Ridley calls the Dean time trial frameset “The fastest bike in the world”, and it’s more than just braggadocio. Rather than abiding by standard industry practice, i.e. knock off a Cervélo P3 and spice it up with fancy paint, Ridley spent a small fortune in the wind tunnel to develop a bike that shaves away drag by doing more than incrementally narrowing tube profiles or shortening a head tube.
Rather, they’ve gone to the heart of structural engineering and found answers to questions other companies never thought to ask.
If you geek out on time trials, then you’re no doubt familiar with Oval Concepts’ Jetstream technology. You find it in their $1000+ aero bars, and formerly you found it in their aftermarket carbon forks.
Initially the Dean started out as a collaboration between Ridley and Oval, but eventually it made most sense for Ridley to outright buy to the rights to Jetstream. Once that happened, Ridley aggressively invested in its development and it resulted in the R-Flow design you’ll find in the Dean’s fork legs and seat stays.
As we all know by now, drag increases exponentially with airspeed, which means small changes to reduce your drag will have a disproportionately positive impact on how fast you ride at a given power output. R-Flow technology focuses on one central issue of bicycle aerodynamics: According to Ridley, your wheels produce 8x more drag where they pass through your fork due to the turbulence of the colliding air masses there. The R-Flow fork and seat stays on the Dean minimize this drag thanks to their long, slotted airfoils that direct oncoming air away from the turbulent areas near the wheels.
The slotted design of the Dean’s airfoils addresses the fact that at cycling speeds a single airfoil can’t deflect a large mass of air without creating substantial drag. Not unlike racing catamarans or aircraft landing flaps, slotted airfoils can deflect air without creating drag. The Dean redirects the air stream away from the wheels, and has the added benefit of creating a low-pressure area that further reduces the drag of your rims and spokes.
The story of the Dean goes beyond R-Flow. Ridley used oil mapping in the wind tunnel to isolate spots of turbulent airflow on Dean prototypes. Not only did this technique allow Ridley to re-sculpt the Dean throughout its development, but it had the ultimate benefit of helping them identify key sections of the frameset where they couldn’t re-sculpt the frame due to structural limitations of the frame itself.
In these seemingly unfixable black holes of drag, they apply a textured surface treatment for boundary layer control. Ridley calls it “R-Surface paint”, and our affectionate shorthand here is “aero paint”. These thin stripes of texture are amazing: They purposely trigger a known amount of turbulence that re-energizes lost boundary layers, ultimately re-establishing laminar flow and minimizing drag.
In other words, they carefully create an airflow mess in order to make an unprecedented cleanliness. Airflow control is why you see vortex generators on jets, and why you see dimples on golf balls. And it’s exactly what Ridley does with their R-Surface paint.
One of our favorite details of the Dean is a topic normally swept under the rug when you talk about TT bikes: Weight. The cost of being aero, you’ll normally hear, is added weight. But, thankfully, with the Dean you can ride a TT bike that feels as light as a road bike. A size Medium frame weighs 1360g before you cut down the integrated seat mast to height. The challenge of building a 16lb TT bike is a piece of cake. You’ll be equally fast on any course, dead flat or relentlessly rolling.
The Dean comes in 4 sizes from Extra Small to Large. We strongly suggest that you focus on the virtual top tube length as you make a determination of the proper size. The Dean requires an English bottom bracket, and a braze-on front derailleur. It has a 5-year warranty from manufacturing defect. Its R-Flow monocoque carbon fork is substantially more aero than the one that comes on the Noah, but it nevertheless weighs only 490g. In addition, your frame will come with a headset and an integrated seat clamp that allows you to position your saddle in an effective 76, or 73 degree position. If you’d like to ride it in the 78-degree position, a different clamp is available (you’ll need to purchase it separately) that allows this angle. The standard Dean clamp has 18mm in height adjustment, and comes with a 1mm micro-spacer for small adustments. (Ridley offers an additional aftermarket clamp that provides 40mm of height adjustment.)