popeye

Hugo Hofstetter left with huge cut in ear after dramatic crash at Circuit de la Sarthe, questions safety of disc brakes.

https://www.velonews.com/news/road/f...th-disc-brake/

Seattle Forrest

Brakes at all are dangerous, what we need are rocket boosters, fixies, and some PBR!

Troul 

keep a safe personal space distance from all crashes.

WhyFi

How does a rotor cause a small puncture like the one that's in line with the gash? I guess I can't tell if that's a ridge or a valley between the two.

phrantic09

It doesn’t

ThermionicScott 

Dumb question... I don't have a lot of experience with discs, but how does a 2mm thick rotor become "razor-sharp"? I do have some experience with razors, and they are quite thin.

Wouldn't rounding the outer edge a bit keep it from getting sharp during a reasonable service life?

Troul 

not sure, but I'd be concerned of the barbed wire that the cables could transform into during a race.

WhyFi

Yeah, they're not razor sharp unless describing then as such is useful for a narrative. Shimano are certainly blunted, as are SRAM. I don't know about Campagnolo, but I would assume that they are, too. Of course, detractors will say that rotors cut better than you'd think because they're super-heated. Yeah, that one doesn't make a lot of sense to me, either.

FWIW you *can* get an extremely sharp edge out a nominal 90° angle, but it takes some work teasing out and burnishing that edge (which is how woodworking cabinet/card scrapers work). The rounding off that the manufacturers do should prevent anything near that level of sharpness for the lifespan of the rotor.

Darth Lefty 

It's about as sharp as a razor scooter

Mojo31

It doesn't, but if you spin it fast enough it will cut or tear through soft tissue.

Darth Lefty 

hahaha emphasis mine

Darth Lefty 

How fast do you imagine it's spinning?

Mojo31

Don't know. Put your bike on a stand and start spinning the rear wheel. Put your finger on the edge and see what happens. If no cut, increase the speed of the wheel and try again. Eventually, you'll find out what it takes.

Or, maybe he didn't get "cut." Maybe his ear got caught in something around the area of the disc and was torn in the melee. The article did not really say what specific injury he had. In lay usage, the word "cut" can mean a lot of different things.

Darth Lefty 

Perhaps we need safety razor discs with 5 blades

Seattle Forrest

I think the OP's point is that racing is dangerous and Big Bike should stop forcing it on us.

tomato coupe

I don't think there's any way that a disc brake rotor could damage a helmet like that unless it was removed from the hub and thrown by a ninja.

WhyFi

The new Shimano Shuriken™ rotors have awesome stopping power.

Darth Lefty 

Mojo31

Damn, bruv, brave move!

MoAlpha

If the discs are good and hot, they’ll self-cauterize the wound, making extensive debridement necessary, but preventing potential exsanguination.

big john

I have a chainring scar on my left leg from falling off of my mtb. Let's get rid of those dangerous chainrings.

Mojo31

They are like buzz saws!

Seattle Forrest

You guys should see my legs after an hour with kittens!

qwaalodge

I concur that chainrings, especially the biggest chainring on 2 or 3x is far more dangerous than disc brakes.

It's one reason I went 1x. No more exposed teeth from the chainring because the chain shrouds them at all times and 1x chainring tend to have more dull/wider teeth, less likely to cut even if exposed.

Racing Dan

The real danger is hitting the tarmac at 30 mph in a virtual bathing suit and an eggshell. - Happens in almost every pro road race. Blaming the brake discs is a red herring.