While at the TRP booth looking over the prototypes for Aaron Gwin, we heard an interesting discussion about Shimano and the UCI working on guidelines for round-edged rotors. Having just been at Hope Tech and seeing their rounded discs for their new road bike braking mod, ears perked up and we started checking in with all the big brands.

Word is Shimano has been finalizing a rounded profile radius spec for disc brake rotors on road bikes. Once approved by the UCI, they’ll release the specs as open source and all brands will be moving toward that shape on the outside edge of the rotors to get them back in the pro peloton. It’s not necessarily going to be a new “standard” with defined radii or shaping, but the UCI will definitely want all the brands to be doing it…

Hope Tech's rounded rotors may have been prescient.

Shown here and at top, Hope Tech’s rounded rotors may have been prescient.


Only two brands had something to see at Eurobike. Hope Tech’s were on display…


…and SRAM had a prototype behind the curtain. SRAM’s rotors are laser cut, which doesn’t put a lot of heat on it to distort the rotor, so to round it they’ll simply put it into a CNC machine to mill the the edge off the rotor.


SRAM’s rounding isn’t quite as dramatic as Hope’s, more of a de-sharpening.

SRAM’s plan is to have them shipping as early as October as a running change. They weren’t able to comment specifically about the actual rules or details they’re getting from the UCI.

According to Paul Lew, now with Edco and who sits on the UCI committee that looks at such things, here’s the status of discs getting back into the races:

“The disc brake test program will continue in 2017. This means we will see disc brakes again in the professional peloton for select races in 2017. Approximately one year from now the results of the test program will be evaluated. At that time next steps will be discussed. At this time there is no decision for a date when disc brakes will be approved as standard equipment for UCI competition.”

Is any of this actually necessary? We overheard several people in the know saying the actual event that led to the banning was not only of questionable accuracy, but that reactions were a bit too knee jerk quick. Besides, as the TRP guys said “have you ever felt a bladed spoke?” To which the SRAM guy added “yeah, they’re like small knives.”


Looks an awful lot like a Magura rotor, no?

As for the other two big brands, Campagnolo is not releasing technical information since their disc brakes are still under development.


Shimano’s tech rep said “We will of course follow the UCI’s recommendations and guidelines; we will have to. As you can tell, we are committed to disc brakes, I think it’s only a matter of time.”


  1. Birdman on

    Love it, the main benefit for me is the reduced possibility of frame paint damage from wheel installation. Least of the pro’s worries.

    • sad on

      Iwas thinking all like “so its going to just make them more expensive for the rest of us with no real benefit”.

      But you’re right. Every now and then i hit the frame and it damages the paint over time. This will def. help and that’s pretty cool

    • typevertigo on

      Have you had this sort of problem occur on your bike? Just curious.

      I have a TCX SLR 2 with TRP Spyre calipers and TRP’s rotors. I take off and reinstall the front wheel on the bike on a daily basis, and it’s got QRs all around. I haven’t really had frame paint scratches from rotor scrapes in the two years I’ve had the bike – although I do sometimes get the rotor’s edge hit the caliper instead of slotting in between the pads. No harm done on the Spyre in my experience.

    • DJ on

      All of this debate on discs in the peloton doesn’t mean a thing. On Friday, Sept.2, 2016, the UCI released a statement, ““We [UCI] decided to suspend the trial of disc brakes in road races following a request to do so made by the Association Internationale des Groupes Cyclistes Professionnels (AIGCP) – which represents all professional cycling teams. We are continuing to evaluate the situation and the test will not restart unless we and those representative groups believe it should.”

  2. Jon Jon on

    knock on wood, I’ve never gotten hurt from disc brake rotors, but chain rings? I’ve gotten cuts more frequently from chain-rings than i care to remember.

      • Jon Jon on

        none. I’ve never fallen on rotors spinning at speed. Though, with that being said, if someone falls on a spinning anything, injury(s) will occur. That kind of circumstances is not exclusive to disc rotor only.

