Free 2-Day Shipping on Orders Over $50* — Limited Time Only
Take 10% Off Your Entire Order* »

Out of Stock

Item # RID0036

Don't worry though, we have a lot more Custom Triathlon Bikes & Frames in stock than that.

View Similar Products
Item # RID0036


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 than abiding by standard industry practice, i.e. knock off a Cervélo P3 and spice it up with fancy paint, they've gone to the heart of structural engineering and found answers to questions other companies never thought to ask. Ridley calls their Dean time trial frameset "The fastest bike in the world", and it's more than just braggadocio.

Initially, the Dean started out as a collaborative effort between Ridley and Oval Concepts, as the Belgian bike maker was keen to use Oval's Jetstream technology, but eventually it made sense for Ridley to buy the rights to Jetstream. Once that happened, Ridley aggressively invested in its further development, resulting 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 even small changes to reduce your drag will have a disproportionately positive impact at higher and higher speeds. Though every inch of the Dean is sculpted to cheat the wind, R-Flow technology focuses on one specific issue of bicycle aerodynamics -- according to Ridley, your wheels produce 8x more drag where they pass through your fork and seatstays due to the turbulence of the colliding air masses there. The R-Flow fork and 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.

Ridley Dean DetailThe 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. 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. 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. You'll be equally fast on any course, dead flat or relentlessly rolling.

The Ridley Dean is Black/White and comes in four sizes from X-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. Your frame will come with an integrated headset and a seat clamp assembly that allows you to position your saddle in an effective 75° or 78° position. The standard clamp assembly allows an 18mm range in saddle height and comes with 1mm micro-spacers for small adjustments. (Ridley offers an additional aftermarket clamp that provides 40mm of height adjustment.) One other nice bonus of the Dean is that the frameset includes with a set of Oval Concepts' A700 aero brake calipers.

Please provide us with your BB-Saddle Rail height in the "Comments" section of our order form so we can properly cut down the seat tube for delivery.

One final note on sizing: On all sizes, the top of the uncut seatmast is 235mm above the center of the top tube.

sizing chart

Bike size by rider height


Geometry chart


Geometry Chart



Seat Tube


Effective Top Tube






Head Tube


Head Tube Angle


Seat Tube Angle


XS 71.0cm 52.0cm 49.0cm 40.0cm 9.0cm 72.5o 76.0o
S 74.0cm 54.0cm 50.0cm 41.5cm 10.0cm 73.0o 76.0o
M 77.0cm 56.0cm 52.0cm 43.0cm 12.0cm 73.0o 76.0o
L 88.0cm 58.0cm 53.5cm 44.5cm 13.5cm 73.0o 76.0o

Geometry Chart

Reviews & Community


Write a review

    Add a:
  • Photos
  • Videos

No file chosen

Rather attach a photo from your computer?


Only jpg, jpeg, png, gif or bmp files please.

Submit ReviewCancel
Unanswered Question

I checked the fit guide and with a 33.5...

I checked the fit guide and with a 33.5 inch inseam it said I should have a 56cm bike. How does this compare to the Ridley Dean sizing? It says to use the virtual top tube, but doesn't say how to figure it out. I normally ride a 58cm road bike.