Another pro disc brake crash

[Elefantino]

This from Welsh rider Owain Doull of Sky today. Was involved in a crash with Marcel Kittel's disc brake.

The can of worms has officially reopened.

[ceolwulf]

Thought they were using rounded edge discs already?

[FlashUNC]

Those poor Fiziks.

[MattTuck]

should not have happened, I thought they mandated all discs had to have rounded smooth edges. the plot thickens.

[tuscanyswe]

They are still only a couple of millimeters thick and spin pretty fast regardless of rounded edge.

[ColonelJLloyd]

Originally Posted by tuscanyswe

They are still only a couple of millimeters thick and spin pretty fast regardless of rounded edge.

Just how would a disc rotor have an opportunity to spin more than say half a rotation in contact with anything else during a crash? Think about it.

[tuscanyswe]

Originally Posted by ColonelJLloyd

Just how would a disc rotor have an opportunity to spin more than say half a rotation in contact with anything else during a crash? Think about it.

Are you saying you think the disc would make the same damage if it dident rotate upon impact? That the fact that it rotate has nothing to do with the damage?

Also, not every accident is a crash from the get go. You can easily plant a front disc into someones leg whilst still riding until there is a resulting crash.

[Mark McM]

Originally Posted by ColonelJLloyd

Just how would a disc rotor have an opportunity to spin more than say half a rotation in contact with anything else during a crash? Think about it.

Crashes often occur when cyclists get squeezed together. If two cyclists got squeezed together while riding slightly staggered from each other, the foot of cyclist in the left rear could go into the back of the rear rotor of the rider to the right front. Since the rear wheel is still on the road and spinning, the rotor would be turning quickly and with a lot of torque. If the two cyclists were in this position for 7 ft. of forward motion, the wheel would turn a complete revolution.

While not the same thing, I once had a cyclist put his front skewer into my rear spokes. Out of the 20 spokes of the rear wheel, 7 were broken, and an additional 6 were damaged. So, the skewer was into my wheel for most of a revolution (fortunately, I didn't go down, and rolled to a stop).

However, as it was the cyclist's left shoe that got cut (the right shoe would be closest to another rider's disc rotors), I can't think of an easy way for this to happen.

[ColonelJLloyd]

Originally Posted by tuscanyswe

Are you saying you think the disc would make the same damage if it dident rotate upon impact? That the fact that it rotate has nothing to do with the damage?

Maybe. If the damage on the shoe was caused from a rotor it could have been done without the rotor turning more than a half a revolution or so. The cut in the shoe looks to me like it could be a tear from the rotor hitting the shoe with force just as likely as a "slice".

This is all conjecture from any of us who post, right? Is there video of the crash?

[tuscanyswe]

Originally Posted by ColonelJLloyd

Maybe. If the damage on the shoe was caused from a rotor it could have been done without the rotor turning more than a half a revolution or so. The cut in the shoe looks to me like it could be a tear just as likely as a "slice".

This is all conjecture from any of us who post, right? Is there video of the crash?

I think theres a ton of difference. Yes much speculating. I do know tho, that if I'm about to get a weighted disc into my body i would prefer it to not rotate upon impact if everything else was the same .) Dunno if theres a vid, i guess we will have to take the riders word for it.

[KJMUNC]

There are a lot of pointy things on a bike that could cut you during a crash. This looks like something a disc could do, but so could a chainring.

[stien]

Sounds like a new product to me: disc rotors on freewheels that only lock when brake lever is pulled so if anything but the brake pad is rubbing, it just spins free!

[tuscanyswe]

Originally Posted by stien

Sounds like a new product to me: disc rotors on freewheels that only lock when brake lever is pulled so if anything but the brake pad is rubbing, it just spins free!

Not a bad idea if it could be put into practice.

[seanile]

Originally Posted by Mark McM

However, as it was the cyclist's left shoe that got cut (the right shoe would be closest to another rider's disc rotors), I can't think of an easy way for this to happen.

could be a mirror'ed phone picture...so whether it's the left or right shoe is an unknown

Originally Posted by KJMUNC

There are a lot of pointy things on a bike that could cut you during a crash. This looks like something a disc could do, but so could a chainring.

not really. chainring stops spinning when you stop pedaling. rotor keeps moving until the wheel stops. further, most crashes of consequence happen at high speeds, when the chain is in the big ring filling in the chainring's spikey death teeth. so you'd just hit the broad lumpy surface of a non-moving chain if you came in contact with that.

[pinoymamba]

https://www.youtube.com/watch?v=TPwDtl3ircY

fake news!