Yes, there’s a little tongue in cheek with our title because in a few years our bet is disc brakes in the pro peloton of all disciplines will be the obvious spec we all really know it’s going to be. Just like e-bikes are coming whether you like them or not. So we love seeing some of the biggest and best keepin’ it real. Thanks for posting, JPow!

56 COMMENTS

  1. Cue people who understand neither physics nor cycling trying to bring the “inertia” of a spinning wheel into this. To those people: First look up what inertia actually means, then look at some race crashes, think for a while, and then go ahead and conclude inertia has nothing to do with this.

    • Maybe pedantic, but aren’t you implying inertia has a lot to do with this, just that the rotational inertia of a road wheel in a crash is too low to result in an issue (further…most crashes will have a rider lock up wheels first, or the wheels stop moving due to the crash, so rotational speed will be low and due to the bike falling/getting hit by other objects)

    • It’s not clear what you mean by inertia. Are you talking about the wheel’s moment of inertia or the angular momentum of the wheel? No matter the case both are factors in how much force (and thus torque) has to be applied to slow the wheel to a stop in a specified interval of time and in any description of the wheel’s behavior over time.

      Do you have physics that indicates otherwise? I’m interested in reading how you’ve proven Newton Mechanics false on the macro level.

      With that said, the one thing this sort of test doesn’t show is what happens if the body part experiences a big impulse when it strikes a disc. That’s a not a comment against discs. Hell, I think discs are great and won’t cause the horrifying calamity that so many seem to envision, but in the spirit of good testing and experimentation, we have to analyze the limits of any given test or experiment.

        • I could just be a person that understands physics and is wondering about this great revelation that inertia has nothing to do with what’s seen in the video.

      • I typed an elaborate comment, but it seems to have been withheld. Too bad. Anyway, the gist is this: We totally agree, but you didn’t read my comment correctly. I was specifically talking about comparing the controlled experiment in the video to an actual crash, not about the mechanics of the controlled experiment itself. Which is also what you did in your last paragraph, so we agree.

        • These day theres a lot of “Fact: XXXX” where the so called fact is just an opinion that may often be false/incorrect. This is exactly how your post read and why you were called out on it.

    • The same has already been tried by a lot of people using non-rounded rotors. Just Google and you’ll find several videos. The result is always basically the same. Click my name to see my – unsuccessful – attempt to cut myself with 2015 Ice Tech rotors (non-rounded). That being said: Rounded rotors are obviously big progress, without any down sides.

  2. Who cares! I still don’t want disc brakes on my road bike. I’d like to keep my large 700c rotors that have been built into wheels and skip the hydraulic mess and obnoxious disc brake rubbing, ticking, and honking issues.

      • Pretty much true, except a good percentage of riders don’t have climbs around that are more than a mile. Plus, I’ve never heard someone with years of racing skills say “yeah, I would’ve won, if only my brakes were better.” Good racers, whether alone or in a race, aren’t braking all that hard, all that often. Mountain biking and road biking do not have the same braking requirements, although they do benefit some riders greatly. Can’t it be possible that for some of us, the pros don’t outweigh the cons?

        • Sure they do, considering the bikes have a minimum weight limit of 6.5kg which brands are having such a hard time reaching at the moment… Disc brakes are WAY better than rim brakes and only conservative roadies who are afraid of change would be against them! Roadies today sound like mtbikers from the 90s who swore v-brakes were better and guess what? Today every bike has disc brakes!
          You know what adds 2.7mins up Alpe D’Huez? Not using EPO and being clean!

    • Have you complained to the phone company that you want your rotary dial telephone back as well? That may be your next step.
      The whole roadies hating disc brakes is hilarious to us MTB riders who have been running these since the 80’s.

      • While I agree with your statement, I am compelled to correct your “since the 80’s” statement. There were extremely few models available even in the late 80’s.

        In fact, most of the brakes on MTB back then were simple cantilever brakes since V-Brakes didn’t take hold until the early 90’s.

        Disc brakes on MTB’s didn’t see widespread use until the mid to late 90’s.

        • I was running them in the late 80’s. I custom made frame tabs and ordered Formulas direct from Italy. For my own use. Everyone caught up with me a few years later.

          • Formula did make a disc brake as early as 1987 (according to PinkBike), but it took more than a few years for everyone to catch up with you- it was fully another ten years before the first widespread mounting standard for frames came along, the Hayes 22mm mount, which in any case was later phased out. Into the early 2000s, rim brakes remained common on high-end race bikes. You definitely were way, way ahead of the times running discs in the late 80s.