      • i on

        I’m not going to straight call you a liar, but I’d like to see video of one of these crashes. It’s been a good 10 years since I’ve seen a MTB without discs, seen hundreds of crashes, burned myself on a hot rotor in a crash a couple times but never seen anyone get cut.

        maybe the guys you ride with have an uncanny ability to shove themselves between the fork leg and wheel when they crash; I’ve never seen such a thing and can’t picture how it would go down. Like mentioned above, how is it spokes are safe, but an equally sharp rotor a couple mm away is instant death?

    • JNH on

      I have seen a finger removed at the third knuckle by a brake disc. I have also seen many people get burns from landing on them in a big crash. Given the close proximity a pro peloton rides in I’m surprised teams aren’t experimenting with vented disc covers, to reduce the likelihood of burns more than anything.

      • Bobby Velo on

        Oh come on, this is the type of thinking that puts everyone on their heels in the first place. The only time rotors are hot enough to burn someone would be during a LONG descent, while on the brakes for long stretches of time. In those cases, the peloton are never riding 5 abreast for large pile-ups (they are strung out single file). The only time you see people on top of each other during a crash are on flat to rolling sections of courses when they are either going fast (and not on the brakes) or going slow when they are 10 abreast through a feed zone (also not on the brakes)… What about the sharp teeth on chainrings, and bladed spokes? The danger is being blown WAAAY out of proportion here!

  3. Ripnshread on

    I have scars from stitches I needed for a chainring to the lower calf. Disc rotors are most dangerous when hot. Iv’e accidentally leaned against one after a run, that left a scar too, looked like a disc rotor, but it went away the chainring cut to my ligaments.

  4. LowRider on

    I’m still not sold on disc brakes, it’s a wonderful solution in search for a problem. My ultegra and dura ace calipers work just fine with swissstop brake pads, on carbon rims, under rain, descending alpine passes. In the end, if you’re dragging your brakes you’re doing it wrong.

  5. dustytires on

    Don’t think pro roadies get chain ring gashes much as they ride the big ring more than the rest of us, a lot more. Recently switched to DA calipers after going fom months and miles on a disc equipped gravel bike then switched to a real road bike and a sudden reminder of the superiority of disc braking, not really in total power but the feel of action is way better. Dura Ace calipers are plenty strong but discs feel lovely.

  6. Graz on

    On one hand, why not make something safer if it can be? This is a pretty simple idea that ought not to add much to the manufacturing of rotors, and as others have mentioned has side benefits (smooth insertion mostly).
    On the other… how much safer this actually makes a rotor is pretty damn dubious in my opinion. Whatever your thoughts on that I would wager that NOT having disc brakes on a big wet descent is more dangerous. The UCI has a responsibility of safety, and that doesn’t always mean ultra-conservatism.

    Finally, there are loads of arguably more dangerous pointy things on bikes – chainrings and spokes as others have mentioned – that apparently no one is worried by because those dangers aren’t novel. What makes developing ‘safer’ rotors more important than ‘safer’ chainrings or spokes? More to the point, what other regulatory changes could the UCI be focusing on that would have real benefits? *Cough* barriers and motor bikes *cough*

  7. Jeff on

    I have always wondered how long it would take for them to do this. I know why they don’t want too but it makes the product so much safer.

  8. Ryan on

    “rounded” Let me get this straight, we have a HOT metal disk, that is only a few mm thick, and “rounding” it is going to make it less dangerous? Not a chance. Disk brakes have no place in the pro peloton, CX races, MTB races, TT’s? Sure. Not in the peloton. Rounded or not, they will still slice people open in a crash, I guarantee it. I feel like any “rounding” possible is only going to make the rotor more knife-like.

    Fact of the matter is, there have been a few situations when rim brakes couldn’t generate enough braking force in a road race, yes, but those are few and far between, and are often due to a very risky move on the riders part. Riders have had no problem locking the wheels up with a rim brake for years now, how much more braking force do they really need?

    • Bobby Velo on

      talk to any pro racing the Giro in in the snow, or COLD rain, while they descend for 30 minutes and can’t feel their fingers – if they want disc brakes or not.

    • Wuffles on

      Why do you think a “HOT” (FYI the temperature of a cutting edge has nothing to do with its ability to cut) disc a few mm thick will somehow turn in to a buzzsaw on a road bike? Mass start Mtb races like Megavalanche and Les Duex Alps have been having high speed pile-ups for over a decade. If it was an issue, it would have popped up before now.

