Rock & Roll will never die, but rim brakes are on the outs.

[dsut4392]

I don't think the manufacturers will have any trouble getting the weight of disk fitted road bikes down to (and below) the UCI minimum. Reduced material on the rim will more than make up for any extra weight on the disks or forks. Yes disks on road bikes will be standard within a few years. Once the Pro teams start using them it will happen virtually overnight. And personally the sooner the better.

I'm very much pro-disc brake, but your assertion about rim weights is simply incorrect. I doubt you could even reduce rim weight enough to keep angular momentum the same, let alone overall mass. Yes, you'll still be able to build up below the UCI minimum, but that arbitrary limit doesn't apply to most cyclists anyway.

 

[dsut4392]

Be fair, he wasn't aiming to create a strawman - or at least not one that doesn't exist - but rather enjoying the comedic pratfall excellence of a scene written by a Keystone Kops scriptwriter.

The comedy of keystone kops comes mainly from the downright improbability of the plots. In that sense the scene is funny indeed, but when it's put forth as a documentary I find it less amusing...

 

[Bustedknuckle]

I don't think the manufacturers will have any trouble getting the weight of disk fitted road bikes down to (and below) the UCI minimum. Reduced material on the rim will more than make up for any extra weight on the disks or forks. Yes disks on road bikes will be standard within a few years. Once the Pro teams start using them it will happen virtually overnight. And personally the sooner the better.

you must not work on them now, on MTBs...gonna be a comedy when they are 'standard' on all bicycles.

Discs(mechanical) have been around for over a decade..do you mean hydros only? Do you have them on your road bike now?

 

[Boeing]

I don't think the manufacturers will have any trouble getting the weight of disk fitted road bikes down to (and below) the UCI minimum. Reduced material on the rim will more than make up for any extra weight on the disks or forks. Yes disks on road bikes will be standard within a few years. Once the Pro teams start using them it will happen virtually overnight. And personally the sooner the better.

I think its time to clarify terms and definitions.

the weight issue is really specific to the rotor itself. materials are limited and from the years of mountain bike experimentation trial and error, titanium as a weigh saver hasent worked out even with special coatings. unless there is something beyond my level of engineering such as carbon etc.

 

[King Boonen]

I think its time to clarify terms and definitions.

the weight issue is really specific to the rotor itself. materials are limited and from the years of mountain bike experimentation trial and error, titanium as a weigh saver hasent worked out even with special coatings. unless there is something beyond my level of engineering such as carbon etc.

I think they use carbon fibre discs in F1, so I'm guessing the operating temperatures will be much too high for bikes.

 

[StyrbjornSterki]

The future is here. Thirteen disc brake equipped road bikes shown at EuroBike 2013. One of them is a Storck with a claimed weight of 6.3 kg.

 

[kuoirad]

I think they use carbon fibre discs in F1, so I'm guessing the operating temperatures will be much too high for bikes.

Yup.

http://www.formula1.com/inside_f1/understanding_the_sport/5284.html

And the amount of heat they have to get "into" the brakes before they'll actually be useful would not be safe on a bike.

 

[StyrbjornSterki]

I think they use carbon fibre discs in F1, so I'm guessing the operating temperatures will be much too high for bikes.

Yup.

http://www.formula1.com/inside_f1/understanding_the_sport/5284.html

And the amount of heat they have to get "into" the brakes before they'll actually be useful would not be safe on a bike.

It isn't the CF rotors that require all that residual heat, it's the CF rotors used in conjunction with CF brake pads. F1 needs that particular combination because of the extreme range of temperatures their brakes are subjected to. But how often are bicycle brakes asked to slow a 700 kg object by 250 kph in a distance of a 150 meters, 50 times in a period of 120 minutes?

Storck was showing CF rotors at EuroBike as early as 2007. These are branded Carbonicci but I believe they were sourced from Fibre Lyte, one of three companies known to be armpit deep in developing CF road bicycle brakes, along with CarbonTex and Kettle Cycles. Kettle Cycles in particular claims to have tested their CF rotors with sintered metal, semi metallic, kevlar, ceramic, resin and organic pads.

Carbon disc brakes are just like the 12-sp cluster: coming soon to a road bike near you, whether anybody wants them or not.

 

[King Boonen]

Styrbjorn, kettle cycles do not make rotors with carbon braking surfaces, at least nothing on their website indicates they do. I can't find any info on the other two companies in a quick search but I'd guess they don't either.

 

[Boeing]

IS this the story of Johnny Rotten?

 

[avanti]

I think they use carbon fibre discs in F1, so I'm guessing the operating temperatures will be much too high for bikes.

