No thanks. I have already come to fear his botany powers.

This incident seems to be getting a little silly with Doull using the word lethal and focusing on the little cut on his foot. His disc brakes didn't cause the crash so if there was no crash it would be a non issue. Why aren't people concerned with the reasons for the crash?
Also, a little wound on his foot and he's dramatizing the cut to his shoe. Again no mention of the road rash all over his body and all his shredded clothing.
Even if the rotor cut his shoe, so what? It's nothing compared to the crash itself and the related injuries and damage.

I saw that - why not test the rounded edge disc, and compare the Hope true-rounded edge to Shimano's half ass effort of rounding? And why not just create a caliper mounted guard for the rotor and call it good and put the safety debate to bed?

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wovebike.com | Wove on instagram

Because disc brake aero would go from too bad to way too bad.

Nope. Guarantee they can make a disc fairing more aero than no-fairing. And it will happen - they just need to hurry up and get it over with.

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wovebike.com | Wove on instagram

And keep adequate cooling?

Heck, Shimano is already adding small fan blades to their disc mounts to get better cooling...I wonder how much "power to rotate" that adds? You're not moving air at 90deg to the direction of travel without a penalty :-/

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http://bikeblather.blogspot.com/

It would need extensive testing, which I'm sure they're doing. But, one option is a cover that mimics the coverage area of the caliper, leaving the middle fanned section open. Or just shield 6mm around the edge. And/or leave the section of the rotor inside the rear triangle exposed.

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wovebike.com | Wove on instagram

It still sounds to me like the most elegant solution is an inflatable rubber guard on the edge of the disc ;-)

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http://bikeblather.blogspot.com/

I'm holding off on disc brakes until we move to carbon fiber rotors

Dan, you really do need to get a "Like" button sorted

My monitor is currently wearing a mouthful of morning cappuccino!

"LIKE!"

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

Bladed spokes are far worse. Handlebars without plugs, shift levers, aero bars with bar end shifters, chainrings!

I rode an event a number of years ago. A rider fell and a following rider rode over him. The following riders big ring went across the back of the fallen riders neck. 8 days later the fallen rider died.

After watching the video of the bike shoe against a really fast spinning brake rotor, I don't believe Doulls show was damaged by a brake rotor. And I don't believe they pose any significant risk to cyclists. I'll be using them as soon as my savings account allows the purchase of bike #13.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

Your assumption is correct... no discs on road bikes then. Just the leader of a half fiddling with his front brake that was rubbing... I bet your wheels will smell awesome in a week or so.

Your burden of proof is pretty low huh?...and do you understand how that joke video "test" doesn't quite match the physics of what may have happened (i.e. Doull's shoe going into the front fork/disc of Kittel at speed)? Here's a clue...according to Alex Simmons, the kinetic energy of a spinning wheel is ~0.5% of the kinetic energy of Kittel traveling at the same speed. That's not simulated in those "tests".

Not to mention, for some reason Mr. Fretz only exposed the hard plastic toe box of that shoe to the disc :-/

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So I have seen plenty of videos of people trying to cut things on disc brakes and failing. Fair enough to say they aren't real world applications. But I can't find a video of one cutting something. Is there one? And I am being serious here, I just want to see one.

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Ian

I also want to see the test of the shoe pushed against the barriers with same force as the VN test. my guess is shoe still looks brand new after that one. it must have been aliens.

tkos wrote:

So I have seen plenty of videos of people trying to cut things on disc brakes and failing. Fair enough to say they aren't real world applications. But I can't find a video of one cutting something. Is there one? And I am being serious here, I just want to see one.

This should work for you (thanks to AlexS):
http://www.sbs.com.au/ondemand/video/668083779880/the-pioneer-mtb-race
FFWD to ~22 minutes


Looks to be a pretty nasty cut from falling on his OWN disc.

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Oh no, that wouldn't be fair...you'd need to hit the foot of the barriers with the same kinetic energy as real life in the test...oh, wait...

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That really isn't much of a video though. Dude fell on his bike that wasn't moving and cut himself. I've done that too on my chain ring while getting a stuck pedal off. Also the "I caught a glimpse and that was what happened" seems a little unscientific.

I have no doubt a rotor "can" hurt you, but is the risk that much increased over any other part of the bike?

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Ian

Again, that's not the point...the question is does it increase the risk as compared to other braking technologies. To compare the risk to other parts of the bike is the literal definition of a "red herring".

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There is a reason pro riders don't bitch about road rash: it's part of the inherent risk involved in their beloved sport. You can deduce from their comments that getting their appendages sliced off by a totally unnecessary piece of equipment is not what they signed up for. They would like to keep human tartar off of the menu.

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Oui, mais pas de femme toute de suite (yes, but I am not ready for a woman straight away) -Stephen Roche's reply when asked whether he was okay after collapsing at the finish in the La Plagne stage of the 1987 Tour

In the video you could see he was applying a considerable amount of pressure to the shoe, for quite a while. Plus the rotor was not circular, rather the type with dull teeth, more like a bread knife. Road discs are normally round from what I've seen. Also. Doulls alleged hitting of the shoe against the rotor would have been a split second at best.

While there are clearly are differences between the shoe test in the video and the alleged incident with Doull, I think the information gleaned from the video, is a pretty fair and reasonable representation of what happens when a shoe comes in contact with a disc rotor. With all the other bits of a bike that can cause damage to a rider during a crash, in my less than humble opinion, the risk posed by disc rotors is a non-issue.

Your mileage may vary,

I'm just glad that no cyclists have ever been hurt by rubber/rim brake equipped bikes.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

A split second, yes...but in the most likely scenario of how the slice got onto his shoe and how Kittel's bike instantly stopped, that would mean that a large amount of the kinetic energy of Kittel would have been imparted into the shoe in that extremely short time. According to some calcs by AlexS, the kinetic energy of the wheel shown in that video is only ~0.5% of the total KE of a rider traveling at 55kph. Not understanding that important difference is a failure of understanding the physics at play.

RChung mentioned that most people have stopped a rear wheel from spinning in a stand just by gently touching their palm against the tire. No big deal, right? Now, think about what you would expect if you got up to 55 kph on a bike and then tried to stop yourself by pressing your palm against one of the tires. There would probably be some injury, no? Well...that's the difference in physics we're talking about.

Lastly, do you notice he's only exposing the hard plastic toe box of the PI shoe to the rotor...the slices in the Giro Empire shoe of Doull were in much "softer" locations...

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Tom, I like you. You're about as pig headed and stubborn as I am. That's not easily achieved and is an accomplishment you can be justly proud of. Welcome to the club.

As a mechanical engineer and long time cyclist, I'm reasonably aware of the forces involved and the consequences.

and just to keep the discussion going, would a softer shoe on Doulls foot not have given way more easily than the hard shoe in the video? Have you ever tried to slice a pillow with a knife? It's a pain in the butt, because the softness of it keeps it deflecting away from the knife. It's only when you push down with the knife to the point of refusal, that the pillow starts to be cut.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

If you think that him holding a shoe on the rotor is even remotely applicable to the 190lb Kittel traveling 28 mph, you really need to brush up on your physics.

Did Doulls allegedly disc sliced shoe and boo boo on his foot require an ER visit? His road rash butt may have needed a nurse to wipe it clean but he foot was fine. Probably didn't even sting in the shower.

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"