Tour Magazine Video on road discs

[oldpotatoe]

Anybody speak German?

http://www.tour-magazin.de/technik/so_testet_tour/video-praxistest-scheibenbremsen/a30097.html

[ergott]

I'd like to know more too.

[HillDancer]

Two things are obvious without words, carbon fork flex, and Ice Tech rotor failure.

[oldpotatoe]

Two things are obvious without words, carbon fork flex, and Ice Tech rotor failure.

Lots of squealing too..

[gavingould]

properly bedded pads/rotors before this test? did i catch something about that clamped on weight being +100kg or putting total at 100kg?

[ergott]

I have the 140mm rotors and my brakes are silent. That's why I'd like to know more. Maybe the pads were contaminated?

At worst, if this is a legitimate issue I think it can be resolved with a brake pad designed for more extreme use. That was a lot of weight and some hard braking. I was expecting to see glowing rotors before pad failure.

[gavingould]

i've got 160mm on mine. whatever pads come with the r785 setup have been quiet so far.
i'm 100kg but there is no descending around here.

[xeladragon]

Slight thread drift but...

I just ordered some Ice Tech rotors but I'll be using them with TRP Spyre calipers. I hear the stock Spyre pads aren't great, so looking to pick up some Shimano Ice Tech-specific ones that are good in dry and wet conditions. Which pads should I be looking at?

[saab2000]

They admit it is an extreme case and added mass to the rider and bike to get it to about 100kg of weight for the rider and bike. They picked a challenging, steep road for the descent.

Hard to say what caused it to fail. Obviously this type of braking takes place on mountain bikes all the time, so it's not like this is unprecedented.

[oldpotatoe]

They admit it is an extreme case and added mass to the rider and bike to get it to about 100kg of weight for the rider and bike. They picked a challenging, steep road for the descent.

Hard to say what caused it to fail. Obviously this type of braking takes place on mountain bikes all the time, so it's not like this is unprecedented.

What failed? Pads? Rotor?

[ergott]

Someone said the video explained that the rotors are made by sandwiching aluminium with steel. The aluminium core of the rotor melted.

Still puzzled.

[tuscanyswe]

I have the 140mm rotors and my brakes are silent. That's why I'd like to know more. Maybe the pads were contaminated?

At worst, if this is a legitimate issue I think it can be resolved with a brake pad designed for more extreme use. That was a lot of weight and some hard braking. I was expecting to see glowing rotors before pad failure.

more extreme use? Its mostly scrubbing speed in this video is it not? Sure its downhill with a heavy rider but far from extreme or at least the way i c it.

And that sound, reminds me why discbrakes are not an option for me. Completely ruined what could have been a great run.

[ergott]

Look at the %grade he's going down that's displayed.

I think more needs to be known/understood about this. Shimano has been making disc brakes for years now. Ice Tech isn't new either.

This video is from another company (TRP), but demonstrates a far more extreme case and the brakes work just fine.

https://www.youtube.com/watch?v=5_YREtBNCkI

[MattTuck]

They admit it is an extreme case and added mass to the rider and bike to get it to about 100kg of weight for the rider and bike. They picked a challenging, steep road for the descent.

Hard to say what caused it to fail. Obviously this type of braking takes place on mountain bikes all the time, so it's not like this is unprecedented.


A road bike is by its nature very fast going down hill, low rolling resistance and the roads tend to be long grades of incline/decline which mean you have to stay on top of the brakes to keep the speed safe. Mountain bikes have a lot more rolling resistance, and trails generally require you to scrub speed less frequently, and you're not going as fast, so you have to dissipate less kinetic energy.

[tuscanyswe]

Look at the %grade he's going down that's displayed.

I think more needs to be known/understood about this. Shimano has been making disc brakes for years now. Ice Tech isn't new either.

This video is from another company (TRP), but demonstrates a far more extreme case and the brakes work just fine.

https://www.youtube.com/watch?v=5_YREtBNCkI


Yet one is just a google away from reading about disappointed users for the trp brakes.

Im sure discs on road bikes will be great eventually tho. Just dont think we are nearly there yet.

[ergott]

Cross post, but relevant. I'm not sure what happened in that video.

That was the aluminium core that melted? I thought the pads disintegrated. Aluminium melts at 660C. Wouldn't the rotors gotten red?