As do aircraft - because weight-wise CF can absorb more energy (BTU/lb). Roughly 3-times that of steel discs.

 

[StyrbjornSterki]

Styrbjorn, kettle cycles do not make rotors with carbon braking surfaces, at least nothing on their website indicates they do. I can't find any info on the other two companies in a quick search but I'd guess they don't either.

Absence of Google-fu is not evidence of absence. All three companies I mentioned have shown prototype CF rotors at different times, and have discussed their development in other forums.

 

[avanti]

Absence of Google-fu is not evidence of absence. All three companies I mentioned have shown prototype CF rotors at different times, and have discussed their development in other forums.

A quick Google search turned up this site
http://www.kickstarter.com/projects/kettlecycles/siccc-bicycle-brake-rotor-silicon-carbide-ceramic

 

[Boeing]

Upon further review of many of the replies here....

"there's more to a picture than meets the eye"

 

[King Boonen]

Absence of Google-fu is not evidence of absence. All three companies I mentioned have shown prototype CF rotors at different times, and have discussed their development in other forums.

Then provide the links fu-master, as everything I can find relies on silicon carbide for the friction required for breaking.

 

[King Boonen]

Perhaps I wasn't all that clear. I do some seriously long alpine descents - 20km+ @ 7% - passes like the Stelvio. Some degree of dragging is inevitable, particularly during back to back turns, even though on-off braking is the preferred and predominant method.

Would you drag both brakes though? I find it almost impossible to believe someone could drag both brakes to the point of failure and not realise it. I'm not sure if it would even be possible with a decently specc'd rotor and calipers.

...it is not uncommon on a really aggressive Alpine descent to stop for a bit to let the rims cool down (and give the forearms a rest ).

You would do the same with disc brakes then. I think the total failure with no indication is unlikely, you would get significant brake fade beforehand. Less forearm pump though with hydraulics

My great fear with hydraulic rim brakes is that the point of failure hits without warning when the brake fluid goes over a certain temperature. That it, frankly, a terrifying thought. I can handle a popped tube from rim-brake overheating, and I can judge modulation degrading as rims heat up, but the thought of suddenly, and without warning, losing all braking power due to hydraulic fluid overheat is making me nervous just typing this.

I'm sure this is Shimano, Sram, Campagnolo etc's biggest fear too and I can guarantee they will be extensively testing them. As I said before, rim brakes and cable brakes can fail as well, with just as catastrophic consequences.

Currently:

- Lightest set up is carbon hoops with rim brakes
- Next is alu with rim brakes
- Heaviest is disc brakes with consequential higher weights in spoke count, fork reinforcement and of course the braking hardware.

There is an inescapable conflict here - the whole point of brakes is to stop and the whole point of a top-end road bike is to go fast particularly up hill where weight matters.

So, in order to enjoy marginal improvements in braking (ie fixing a problem that, as you observe with DA rim brakes, doesn't really exist) the bike gets slower. Or, if you want a crazy light disc set up, you run the risk of overheating and sudden unwarned catastrophic failure of braking function which defeats the purpose of the disc brakes in the first place.

That's why disc brakes on road bikes with not be UCI legal anytime soon.

But that extra weight will not raise the bike above the UCI limit. I know that doesn't apply to most people but if someone is struggling up hills because of the extra 200-300 grams discs are likely to add then they need to train more.

... if I ever get a set of discs, I will probably abuse them to the point of overheating early on - just to see what they do. Sometimes it pays to know what will happen when you exceed the envelope.

Sorry for the heavy edit but this highlights what I said earlier. I can guarantee anyone testing hydraulic disc brakes on road bikes are doing this, probably more intensely than any of us would be able to.

 

[laziali]

You would do the same with disc brakes then. I think the total failure with no indication is unlikely, you would get significant brake fade beforehand. Less forearm pump though with hydraulics

No, the point of the article I originally referenced, where the guy with disc brakes had sudden brake failure at high speed, was that the fail came from the hydraulic brake fluid exceeding a certain temperature. No prior warning for him. Given he's actually had catastrophic and complete disc brake failure on a road descent and none of us have, I putting my faith in his objective report rather than our subjective speculation. PS, here's what he said:

"As we began our descent, it took only a few seconds to get up to speed. Being my first time on this road, I kept light pressure on the levers, dragging my brakes to keep my speed around 30mph on a very curvy, steep road. Coming around a corner, I pulled my brakes a little harder and the levers went to the bar. I held them there. I was still accelerating. In the span of one second, I realized that a) I had no brakes, b) if I kept descending it was only going to get worse, so c) I better crash now and minimize the damage.

