RULE #85 - Descend Like A Pro

All descents shall be undertaken at speeds commonly regarded as "ludicrous" or "insane" by those less talented. In addition all corners will be traversed in an outside-inside-outside trajectory, with the outer leg extended and the inner leg canted appropriately (but not too far as to replicate a motorcycle racer, for you are not one), to assist in balance and creation of an appealing aesthetic. Brakes are generally not to be employed, but if absolutely necessary, only just prior to the corner.

From Velominati - The Rules

Disc Brakes - The Lightbulb Moment

Its not macho to admit this but I don't particularly enjoy descending...

I know people who dislike climbing and love descending. For me a descent is a means to an end, and its binary. You either crash or you don't.

For instance today on my Instagram feed is a picture of a cyclist who hit a piece of debris whilst descending at speed, went over his bars and landed on his jaw (and only his jaw). Which was fractured in 3 places. These are the sorts of images that give me the willies.

If you think about modern caliper brakes, they have certainly improved but they are a very antiquated design. What other mode of transport can you think of that uses a rubber pad to squeeze against something in the hope of slowing you down? And whilst they work relatively well with aluminium rims, with carbon there's always some kind of compromise, whether in efficiency, noise, wear, or a combination of all three.

Disc brakes have mainly been pushed on the Endurance/Sportive scene - the idea being they work best in wet weather (like the cobbled classics). And they certainly do, but in my opinion its actually in the high mountains where you can descend at 75+ kph that you really see the benefit.

I am recently back from the Pyrenees and its the first time I have ridden disc brakes in the high mountains. Descending was a revelation.

This was my lightbulb moment... Disc brakes - I get it.

Discs have always had a performance advantage over rim brakes for heavy descending, but heat build-up could still be an issue, just in a different way.

Whilst a rim might overheat causing a tyre to pop off (I still cringe remembering Joseba Beloki in the 2003 Tour), or a causing a carbon rim to delaminate - discs aren't quite as dramatic.

But what can happen is "brake fade", where the heat build up causes the pads to become less efficient, and leading to "squeaky bum time" when you get to the next corner.

Modern rotors are finned for additional heat dissipation, making brake fade a thing of the past.

Features Ed. Dave Arthur told me he does not necessarily descend quicker on discs, but he feels much safer. He is a better descender than me though, and in my case I was certainly quicker on disc brakes.

Coming off the Peyresourde I had time to eat a baguette at the summit (that I had climbed up with in my back pocket - how laissez faire is that!) and still catch and overtake a local rider on the descent. For me that's truly unheard of!

The ability to go at full speed aiming straight at the corner and then pull hard and turn in - and to do again and again without fade - is truly hypnotic. You feel like a race car with carbon ceramic brakes.

The irony is Pros will benefit from discs less than most of us… they are naturally better bike handlers, more fearless (and, of course, riding on closed roads).

Rim brakes are a double whammy for less talented descenders - if you are a cautious descender you will likely grab your brakes a lot on a descent, and by doing so you will over heat the rim and potentially cause a catastrophic inner tube puncture. Because disc brakes stop better you grab the brakes less, and because discs don't brake on the rim, the rim does not overheat.

Road bike hydraulic disc systems have come on in leaps and bounds in recent years. They're now so sleek and well integrated that it's hard to spot the difference from conventional shifter levers, despite the added internals.

Pictured here are Shimano's latest Dura-Ace 9170 hydraulic shifters, as seen on the current range of race-ready bikes, together with their compact, efficient flat-mount calipers.

Flat mount (as opposed to post-mount) calipers bolt directly onto the frame/forks; neater, more aero, and more compact (it means the back brake can often be tucked inside the rear triangle, for added rigidity, which means better performance).

I think the potential for 25mm and 28mm tyres and disc brakes to completely transform the overall riding experience is hugely exciting. The last 5 years have seen some real changes...

The first disc road bikes were very much caliper frame designs with discs added in almost as an afterthough. And the first generation of Shimano disc was not that great; finicky, hard to adjust and a bit temperamental (not qualities you want in a brake).

The latest version of the top bikes (Emonda, Tarmac, Altum, R5, etc) were designed very much as both caliper and disc brakes together; and the latest Shimano disc technology is amazing.

But the frame designs have to have compromises to be both caliper and disc ready. The really exciting thing will be the third generation of disc bikes, designed to be disc only, and that singular focus will undoubtedly bring on new developments.

Something like the 3T Strada is the start of this race - a bike that throws out the "legacy" rulebook and is designed from the ground up for disc brakes. Yes it's an aero road bike, but with internal cable routing, thru-axles, wedge seatclamp, and disc-only. Optimised for strength where it's needed most and lightness where it isn't.

below: 3T's Strada aero road frameset - freed from the contstraints of rim brake mounts, the design can be optimised for aerodynamics, strength and comfort:

3T Strada - Flat-mount forks

and a very tidy rear end

Disc Brakes - the talking points:

  • No need to run carbon rims only in the summer. Without needing to worry about brake track damage from winter grit, you can run carbon wheels all year, getting more value from them.
  • We sometimes see a crazy situation where people buy expensive, high-performance carbon wheels for 95% of their riding, but for Euro A races and travel they take Alu clinchers.
  • No more taking two sets of wheels to the Étape or Marmotte, just in case it rains….

What I can say from all the training sessions I did already in training camps now is that it's a very strong improvement. It improves a lot of your steering of your bike, you can handle it really well - so I think it's a good choice... once you are in a downhill there's an incredible difference between rim brakes and discs when it's wet.

- Marcel Kittel

Whatever your thoughts on disc brakes, there's no doubt they're here to stay. We've definitely reached a tipping point in disc technology, and whilst they'll continue to improve incrementally the latest discs do everything we could ask of them; stopping power, reliability and ease of setup.

Stay tuned for the latest developments as we see the new wave of disc-only designed framesets come to market - we'll be following closely here on the blog, and of course in the Build Gallery.

And if you want to get hold of a disc bike of your own, have any questions, or simply want to discuss the options - get in touch.