        • Yeah, as I recall, a lot of XC racers were running v-brakes as recently as about 2000-2003 or so. I didn’t even have a bike with discs until about 2010 or so…. though admittedly way behind the curve on that.

    • @Jesse, don’t buy SRAM and you’ll have none of those issues. My Shimano discs are absolutely silent and do not rub if set up correctly. Most importantly, the have far better modulation than rim brakes and do not wear my rims.
      I’m not a racer but I do ride my bikes hard and ride through town to get to the wide open roads in my area.

  3. seems to me it will only be a problem when combined with mechanically doped bikes. can Mr Powers do the same test on a doped bike?

  4. Who cares! I still don’t want rim brakes on my road bike. I’d like to keep my small coaster brake that have been built into wheel and skip the cable mess and obnoxious rim brake rubbing, ticking, and honking issues.

    • Who cares! I still don’t want coaster brakes on my road bike. I’d like to keep my small spoon brake that have been built into the head tube and skip the hub mess and obnoxious coaster brake ticking rubbing, and pedaling issues.

      • Who cares! I still don’t want small spoon brakes on my road bike. I’d like to keep my track bike back pressure pedaling to slow or lock my leg to skid and skip the spoon brake ticking rubbing, and pedaling issues.

  5. We’ve had the new rounded rotors available the shop since January. Unscientific but pretty convincing tests abound, the most hilarious being the mechanics dropped a spinning rear wheel bike and all rotor first on to an exposed thigh. Had a red mark for a couple days, no broken skin. Don’t tell OSHA.

  6. nice video. next time instead of having the bike in the stand, have someone ride the bike at 40kph, brake hard for a couple of seconds, then grab the rotor. let me know how long it takes to get full use of your hand back. big difference between un-weighted bike, and a bike with a rider.

    • When in a road bike pile up crash does a bike stay upright with a rider while somebody is against their wheel? It doesn’t happen. I’d you’re touching a disc brake bikes are flying or on the ground already.

      Hell, I’d take the disc brake over my hand in the bladed spokes all day every day.

    • Usually there is no weight of the rider on the bike when the discs touch another person. Ergo, easy to stop the wheel.

  7. I give him 3000 euros if he does the same thing after a 10km downhill, when the rotors are over 100 degrees.

    After a descent, I though my rotor was loose, stupid of me, I touched it with my fingers to check it, burned both fingerprints. Fingerprints fully erased in 3 seconds.

    fake news, sram sponsored.

      • Pretty sure he’s talking celcius.
        That said, it’s not really much worse than rim brakes – rim brakes dissipate heat faster but its not instant either and both will burn you for sure – (still better than chopping a finger, though i’m more scared of pedals, spokes, chain rings and handle bars personally speaking…

  8. honestly though, a paid spokesperson telling you something is safe isn’t exactly objective, unbiased reporting. the test would be much more accurate if he heated the rotor up first, then slammed his shin or forearm into it at 40 mph. something tells me the result would be a little different.
    disc brakes? whatever, it’s a brake. if you’re really fighting to help out manufacturers, good for you, but my fat butt can lock up a rear wheel just as fast with a caliper brake. they are also lightweight, super easy to adjust while riding, and make wheel changes easy. i really can’t see what the fuss is about beyond just selling more stuff to roadies, which is already like shooting fish in a barrel.

    • A five year old can skid on a coaster brake. Locking the tire up means nothing when talking about braking performance. Disc brakes are about power and modulation not skidding.

    • So expect a 40mph speed differential between someone’s body part and that rapidly approaching disc, eh? Yeah, that doesn’t doesn’t sound realistic at all.

      That you can’t see the pros to disc brakes says more about your myopia than marketing.

  9. Quite interesting that the tester was not confident enough to stop the disc brake by putting his fingers or his nose or ear into the fingers of the rotor as would likely happen in the case of the crash in a peloton.

  10. What a silly test. There’s almost no weight behind his hand. He needs to put about 200lb or more of pressure behind his hand as he pushes onto the disc, because that’s what might happen in a real crash.

  11. I personally detest ‘Disc Brake Superiority Deniers’…we need to get rid of them to Make Cycling Great Again…

    …for all you ‘it will chop of my fingers and burn away all my flesh’…I present to you the Shimano Freeza disc rotor.

    Goodnight.

  12. Why does no one mention the fact that disc brakes add weight (indisputable fact) and more weight adds time up hills (indisputable fact)

    Who gets dropped on a downhill?
    Who get’s dropped on a climb?

    Disc brakes make you slower up hills! I don’t want to be slower up hills.

    • Cool story, but the discs actually make it possible to brake later. Not because of the stopping power, but because of the stopping feel. You will know exactly what you are doing, and therefore be more confident.

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