Fortunately, I was headed into the side of the mountain rather than off the side. As quickly as I could, I tried to push the bike out from under me and let it ghost ride. I didn’t think about what, exactly, I would do without a bike under me, but I knew I didn’t want to get tangled up in it at 35mph. That’s all I remember until I stopped, lying in a ditch in the fetal position gasping for air.

He then goes own to quote Magura, who have provided him with some advice on the issue:

"What we found with road bikes was that you can generate incredible heat and forces. There are long descents where you’re dragging the brakes for a long time. You have tiny little calipers with very little thermal mass. And they have tiny little pistons that require very little fluid volume. Then you have tiny rotors with virtually no mass that can’t dissipate heat. When you whittle everything down to a super lightweight package, the only place for all that heat to go is the hydraulic fluid, and you can boil it in no time at all. When the fluid boils, it happens instantaneously and it happens right behind the brake pads. As soon as that happens, it introduces air into the system." (My emphasis) http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/

I'm sure this is Shimano, Sram, Campagnolo etc's biggest fear too and I can guarantee they will be extensively testing them. As I said before, rim brakes and cable brakes can fail as well, with just as catastrophic consequences.

You'll be wanting to revisit the famous Ford Pinto court case then before putting your faith in a corporate's sense safety over money http://en.wikipedia.org/wiki/Grimshaw_v._Ford_Motor_Co.

 

[laziali]

Well, here's BikeRadar's view on hydraulics following the launch of Shimano's version:

"There are no two ways about it, a hydraulic road brake system is heavier than a mechanical rim caliper system. Lawrence said Shimano's system adds roughly 300g — not including additional potential weight on the frame and the fork. With Shimano's rim brakes already quite functional, many riders and even many shop owners are asking, what is the point?"

http://www.bikeradar.com/road/gear/category/components/groupset/groupset-road/product/review-shimano-r785-electronichydraulic-system-47604

Couldn't have put it better myself.

 

[BroDeal]

Why were ceramic rims never very popular? They solve most of the issues that people are looking at discs to solve.

 

[42x16ss]

AFAIK fragility was the issue - they were too brittle

 

[hiero2]

Why were ceramic rims never very popular? They solve most of the issues that people are looking at discs to solve.

Interesting - never heard of 'em - I don't keep up with all the new and proposed stuff. But interesting idea. Somebody replied they were brittle - but they are making new ceramics with flex in them. Don't know what they do when they break. Could be nasty edges, maybe not.

However, I would suspect that using aluminum and carbon fiber are still much cheaper alternatives than super-ceramics. Don't know at all - but new technology usually has a high cost.

 

[BroDeal]

AFAIK fragility was the issue - they were too brittle

My set worked great until I crashed them out. I heard some people had issues with the ceramic flaking or peeling off but supposedly Mavic had bad batches.

 

[Moose McKnuckles]

Well, here's BikeRadar's view on hydraulics following the launch of Shimano's version:

"There are no two ways about it, a hydraulic road brake system is heavier than a mechanical rim caliper system. Lawrence said Shimano's system adds roughly 300g — not including additional potential weight on the frame and the fork. With Shimano's rim brakes already quite functional, many riders and even many shop owners are asking, what is the point?"

http://www.bikeradar.com/road/gear/category/components/groupset/groupset-road/product/review-shimano-r785-electronichydraulic-system-47604

Couldn't have put it better myself.

Yep. The point is that Shimano will make more $$ from a more expensive brake set that will make a bike heavier and uglier and provide zero benefit to 99.9999% of cyclists.

 

[winkybiker]

Why were ceramic rims never very popular? They solve most of the issues that people are looking at discs to solve.

My Mavic R-SYS SLR wheels with the "Exalith" hard surface treatment are the best braking wheels I've ever used, wet or dry. Really great in the wet compared to alloy rim surfaces. They need special hard pads, but I've had the same pads on since new, 18 months ago. They squeal like a ******* for the first 300km or so, but are now fairly quiet (pleasant light hum when braking due to the textured surface).

Not inexpensive, though.

 

[laziali]

Yep. The point is that Shimano will make more $$ from a more expensive brake set that will make a bike heavier and uglier and provide zero benefit to 99.9999% of cyclists.

Exactly.

So I rode DA9000 rim brakes for the first time today on alu rims - well, f@ck me, the braking power of DA9000 on alu rims is PHENOMENAL! I had back off the level power a lot to avoid going over the bars.

Why anyone would want more braking power than DA9000 rims brakes is beyond me. Disc brakes on road-bike = solution in search of a problem.