The Truvativ HammerSchmidt AM crankset could very well revolutionize bicycle drivetrains from this point forward by eliminating that last bastion of low-tech: the front derailleur. Gone are the days of jammed or dropped chains, missed shifts and bent cages in favour of a seamless and bulletproof system that magically ekes two gears out of a single chainring in any condition, under any load (or even no load), any time you wish.
A system of planetary gears contained within HammerSchmidt's surprisingly compact and thoroughly sealed housing yields an 'Overdrive' 1:1.6 gear ratio. Thus, a 24T ring provides the same range as a 24/38T. All along, the chain is held on tight by the included chain guide and you even gain more ground clearance, too. If you're envisioning downhill security with all-mountain versatility, you're on the right track.
Even better, this wizardry comes with only a modest weight penalty and virtually no increase in Q-factor. At 1623g, a complete HammerSchmidt AM system adds less than 180g to a comparable setup using a Truvativ Stylo two-ring crank and chain guide and is more reliable, tough as nails and way, way cooler.
The Truvativ HammerSchmidt AM Crankset is set up as an ISCG 05 suitable model but comes supplied with the ISCG Old/’03 Seal Disk to allow you to convert this to suit this style of ISCG Frame tabs), and also requires the matching proprietary bottom bracket and trigger shifter.