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Ridley Dean Fast TT bike stretches out, finally adds disc brakes

Rider racing on Ridley Dean Fast Disc TT bike
6 Comments

While the prior rim-brake Dean Fast appears to remain in the line as a complete bike option, this all-new Ridley Dean Fast Disc gets a lot of aero updates and (better late than never) switches to disc brakes. And, it will only be sold as a frameset at launch.

Using CFD, they “identified new designs that would minimize drag at speeds around 55km/h”, or about 34.2mph. Yes, that’s wicked fast, but it’s about the average speed of the 10 fastest Tour de France Individual Time Trial performance (according to this website). Which means top riders are often going faster than that, and let’s be honest, bikes like these are made for the top team riders first and just happen to be for sale to the rest of us.

side view of Ridley Dean Fast Disc TT bike

The biggest change comes from taking advantage of the UCI’s new 8:1 length-to-width tube profile rules, allowing for dramatically longer tube proportions than the prior 3:1 rule.

closeup details of Ridley Dean Fast Disc TT bike

Ridley applied this in “compensation triangules”, which is another new allowance from the UCI, giving this bike an extended head tube that creates a blunt point at the front, then runs deep behind the steering axis.

That shape blends into the fork’s crown, and the stem is nestled into the head tube for a further streamlined frontal area, flowing directly into the top tube.

closeup details of Ridley Dean Fast Disc TT bike

Ridley’s other trick, called “F-Surface”, which they’ve applied to other bikes in the past, include dimpled surfaces (similar to a golf ball) and indented grooves at key points on leading edges. Combined, they create smoother laminar airflow, which keeps the air flowing smoothly over and off of the tubes and minimized eddies and swirls that cause drag.

front angle view of Ridley Dean Fast Disc TT bike

Keeping with trends, it fits up to a 700x32mm tires, though it was designed around 700x28s.

closeup details of Ridley Dean Fast Disc TT bike

And it gets a UDH rear hanger, helping future proof it for whatever drivetrains may come.

The front derailleur mount bolts on, letting you remove it for 1x setups to further reduce drag, and two clamps come with the bike – one for normal chainring combos up to 53/40 and one for monsters fitting up to 60/47 combos.

It’s designed for electronic drivetrains only, with no accommodation for mechanical shift cables. The downtube has three bolts creating two bottle mount positions, plus one set on the downtube.

closeup details of Ridley Dean Fast Disc TT bike
closeup details of Ridley Dean Fast Disc TT bike

The included base bar has mounts compatible with most aero extensions and elbow rests, letting you add your favorite setup.

The frame weighs a respectable (for a TT bike) 1,250g in size Medium, with a 460g fork and 341g base bar. Available in S/M/L sizes for $4,999.

Ridley-Bikes.com

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DefRyder
DefRyder
8 months ago

Do these bikes truly make a difference in TT? Pogacar took 2nd on his ‘normal’ Colnago V4Rs at TDF in stage 16.

Last edited 8 months ago by DefRyder
Ashok Captain
Ashok Captain
8 months ago
Reply to  DefRyder

Pretty interesting observation! Cheers.

Exodux
8 months ago
Reply to  DefRyder

True, but there were a lot of climbing on stage 16 which made a dedicated TT bike less effective, although Vinegaard used his TT bike for the whole course and won. Podacar and most others switched from a TT bike to a standard road bike when they hit the climb.

Robin
Robin
8 months ago
Reply to  DefRyder

Absolutely. On a road bike, pros can have a CdA on the order of 0.24-03 m^2. It’s been estimated that Jonas Vingegaard has a CdA on his time trial bike that might be as low as 0.17 m^2. So using the smallest road bike CdA and comparing it to a more conservative value for Vingegaard on his TT bike, 0.18 m^2, means that the drag force on Vingegaard would be 25% less than the guy on the road bike. That’s huge. Even uphill in that TT, Pog was losing time because Vingegaard had to overcome less drag.

Keep in mind that about 75% of the power you apply to the pedals to go at a constant speed just goes to overcome aero drag.

edzoba
edzoba
8 months ago

Why disc in TT? sy please explain

Fake Namerton
Fake Namerton
8 months ago

Outside of being able to swap wheelsets I’ve never understood disc brake TT bikes. I can’t think of a time in the last 20 years racing TTs I had even a modicum of an issue with carbon wheels and rim brakes and I live/race in quite a hilly area. For road racing I get it (albeit never really had an issue with tubulars) but people really aren’t too daring on TT bikes.

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