This is the R-Series from Bristol firm Arrox Cycles; it’s an all-new aero road bike from some very interesting people and, thanks to a direct-sale model, its priced competitively amongst the high-end road bike market with complete builds starting at £2,199.
Arrox Cycles was founded when several Bristol-based aerospace engineers and automotive designers began to work together towards a common goal - to create the most efficient road bike out there.
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The Arrox R-Series frame incorporates several unique features that the company is keen to make a noise about; most are aerodynamic details while others are used to optimise stiffness/strength values or improve the frame’s practicality.
Shoulder blades, top fins, tendons and more
Let’s talk a little more about the aerodynamic highlights of the carbon frame and fork of the R-Series. The fork itself gets what Arrox calls a ‘shoulder blade’, which is basically a large aerofoil section that integrates neatly into a sculpted section of the frame’s downtube.
To maximise stiffness, the top tube of the frame also carries a distinctive profile that Arrox refers to as its ‘top fin’. A large, integrated aero seat post is secured in the frame using a single titanium bolt. Beneath the seat post there’s a special guard built into the frame, this prevents its integral clamp from getting jammed inside the tube.
Ahead of the seat tube itself is a gusset-like structure that Arrox refers to as the ‘tendon’. According to Arrox engineers, this structure acts similarly to shear webs used in an aircraft wing, and produces desired characteristics in both lateral stiffness and comfort.
Behind the seat tube is another part inspired by aerospace design, the tail section, which Arrox says increases stiffness at the seat tube area as well as reducing the risk of fracturing the frame through over tightening of its seatpost clamp.
High stiffness-to-weight, for an aero bike
All of these tweaks have amounted to a frame that Arrox says offers an ‘unbeatable stiffness-to-weight ratio’. Well, they would say that.. But in Arrox' own tests, which pitch the frame against reference data from tests conducted by German publication Tour Magazin, the Arrox’s frame and fork scores ahead of seven popular bikes in the aero road category for its stiffness-to-weight ratio.
Arrox's in-house testing concludes that this frame outperformed competitors including the Cervelo S5, Specialized S-Works Venge and Look’s 795 Aerolight. More details from that test can be viewed on the Arrox website.
The Arrox R-Series is sold in three build kits, with a choice of Shimano’s 105 (£2,199), Ultegra (£2,599) or Dura-Ace (£3,299) groups. Interestingly, aside from the aforementioned, all three specs get identical finishing kit, including own-brand 50mm carbon clincher wheels with 23c Vittoria Zaffiro Pro Slick tyres and Arrox’s own fully integrated carbon aerobar, there’s also a Fizik Antares R5 saddle.
Each R-Series bike is available in six sizes ranging from 50-60cm. The R-series frame is also sold as a frameset for £1,699 while the carbon clincher wheels are also sold separately for £1,190. Our size medium (54cm) test bike tipped the BikeRadar scales at 7.04kg/15.52lbs, a fair chunk over the claimed weight figure of 6.5kg/14.33lbs.
We’ve handed this bike over to our tester Matthew Allen, so stay tuned for a full review here at BikeRadar.