SRAM have combined a new carbon-armed downhill crankset, rear derailleur and chain guard with select components from their second-tier X0 'family' to create a new 'X0 DH' groupset aimed at gravity riders.
Said to be the world's first carbon fibre downhill crankset, the Truvativ X0 DH has already seen success at the highest level – it was used by Sam Hill on his World Championship winning race run last year.
Claimed weight is just 765g (with GXP83 bottom bracket, 165mm arms and 36-tooth chainring) thanks to its carbon arms, forged aluminium spider and 7075 T6 alloy pedal inserts. It looks to be based heavily on the standard 2x10 X0 chainset, and features the same arms. But it has a more compact spider, as it's designed to be run with a single ring up front.
According to SRAM's Tyler Morland: "It comes in basically every length and every bottom bracket you could get to fit any type of bike." That means: 170 or 165mm arms; Press Fit 30, BB30, Press Fit GXP, GXP and Press Fit 30 DH bottom brackets, with 73 or 83mm spindles; and a choice of 34, 36 or 38T chainrings (CNC-machined from 7075 alloy).
Prices will start at US$444 (UK pricing TBC), depending on bottom bracket type. Bottom brackets aren't included, and cost from $40. The crankset is compatible with nine- and 10-speed transmissions, and comes with a choice of silver or red graphics.
The short-cage X0 DH rear mech – used by BlackBox testers such as Steve Peat since early 2009 – has been designed to provide fast and precise shifts for the close-ratio cassettes used on downhill, four-cross and jump bikes. To this end, the section between the cage and parallelogram has been shortened.
It weighs just 190g (claimed) thanks to a carbon fibre composite outer cage, forged aluminium inner and titanium hardware, yet has been designed to stand up to the rigours of downhill racing, with sealed bearings for improved durability.
All the usual SRAM rear derailleur features are present, like a 1:1 actuation ratio and direct cable routing. The mech is designed to be used with a 10-speed cassette (up to 28-tooth large cog) and is compatible with any 10-speed Exact Actuation shifter. RRP is £149.99/$234, and it's available with silver or red graphics.
To complement the crankset there's a new Truvativ X0 badged chain guard. Built for SRAM by MRP, it looks nigh-on identical to the latter company's G2 SL guide. It's available in two sizes, 36-40T or 32-36T, weighing 185g and 168g (claimed), respectively.
Features include sealed bearings on the pulleys, easy installation thanks to captive hardware and front-access bolts, and compatibility with BB-Mount, ISCG and ISCG 05 mounting standards. It's available in two colours – black or white. RRP TBC.
The rest of the groupset is existing kit: a 10-speed SRAM X0 right-hand shifter (£119.99; 116g; silver, black or red) and PG1070 cassette (£69.99; 210g), plus Avid X0 brakes (£199.99 per end; 330g front).