Rotor calls their top level elliptical chainrings Qarbon, as an impossible to pronounce contraction of Q-ring and carbon fiber. Basically they are just the same ovalized ring shape and tooth profiles, but incorporating a solid carbon outer plate that both improves stiffness by about 20% while making them more slippery in the wind. Since the non-round rings typically lead to a bit more finicky front derailleur setup, the improved stiffness is a big deal for competitive riders looking for the benefits of the improved pedaling and power output efficiency. Well by popular demand (both from sponsored riders and customers), Rotor has expanded the Qarbon line-up to include offerings to fit Shimano’s newer generation of 4-bolt cranks, as well as noQ (ie. round) rings that get the same stiffness and aero benefits.
Then at an entirely different speed of travel, Rotor has taken advantage of their in-house aluminum machining capabilities to develop a gravel-specific, low-geared, one-piece double chainring. Not limited by the typical compact 110 bolt circle diameter, the forthcoming Spidering will be a direct mount option to their cranksets giving a hill-climbing 46/30 tooth gear combo. Take a closer look below the fold…
Qarbon
Besides improving shifting with increased stiffness, and aerodynamics with a smooth outer carbon profile, the Qarbon rings also drop a few grams since Rotor is able to more aggressively machine the rings. Now offered for Shimano’s recent 110 x 4-bolt BCD, Rotor build in 3 positions to dial in the oval ring alignment per their Optimum Chainring Positions (OCP) system to gets the most out of the rings based on your pedaling style. That’s less than the 5 OCP positions of their regular Q-rings, but Rotor says that these still allow an ideal setup for the vast majority of riders and was necessary due to the shape of the 4-bolt standard.
The addition of standard round noQ Qarbon rings should also please Rotor-sponsored riders, as well as those looking for an alt aero ring, or even just a stiffer big ring for a 110BCD crankset. All of the Qarbon chainrings are available in 50, 52 & 53 tooth profiles in the standard & Shimano 110 BCDs.
Spidering
Then to satisfy the growing gravel crowd who have often been looking for lower than compact gearing comes a new one-piece direct mount double chainring. To be offered in a 46/30 tooth size, the new Spidering is machined from a single chunk of 7075 aluminum and will fit to Rotor’s 3D+, 3D & Flow cranks, as well as their INpower analogues. Besides giving lower gearing, Rotor also told us another driver was the number of gravel frames that had more limited clearance around the chainstays even for a standard 50/34 compact.
That gearing is more than 10% smaller than what you can typically fit on a 110BCD compact cranks so should make for a good option for more drop bar off-road riding, whether it is for gravel racing, singletrack, or adventure bikepacking. The 144g combined chainring is designed for a standard 43.5mm chainline, and will work with either 10 or 11 speed drivetrain setups. Look to see the rings spec’d on some gravel bikes looking to offer a bit more range than what you get with a SRAM 1x setup soon.
