Specialized test the aerodynamic qualities of both disc and rim brakes to see which perform best in the wind tunnel

Rim brakes or disc brakes. It’s the age-old question that divides opinion in the cycling world. Most bike manufacturers would test the relative braking capacities of the two systems, but not Specialized.

>>> The disc brakes debate: are they necessary on road bikes?

In the latest edition of their The Win Tunnel series, the guys at the American company tested the aerodynamic qualities of the setups in their wind tunnel in Morgan Hill, California.

Somewhat unsurprisingly, the technicians discovered that when faced with a head-on wind there was no difference between the two setups – on which the only the brakes, hoods and rims were different.

But when subjected to a side wind the disc brakes turned out to be eight seconds slower over the standard 40km testing distance.

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Eight seconds, however, probably isn’t enough to put anyone off using disc brakes, especially given the seconds they will shave off in the corners.

Specialized say: “If you’re doing any rides with a lot of descending or tight corners, that little bit of extra confidence that the disc brakes will provide may wipe out those 8secs over the 40km. So it’s really the whole package and not just the aero that you have to look at.”

  • adrianoconnor

    “Somewhat unsurprisingly, the technicians discovered that when faced with a head-on wind there was no difference between the two setups”. If that’s true, why do aerodynamic bikes have those crazy reverse-mounted calipers on the back of the fork these days? What’s that all about? Is it just marketing nonsense, because it ‘looks’ aero?

    Also, FWIW, I’d love disc brakes. I ride in all weather, all year round, and I wear out rims like you wouldn’t believe. Also, rim brakes aren’t actually that great in properly heavy rain. If I could afford an N+1 right now, it’d quite possibly have discs.

  • Mark

    I’m confused by both the comment below and the attitude of this article. Would anyone who has ridden disc brakes argue that they are not factually better than rim brakes in “relative braking capacity,” power and modulation? Why would a company test an established fact? Working in a bike shop, I can attest to the fact that the two most common doubts regarding disc brakes on road bikes are assumed aerodynamic disadvantage and assumed weight. I think this video excellently addresses one of those concerns.

  • David Chadderton

    Thank you Specialized for the research and explanation. As I do not race up Mont Ventoux and fight its cross winds, being slowed by disc rotors, then race down the other side in the professional peleton, hoping to outbrake others on the hairpins, I personally do not need ugly disc brakes on my road bike.
    Also, I do not race down mountains in MTB events.
    In fact, I do not like braking at all. It takes away the energy and momentum that I laboured to put into my ride. I try to limit braking to stopping at road junctions, traffic lights, roundabouts and my garage door. Oh, and at the cafe.
    Don’t even mention disc wheels to me, thanks.