"Doesn’t really matter what the emitter is…stainless steel, cast iron, tungsten in your light bulb, the temps are about the same for a given color. Generally accepted colors/temps are:

C F Color

400 752 Red heat, visible in the dark
474 885 Red heat, visible in the twilight
525 975 Red heat, visible in the daylight
581 1077 Red heat, visible in the sunlight
700 1292 Dark red
800 1472 Dull cherry-red
900 1652 Cherry-red
1000 1832 Bright cherry-red
1100 2012 Orange-red

C= Centigrade
F= Farenheit "

[gdw]

"A road bike is by its nature very fast going down hill, low rolling resistance and the roads tend to be long grades of incline/decline which mean you have to stay on top of the brakes to keep the speed safe. Mountain bikes have a lot more rolling resistance, and trails generally require you to scrub speed less frequently, and you're not going as fast, so you have to dissipate less kinetic energy."


You need to visit Boulder sometime. Every trip into the mountains west of the city starts with a long climb on pavement and ends with the same. It's pretty easy to duplicate the speeds and braking shown on the video on a mountain bike and an awful lot of riders are using Shimano discs brakes and rotors without the problems shown in the video.

[oldpotatoe]

"A road bike is by its nature very fast going down hill, low rolling resistance and the roads tend to be long grades of incline/decline which mean you have to stay on top of the brakes to keep the speed safe. Mountain bikes have a lot more rolling resistance, and trails generally require you to scrub speed less frequently, and you're not going as fast, so you have to dissipate less kinetic energy."


You need to visit Boulder sometime. Every trip into the mountains west of the city starts with a long climb on pavement and ends with the same. It's pretty easy to duplicate the speeds and braking shown on the video on a mountain bike and an awful lot of riders are using Shimano discs brakes and rotors without the problems shown in the video.

What happened then? Why did they 'fail'?

[gdw]

I don't know what happened but have you seen that occur on their mountain discs? Lots of mountain bikers round trip Walker Ranch and the Flagstaff descent should cause the same problems.

[oldpotatoe]

I don't know what happened but have you seen that occur on their mountain discs? Lots of mountain bikers round trip Walker Ranch and the Flagstaff descent should cause the same problems.

Nope.....why I asked...

Bigger rotors? Able to cool more efficiently/better on MTB system?

sumthin happened..even in German.

[gdw]

Might have been the smaller rotors but a lot of big guys are riding 160s on their mtbs to save weight and not complaining. Maybe the road rotor is a slightly different design or Shimano's trying to increase their aftermarket sales.

[bluesea]

Shimano wet systems work fine with all Alu rotors.

[martl]

Anybody speak German?

http://www.tour-magazin.de/technik/so_testet_tour/video-praxistest-scheibenbremsen/a30097.html

Two things are obvious without words, carbon fork flex, and Ice Tech rotor failure.

Yep. Nothing really that isn't evident from watching the clip. It is a steep, narrow road with tight bends. To simulate an emergency situation, a stop was performed on the less steep, straight end of the road.
In addition to the weight visible in the frame triangle, the backpack also carried some weight.

The front disks inner aluminum part melted and was pressed toward the disk, causing a system failure. The rider says he could pull the lever all through to the handlebar without much effect.


Personally, i can attest both the magazine and the autor, whom i know personally, the utmost integrity.

I have one point of criticism, though: They added additional weight to simulate a heavier rider, but they did this by adding the majority of the weight *inside the frame triangle* which puts the center of gravity way lower than where it would be for a rider of 90kg.
This pushes the point to where the weight distribution is 100% front wheel/0% rear wheel further, allowing more braking, but stressing the material .
I asked the testers how much weight was in the frame and how much was in the backpack. I hope they will answer.

martl (resident german)

[Lionel]

I'm not ready for disc brakes on the Ventoux descent. I've never been close to 100km/h off road. YMMV.

[zap]

I have heard of several tandem teams melting (al inner) Shimano ICE 203 discs last year. ICE discs on our tandem survived many hard braking events and coupled with EBC Gold pads remains my favorite combo.

As I was aware of this potential melting issue for more than 2 years, I was (still am) conservative with our braking on some big multi switchback descents, alternating brake f/r mid straight (longer ones) to scrub some speed before the braking zone(s).

