Joearch

I must say that while pedaling along I have looked down at the front wheel, thinking to myself that the brake rotor does remind me of a dremmel cutting tool. Thought a number of times if I were to come in contact with someone with my rotor tne results would not be good. True there are a number of dangerous parts on the bike, the rotor is extra scary.

Seattle Forrest

I didn't realize how dangerous wheels with spokes are, I'm going full disc to play it safe. Having trouble finding a front one, might have to go with a faring.

eduskator

''Questions safety of disc brakes''
I think there are a lot more people crashing because they lost their braking power due rim brake failures or inefficiency than people getting their ears cut by discs during a crash.

qwaalodge

True, the injury potential for losing brakes is far higher than getting into contact with hot, spinning disc rotors.

The biggest hazard of rim brakes is the tire or rim or both exploding during long descents in the warmer seasons. Apparently, the current solution to that problem (other than upgrading to disc brake) is minimize braking during long descents. A practice that can be quite problematic for many reasons especially when riding public roads

MoAlpha

One of the more memorable cycling injuries I've seen was what a chainring did to someone's calf in a Wednesday night crit crash.

big john

Mine isn't too bad. I can hardly see it anymore since I now have that old man skin. I have a worse one on my right leg from slipping off the kickstarter on my motorcycle when I tried to start it in work shoes.

popeye

Says Gavin Mannion who was also injured this week:

“Both crashes were pretty minor except the fact that I landed on a hot rotor,” Mannion told CyclingTips. “For one, I needed eight stitches in the front of my knee, and for the other, I needed 12 staples in my hip. The cuts were so clean it was almost like the rotor burned through it.”

bampilot06

Bikes should have both rim and disc brakes at the same time. Ultimate stopping power plus redundancy. What could go wrong.

himespau 

Outlaw platform pedals with pins or rat trap pedals. No way to know how many shins and calves have been carved up by those suckers over the years.

eduskator

It does make sense! Never thought of that to be honest, but rubbing brake pads on a wheel for an extended period of time must heat the whole thing pretty seriously.
Hot air = increase in pressure = assploding tires!

tomato coupe

!!!WARNING!!!! Not for the squeamish, but a chain ring incident suffered by someone I used to ride with:

======> DO NOT CLICK ON THIS LINK IF SERIOUS WOUNDS UPSET YOU <=======


Did you read the above warning??

https://4.bp.blogspot.com/-H45qNo6GC...0/IMG_2742.JPG

Mojo31

This sport is dangerous! Lot's of equipment designed to maim and injure people. I think I'll go back to couch surfing.

big john

I tried those peel and stick patches at one time and had one blow off on a steep descent when it got too hot.

Kapusta

By the time you end up in a pileup and coming into contact with a disc, it is not going to be turning very fast. The edge of the rotor is only moving a fraction of the speed of the tires.

Darth Lefty 

The EWS lately did a study about what kind of injuries riders were getting and how severe (in terms of days to recovery). Does road cycling have any similar stats?

qwaalodge

The rim braking heat weakens the rim material (aluminum or CF and keeping in mind, the tire pressure, is pushing hard against the rim edge). A lot worse if the owner did not bothered to replace the rim after the wear indicators have worn out.

And then, the heavier the rider, the higher the tire pressure, the higher chance of blowing out the rim when dragging the brakes in long, hot weather descents. Fortunately, many blowouts seem to happen at the rear wheel which is less dangerous than the front but still very dangerous especially if it happened 40mph downhill.

This is why you hear the advice very often, "do not drag your brakes in long descents". But it doesn't always work for everyone for many reasons and the disc brake is a most welcome tech for that.

Racing Dan

A lot less fast than you think. Assuming you go down at 30 mph, the edge of the disc, assuming a 160mm disc, is only moving at ((pi*0.16m)/2.15m) * 30 mph = ~7 mph, and that is at about 375 rpm.

seypat

This thing only weighs 12lbs. Plenty heavy enough to inflict major damage if swung as a weapon. Especially if you're a biscuits and mustard type of person. (that wasn't a rotor, though) Imagine how much damage it or something similar with a thinner blade profile could do attached to a 150lb projectile traveling 20+ mph. That's a lot of ballast with lots of force behind it. It's entirely possible. Not likely, but possible. I still think the chainrings would do more slicing damage. Blunt force, most anything attached to the bike will pack a punch.

Reflector Guy

LOL Reminds me of a "meme" we use on another forum..... Brake rotor threads are always a lively subject!

Kapusta

Chainrings are FAR more dangerous than discs. The danger could easily be mitigated to near zero with a dead simple and extremely light ring guard (like a bash ring).

I find it amusing that anyone frets over discs while they don’t think twice about the easily solvable issue with chainrings.

To be real, I don’t think either is worth losing sleep over, but to worry about discs before rings is just asinine.

bikecrate

Why can't this be tested and put to rest? You could take a dead pig's limb, spin a bike wheel on a stand up to speed, stick limb up to disk and see what happens. Then have barbecue pig limb later. Where's Mythbusters when you need them?

WhyFi

Yeah, it's all about the impact force, and that rotational speed is a bit of a red herring, but I think that this overstates it. The force behind it isn't going to be the full weight of the bike and rider - we're meat sacks loosely attached to the bike at best. Yeah, discs can cause damage in pileup but, as you say, that's the nature of high-speed collisions and I think it's silly how much they're demonized (by some), relatively speaking.

seypat

Also, unless the target is up against something solid like the ground or a wall to produce an anvil effect, you're going to have a lot of bounce and recoil reducing the blow. Like I said before, it's certainly possible. I'm just not seeing it. More likely the gouge came from something like a protruding axle, a shoe cleat or a pedal. Maybe even the edge of a brake caliper.

You also have a wheel there that will probably hit whatever first. I don't see a direct hit head on from the rotor happening.

Darth Lefty 

Rotational speed and how fast it's spinning is absolutely a red herring. When I put my finger on the disk above I was in no danger because it's not really very sharp but if I fell on it, it could cut something. The cheap Tektro rotor isn't that impressively finished, the edges are not rounded at all. The situation is more akin to a hatchet. That's a lot scarier, they should go with that. But in cycling, calling something a hatchet is reserved for saddles, for some reason.

Somehow no one in motorcycle racing or mountain biking ever has this problem.

Bearhawker

Airbags are obviously required. And seat belts to make sure you're positioned properly for the airbags to have maximum safety effect.