arms to which the rings bolt. Smaller spiders have been vital in making single-ring drivetrains work.
The Afterburner works as either a dedicated single-ring crank or a double. Its modular design allows the spider – with its popular 96mm BCD for excellent compatibility – to be removed. Direct Mount (DM) rings then fit straight on, in sizes way smaller than a traditional spider allows. Narrow-wide MegaTooth rings, for instance, are available in 26T – and all the way up to 38T.
Singles have more fun
The benefits of single-ring are many. The crank is lighter (the Afterburner is just 716g) and ditching the shifter, mech, granny ring and cabling can easily remove another 400g. It also frees up bar space for dropper post or suspension remotes, while MegaTooth //product and feature links// hugely increases chain security without the weight or friction losses of a chain device.
For trail riding, a wide-range 11 or 12-speed cassette with a single front ring is ideal.
The Afterburner is available off the shelf in 1x configuration, in two crank lengths (170mm and 175mm), with a 32T Direct Mount ring. It’s compatible with 10/11/12 speed systems. It’s also available as a 10/11-speed double, in a further three gearing options, if your riding is more XC-orientated and demands more ratios.
The cranks themselves are more than up to either task. Hollow-forged aluminum arms keep weight low and strength high, while clever design eliminates the pinch-bolt – and its weak point – on the non-driveside arm. The 24mm hollow axle is chromoly steel for strength, as are the chainring bolts.
The all-important spider is forged and then CNC machined from aluminum, while chainrings are high-spec 7075 alloy – the outers CNC machined, the inners stamped. Precision is as important as strength.
The whole thing is then wrapped up in a beautifully low-key, hardwearing matt/gloss black combo, with laser-etched logos to survive the worst conditions. Best of all, if you change your mind about your gearing choices, your investment is safe: the Afterburner does what any successful design does. It adapts, survives and prospers.