      And as far as braking force goes, locking a wheel is not an indication of power or a safe way of stopping a bike. Disc brakes can be modulated better than rim brakes, especially in wet conditions. Modulation means better control over braking, which is why we put ABS on cars.

      But let me guess- we should be going back to penny farthings because all this new technology is clearly dangerous?

      • Ken on

        Actually I would venture to say hot objects cut through fat very. well once it makes it through the skin, which might be easier while the disc is spinning, it’ll slip right through the fat.

    • fishey72 on

      Ryan, it is not about braking power. I guess you have not ridden a disc braking road bike to feel the superior level of control you have. Control in all conditions, on any rim material.

    • Robin on

      It has little to do with braking force and “locking the wheels up.” Instead the benefit to disc brakes are better modulation, more consistent braking, less effort, and better all weather braking. Someone could use your logic to say, “Why do we need dual pivot brakes? I can lock up my wheels with a single pivot brake.” No matter. Disc brakes are coming and will be the most common brakes on road bikes in the near future.

  9. TheKaiser on

    Other than the minor increase in manufacturing cost, this seems like a no brainer. As others have said, the finger removing aspect of rotors generally comes from their spokes, not from the outer edge. I would imagine that rotors with aluminum carriers, like the shimanos, would be better in that regard, as the spokes would have a broader and blunter shape than your standard all steel design.

    And yes, if safety is a priority, it seems reckless not to add chainring guards to all DA and Record big rings. 😉

  10. andy schwartz on

    those campy rotors are nothing like maguras….. maguras have a “wave” pattern (patented and licensed by galfer) on both the top and bottom sections of the blade where as these rotors only have it on the top portion….this design will actually run hotter with uneven pad and rotor wear as opposed to the magura and galfer rotors

  11. Collin S on

    I wonder how many teams are going to put the money into disc brakes after this years snafu. There were a few smaller teams that said that they were only going to have disc brakes, then when the UCI put the kabosh (didn’t want to use a horrible pun) on them after Paris Roubaix, they had to get all new bikes and wheels essentially overnight. With limited budgets, how many teams are going to put that much resources into something that risks having another ban put on them after a highly publicized crash?

    • Kernel Flickitov on

      Every team is testing disc this off season. Ventoso and Movistar were caught lying about Roubaix when confronted by the press and the teams that were testing disc that day. The common theme being; how does one gets cut by a disc rotor when none are around Ventoso when he hit the deck? They also showed them the video to back it up. Their response, “no comment”.

      It’s going to be a few years while standards settle down and the logistics are sorted, but disc is coming like it or not.

  12. DRC on

    Called it. Rounded rotors will be the turning point in UCI legal discs. But seriously, the bladed carbon spokes on my Mavic SLR wheels would surely cut your finger/bird/squirrel right in half, so how have those never hurt anyone? Or the chainring? Are people going to fall straight into the wheel hubs more than they have the crank?

  13. Allan on

    Wow, I’ve never seen such a non-story have such legs before. How many stories can be written and commented on about disc rotors, LMAO!!!

  14. Jeff on

    I still can’t believe the chatter from some of how dangerous a disc rotor is..nonsense!
    Spokes and chainrings have and always will be much more dangerous than disc rotors, but it seems that no changes have been made to make them safer, if anything, they are now more dangerous( bladed spokes). Also, how hot is a rotor going to be in just about anywhere in any peloton, where riders are bunched together? The only sitution I see a hot rotor is with prolonged braking, and how many times is there prolonged braking in any peloton?
    This is a non issue brought on by the ” traditionalist’ in the sport that can’t forsee the future. I guarantee that within five years, we’ll all be laughing about how ridiculous an arguement this has become….while we all ride disc brake equipped road bikes.

  15. D P on

    The real issue is disc brakes are HEAVY! New 2017 Pinnarello, over 5 grand, over 20 lbs with disc! 11 thousand $ BMC with disc, 17lbs! A substantial weight penalty for a completely “unnecessary” piece of tech. Bike brands just need you to look at your rim brake bike and feel sad and open your wallet. Now we are seeing less and less true race bike choices from our favorite brands in 2017.

