UCI approve disc & looking at weight limit

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MoPho
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by MoPho

Calnago wrote:Uh... Here in the U.S. I think that is exactly how the law works. Products really do need to be idiot proof here, probably more so than any other country in the world. Car brakes are a good example.



Actually, the average car brakes can fail just the same as the bike brakes if you ride them all the way down a mountain pass as per the above tests
Brake Fade: http://en.wikipedia.org/wiki/Brake_fade
There is a reason we are taught to let the brakes cool and use low gears to compression brake down hills

Sure car (bike) companies have to make things idiot proof to a point, but they are still trying to meet cost targets that alters where that point is. You can't really buy an inexpensive car with fade resistant brakes, such items are reserved for higher end performance cars, and even many of those you can get the brakes to fade if you push them really hard

By your " completely idiot proof" argument, inexpensive bikes (or cars) could not exist. What's to stop someone from getting on a $500 hybrid bike with low end disc brakes (these have been out for years) and go careening down a 4000ft mountain pass riding the brakes until they fail?


.

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mattr
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by mattr

LeDuke wrote:At what point is the individual actually responsible for his or her own actions?
When they run out of money to pay their lawyer
LeDuke wrote:I can find dozens of examples of accidents where police cited operator error, which resulted in the overheating of brakes, when thousands of other people, operating vehicles in similar conditions, had no such problems.
And speaking from experience, that's no blocker to the operator, or their insurance company suing.

They failed to use them properly as the instructions weren't clear enough, safety margins weren't big enough, there were no warnings, you built it wrong. And so on.

mattr
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by mattr

MoPho wrote:stuff
Except cheap cars are tested in exactly the same way as expensive cars, and they (usually) pass the same tests. e.g. braking from 80% of Vmax to stationary 30 times with no fade or failure in a 1 hour period. Only difference is the expensive car gets to Vmax quicker, and it's a higher speed. The "extras" that go in at the design phase, over and above these minimum legislative/common sense ones aren't actually required.

If you go to one of the testers favourite locations (Gros Glockner for instance) it's not unusual to see lines of cars in all shapes and sizes dragging brakes down the pass with a 1000+ kilo trailer on the back and 5 up. All the way from €10000 skoda hatch backs to €200000 Audi super saloons.

And FWIW I've seen how mtb brakes are functionally tested, and there's essentially no difference between xtr and non-series.

MoPho
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by MoPho

mattr wrote:other stuff



I do work for car magazines and a number of years ago we did a measured brake fade test, from entry level up to SUV and performance. The difference in fade, pedal pressure and pedal distance required can be dramatic and some even resulted in scorching of the rotors just like the picture posted earlier.
We had done multiple stops from 100mph with variations on time to cool down between runs. For example by the 9th stop, the Honda Accord stopping distance increased by over 100ft and the brake pedal went to the floor on the 12th run, this was with 90s of cool down between.
The high end sports cars were so unaffected that we had to reduce the cool down to 20s and they still did 35 runs unfazed

Now of course cars are designed to meet a higher standard of "idiot", but fact is you CAN overheat the brakes on your car if you are hard on them. Heck, I've experienced brake fade when I had my Subaru WRX on a rather feisty twisty mountain rd drive and I wasn't even riding the brakes.

Harmitc
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by Harmitc

Thanks to the US one of the first things you buy as a keen cyclist is a very fine flat file.

eric
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by eric

There was a disc brake bike in my road race Sunday. There were no crashes due to the rider with discs slowing more abruptly than everyone else on the descents, and I did not see any body parts cut off by the discs.

superdx
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by superdx

It's kind of amusing that people keep trying to use the amputation/cut thing as an argument. There are at least 10 discs already spinning on a normal road bike already and people don't seem to be getting sliced up on those, even there's 1 particularly large spinning disc already, and yeah they're called cranks and cogs.

Cheetahmk7
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by Cheetahmk7

superdx wrote:It's kind of amusing that people keep trying to use the amputation/cut thing as an argument. There are at least 10 discs already spinning on a normal road bike already and people don't seem to be getting sliced up on those, even there's 1 particularly large spinning disc already, and yeah they're called cranks and cogs.


Perhaps, but until discs are used in races for quite some time we won't know the additional cutting/amputation risk. Missing end caps in handlebars can seem pretty innocuous too and yet they have killed people.

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Benno
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by Benno

Discs have been used in mountain bike racing for like 12 years. Those starts can get pretty congested. An elite race can have 100+ riders sprinting for the first section of trail at 50kph. At the 24hours of Summer Solstice there must be 600 riders off the start all packed just as tight as any road race. I can't recall any disc related injuries, I'm sure there are a few but they seem to be as rare as any other unlikely hazard.
As for the pics of melted and scorched discs, that's an easy target that I don't feel proves much at all except user error. For every melted disc picture I'm sure there are a lot more rim brake failure pictures.

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maddog 2
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by maddog 2

Cheetahmk7 wrote: Missing end caps in handlebars can seem pretty innocuous too and yet they have killed people.


the end caps killed someone?

LionelB
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by LionelB

pushstart wrote:
I would love to hear more from the folks that have been using discs on the road and would rather switch back to rim brakes. I am not being facetious, as I believe such testimonials do exist, I just haven't heard anyone voice that opinion yet. It would be more interesting than people rejecting technology with which they have little to no experience.


I have a bike with shimano hydro road discs (I use this bike mostly on mixed road/dirt rides). I would not switch my main road bikes to discs. Overall they work OK. They are no game changer though.

In dry weather I would take my campy brakes on carbon rims any day. I find that modulation is better, they are lighter, they look much better, etc.....

The only situation where discs are clearly better is pouring rain, not just a wet ride or showers but pouring rain. I had a couple of road rides with this Crux in heavy rain for hours, in this scenario it is much better than rim brakes. But this is it.

Image

pushstart
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by pushstart

LionelB wrote:I have a bike with shimano hydro road discs (I use this bike mostly on mixed road/dirt rides). I would not switch my main road bikes to discs. Overall they work OK. They are no game changer though.


(Beautiful bike. I love that new orange/red color scheme!)

This is great commentary. Obviously not all rim brakes and rims are created equal. The modulation (and overall stopping power to be sure) is much, much better now with Spyres + HSX rotors than on my previous carbon-rim + Sram Rival setup. But I know that there is a big world of rim brakes out there and appreciate the alternative perspective.

Hopefully (and surely) the tech for the road will continue to see significant refinement. I am interested to see what becomes available and affordable over the next couple years. (Wondering what Campy's offering will look like too.)

LionelB
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by LionelB

Once it becomes UCI approved I certainly expect to see significant progress. Right now I think my Shimano hydro are "state of the art". This should change fairly fast.

centhar
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by centhar

These "road" disc brake designs that will be used in a racing application are just more robust MTB parts. Why no ground up design for road racing? :noidea: The front rotor will need to be bigger (200mm?) along with the caliper pots to shed more heat at high speeds and on descents. These parts will need to be heavier and that will be quite a tradeoff.

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eric
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by eric

superdx wrote:It's kind of amusing that people keep trying to use the amputation/cut thing as an argument.


Yea, my body parts comment was ironic. Discs aren't sharp, won't cut anyone and they hide next to the much larger wheels.

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