On short descents we never had a problem slamming on the brakes at 50 mph to negotiate a turn on to another road at the bottom.

[ergott]

I asked the testers how much weight was in the frame and how much was in the backpack. I hope they will answer.

martl (resident german)

If you have their ear I would like it if you could ask them some more questions.

Were the pads bedded properly first?

Why were the brakes howling like that before the test even began?

Were they anticipating a problem? They had a second camera man waiting at that spot?

I still have to use my physics and ask why the brake rotors weren't showing any signs of glowing when the melting point of aluminium would result in such. They might not know that answer, but it's a valid question.

Thanks for checking in!

[zap]

I still have to use my physics and ask why the brake rotors weren't showing any signs of glowing when the melting point of aluminium would result in such. They might not know that answer, but it's a valid question.



I think ever higher temperatures allows the aluminum to be extruded from the steel sides easier. Doesn't need to reach melting temps.

The condition of the disc in the Tour video is similar to what I've seen on tandem forums.

[Bostic]

I'm very happy with the performance of the newer design TRP Spyre Mechanical disc brakes on my Volagi Liscio. There is no squealing at all like in the video. The BB7's I originally had on the bike made that horrible sound on any steeper descent and I've taken the bike on every steep climb/descent there is in San Francisco and in Silicon Valley. I'm using the TRP 160mm rotor in front and 140mm in back.

[jamesutiopia]

As the owner of a road-going hydraulic disc equipped tandem who rides in the bay area and Cascades, I am quite familiar with the howl in that video. Happily my rotors don't melt...

[lukasz]

140mm rotors and from the video it seems that rider/backpack alone were 100kg. So how much weight was in the box on the bike? We demand more info. Mooooorrreee!

[ergott]

Video actually looks like 160mm rotors. I have 140s and the only have 4 arms in the spider.

Sent from my DROID RAZR HD using Tapatalk

[saab2000]

Video actually looks like 160mm rotors. I have 140s and the only have 4 arms in the spider.

Sent from my DROID RAZR HD using Tapatalk

You weigh a fraction of the mass they used in the test and you aren't likely to encounter the kind of braking they did in the test. I'd say be happy and enjoy your brakes.

I won't deny I'm very curious to try them out one day. Keep an eye on wear and everything else. You're a pretty detail-oriented kind of guy so I expect you'll have no issues.

It's an evolving technology.

[lukasz]

Good eye, Eric. I assumed 140 because that's the stock size, right?

I'd still like to know more about whether it was 100kg bike/rider or 100 kg rider/backpack and then bike/weight inside triangle.

[martl]

If you have their ear I would like it if you could ask them some more questions.

Were the pads bedded properly first?

Why were the brakes howling like that before the test even began?

Were they anticipating a problem? They had a second camera man waiting at that spot?

I still have to use my physics and ask why the brake rotors weren't showing any signs of glowing when the melting point of aluminium would result in such. They might not know that answer, but it's a valid question.

Thanks for checking in!

I'll ask him as soon as i can.
"Tour" has a reputation for thorough tests (most of the time :D) so i assume the pads were set up and prepared correctly.

I wouldn't read anything into the camera man at the stop. No idea how the shot happened, but if i was to do such a thing, i'd shot the introduction on top, then have the camera crew travel to the finish line, give the rider the "go" and shoot the "final verdict" there. Wouldn't read that much into it.

you are right, that were 160mm discs.

[ergott]

I was doing some googling (a little knowledge can be dangerous). I appears that at elevated temperatures (like 400*C, but even at lower temps), aluminium is more likely to deform for a given strain rate. I think the brakes and outer steel layers of the rotor are acting like forms and squeezing the aluminium without actually melting it. That would account for the lack of discoloration seen while the braking episodes were at their most extreme. It could be that the alloy core will deform and squeeze out at temperatures much lower than 660C.

The good news for me is I ride in situations far less demanding than those tested. If this does indeed prove to be a legitimate issue, I can always switch out the rotors. I've actually thought of moving to a 160mm front if need be. It's just an adapter away from happening.

I will say that for absolute braking force, the 140mm rotors have been more than adequate for my needs right now. I was surprised how well they worked.


source - http://essay.utwente.nl/58200/1/defal_graduatethesis_2002_van_haaren.pdf