    • Kernel Flickitov on

      There are something like a half dozen disc road bikes that are coming in at the UCI weight limit for 2017, a couple below. Weight is almost a non issue, but thanks for letting everyone know your research is lacking.

  16. John P. on

    Nothing change with rounded rotors!
    The sides of the disk will still sharpened by the use of braking and the “rounded”
    section will have BETTER penetration than squared.

    Shimano continues to impose their will for profit on UCI.

    We have to save road cycling, shimano deserves a boycott from all of us.

    • ZeGerman on

      Why would they deserve a boycott, they launched something that makes my Riding safer with better control and modulation.
      The UCI´s reaction and all other cycling authorities was a complete joke.
      Ban all brakes because you could have your finger stuck between the tire and the pivot brake.

      • John P. on

        Please don’t insult our intelligence.
        There is NO NEED for more power until 32mm tires.
        disk brakes with 200mm? diameter will NEVER get the braking information of 622mm
        braking surface of rims.. elementary physics.
        Road bikes loose ~350gr and gain up to 1Kg while LOOSE their service autonomy
        that have among their status.

        Shimano knows and still use its’ power to impose this on UCI.

        We the people that find health, joy, autonomy etc in road bikes we must boycott
        the exertion of this colossal company to enslave road cycling.

        please don’t feel defensive, think physics, think logic

        • bergsteiger on

          If thinking physics, please do not leave out the convenient for your argument portions of the equations. Just using the brake track surface is leaving out tons. please use the logic you call out to involve all the variables, not just cherry pick the ones that support your argument.

          the points on service autonomy are valid, the weight I have not researched and do not care to. Unsure if Shimano is really pulling the strings, as it seems that every company supplying road drivetrains either have/announce/planned disc brakes.

          • John P. on

            I think that we talk about the same. The variables that our brakes called to manage
            doesn’t change calculably.
            Disk brakes will handle the same forces at same conditions with rim brakes.
            Same mass plus the weight of disks system, minor.
            Same speeds, same races etc. We charge the front system almost 6ton as hobbyists
            and something close to 4.5ton as pros….

            Don’t get me wrong about disk brakes. I like them, i can see the difference in their power and i prefer them for their stable performance, on my cyclocross, there where i
            take advantage of their performance in mad/tires combination. On my touring bike, there where i load a lot of extra weight and ride in every weather condition…

            Not in peloton as i already describe above, there is absolutely no need and we shouldn’t accept any reconciliation about safety, autonomy and performance.
            Why under UCIs’ approval? Why in road races? Why “officially”?
            For money for sure but money control us almost the same and there is no
            need or excuse to sacrifice the free spirit of road racing bikes.

  17. Marin on

    The only reason disc brakes will become norm has little to do with better braking.
    It’s all about profit:
    More often pad changes
    More expensive pads
    Harder to set up and service
    Need for expensive oil, rebuild kits etc
    New component: rotors

    Right now you’ve got rim brake that you need to change cable and pads maybe once in 2 years. Cost: 10$ or 20$ pair.

    Disc quipped bike: new rotor, 4x pads, at least one bleeding over 2 years. Cost: 100$ per brake or 200$ for a pair.

    Not to mention DB specific frames and wheels are going to go up in price and all the nice wheels for rim brakes are going to be cheap, so remaining at rim brake bikes is going to be better than ever.

    • uzurpator on

      I solely use discs on all my bikes. I have yet to replace pads on my road bike, after a year of use, and in 10 years of my riding, I have never needed to replace a disc. You are exageratting.

  18. Tony on

    I have a few road bikes. One is a year old and has hydraulic discs. You can guess which bike I prefer using! Sure, I’ve had to replace the pads, but none of the naysayers’ purported problems have eventuated and the sky hasn’t fallen down.

  19. john smith on

    This has got to be the funniest thread ever read… Disc are a sure thing. They are coming. I dont see teams switching all gear in them but they are coming. All my UCI racing athletes and I agree, it would be much better. Not tomorrow, but very soon. Giant is going all disc for example. Give it 3 years and its a done deal everywhere. The stuff you read about pill ups and fingers cut every week ina MTB race… my god what a load of bull. Have you people even serviced a pro team ? Come on man. Discs are better and safer, end of story. Their execution is just a bit untimely.

