by Marc Basiliere
September 27, 2013
More than just odd chainrings
For 2014, Spanish component company Rotor has completely revamped their mountain crankeset line, with a new naming scheme, two new arm sets, and drop-stop ‘rings in their trademark ovalised shape. The vast majority of the line is CNC machined by Rotor in Spain and the company was keen to share the fact that their new 1x narrow-wide chainring had won the Marathon World Championships under Christoph Sauser before even being announced to the public.
That chainring, the QX1, uses a Rotor-specific bolt pattern available on both their own cranks and on spiders made for SRAM and Specialized models ($70). Built using the narrow-wide tooth profile we’ve come to know and love, Rotor’s QX1 ‘rings have an effective gearing 12.5% higher at the points that the legs are strongest than where they are least powerful. This more aggressive ovalising (when compared to geared ‘rings) is used to make the most of 1x drivetrains’ limited ratios. Surprisingly, the design results in negligible chain growth (on par with chainstay flex), allowing the rings’ use on singlespeeds and preventing undue wear on clutch-type mechs.
Now unified under one name, all Rotor Rex mountain cranksets feature holes along their length, removing material but not taking stiffness with it. The arms are mated to large 30mm aluminum spindles, which are compatible with every common bottom bracket (when paired with the appropriate Rotor bottom bracket). The company believes in an a la carte purchasing and pricing- cranks, chainrings, and bottom brackets are all sold separately. This, they feel, ensures that riders get only the parts that they need and that no part sits in its box unloved and unused.
Without question a premium product, Rotor starts their line with Rex 3.2 and 3.3 cranksets (the second number referring to chainring count), which are said to be on par with Shimano XTR in terms of weight, rigidity, and price. The double comes in at 544g (plus BB) and $335 for the arms alone. Despite being the company’s entry level offering, the entire Rex 3.x setup is machined by Rotor in Spain. As noted above, double (QX2) and triple (QX3) chainring sets are only 10% taller than they are wide, largely to improve shifting.
Shaving about 35g and gaining a bit of stiffness, the Rex 2.1 and 2.2 (no triple) arms are a forged design carried over from 2013. The QX1 spider can more easily seen on this bare crankset and allows for a wide range of tooth sizes while maximising stiffness. The arms alone come in at $365 for single and $400 for double versions.
At the top of the line sit the Rex 1.1 and 1.2. Once again machined in Spain, the 1.x arms use larger lengthwise holes than the rest of the line and 7055 aluminum to build a 489g crankset (less BB) weight. Rotor are asking $500 for the 1.1, $550 for the 1.2 plus chainrings and bottom bracket.
To complete the cranksets, QX1 chainrings run $125 apiece. A QX2 pair are $250 and QX3 triple sets $290. Bottom brackets run from $30-75 (and much more for ceramic). For those prices, the buyer gets a unique and proven design, Spanish manufacture, and rock-friendly alloy construction. Rotor is distributed in the UK by Velo Tech Services and we’ve put in a request for UK pricing.