  20. John on

    I’ve believe I’ve seen rotors slice the limbs off of 25 innocent children. Don’t ask for proof, just believe me. I love new technology that improves the biking experience, except for those times when I don’t love it. Regardless, I’m an expert.

  21. satisFACTORYrider on

    i saw a guy get stabbed by his own top tube when his carbon bike exploded upon impact with a curb during a rain soaked twilight crit cuz zero brakes. this happens all the time according to statistics i’ve just made up.

  22. cracked frame on

    No one has asked the real question: Why does the UCI matter? Who cares what they think. Companies that bend to their knee-jerk reactions to make products fit their BS and out of date rules, should be boycotted by every cycling consumer/customer. They aren’t for innovation. I’d say they stifle innovation and the advancement of any new technologies.

  23. john smith on

    BTW if you are in the USA in non UCI race. You dont give a crap, you can run disc just like folks did last week at GMSR. Also, listen to pot and potter in their latest podcast @ 30 Minutes http://cyclingtips.com/2016/09/cyclingtips-podcast-episode-11-floyd-landis-interview-part-2-with-dave-zabriskie/ This is exactly what the peloton needs with the new worldtour calendar. The amount of risk will always be the same, there will still be tons of pill ups, people are still going to get hurt. The reality is that you are going down an Alp col in the rain with a peloton, its just generally better. ABS brakes do not save you from stupidity, they just help more in many cases.

  24. Bucky Barnes on

    I say…take back the discs, take back the index shifting, take back the clipless pedals, take back integrated brake/shift levers, take back the tri bars, take back the carbon…bring back the 70s!!!! Woohoo!

  25. MBR on

    Take back aluminum and the pneumatic tire too. Give us back solid rubber tires, wooden rims, steel frames. The good ol’ days… Oops… Almost forgot, while I melting away in the past… Take back the drivetrain and let’s just reset to the penny-farthing. Ha!

  26. Dave Mohr on

    I think most people are missing a very important point…its not all about the brakes. Frame manufacture, and subsequently frame design and ride quality/experience is improved. Instead of making 3 pieces ,each side, each rear end is a single part. Through axles dramatically stiffen the rear end so that seat stays only control the seat post, not as part of a system to control the rear wheel. This is why the stays can be lowered as they now primarily for the seat post.. bikes WILL improve from disc brakes, and so will braking!

    • Jimbo99 on

      The bike hasn’t evolved appreciably in my lifetime. My 2015 Bianchi Kuma has disc on it, it may stop better than my Fuji MX-200 with rim brakes in certain conditions, but the Fuji is actually the faster bike of the 2. The differences 26×2.10 vs 27.5×1.95, rigid fork vs shock fork. One is a 3/7 vs 3/8 drivetrain. End of the day, brakes mattered very little, it was the motorists poor driving habits coming out of the wooded driveway or right hooking me that I’ve ever had a collision with a car. Pedestrians get right of way, so never have hit another person. Better braking isn’t the solution, when another cyclist goes down in front of you it isn’t because their rim brake failed and there isn’t enough time and space to avoid running them over, iy’s more a matter of luck of missing a bouncing body and bike.

  27. MurseDubya on

    I guess you’ve all heard by now, the UCI banned spoked wheels and pointy chainrings for 2017! The teams are all on Striders or using belt drives and everybody has to switch to disk wheels! Also, the uniform is standardized to inflatable sumo outfits! Finally, we’ll all be safe!

  28. Idontcare on

    I don’t care if disc are the future or not, but will someone please decide soon. Surely the pro’s should decide if they should be used in pro racing. Think they are not dangerous, run your disc wheel up to 30mph then put you hand on the rotor. No more dangerous than chainrings or spokes, unless I am missing something they are not replacing either of those but adding more potential risk into the mix. Too heavy, doesn’t matter if all the teams are using them. Are discs better ? for ‘s and against ‘s, uphill in the dry no, downhill in the wet yes. People should buy for their own circumstances, but will probable go for the same as the pro’s


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