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

[hiero2]

Except how often do you slow down from 60-0 on a typical road descent?
The rotors can take the heat just fine, I've seen my discs glowing red on night rides, without loss of brake function. Plus you're assuming the rims are metal rather than carbon - these may have higher mass, but are very poor conductors resulting in most of the thermal load remaining at the brake track, negating the argument of higher mass.

The pad material is what allows discs to work when hot. Early auto discs had brake fade when hot. But the heat on a disc is nowhere near the problem, imo, as heat buildup on a rim, due to tire issues. So I'm inclined to dismiss concerns about heat buildup on rotors. It would be easier to counter brake fade than a blown tire.

 

[laziali]

@Hiero2



Overheating always gets brought up but it's just not going to be an issue. Yes, the discs are smaller than the rims but they also aren't as well insulated and the dissipate heat much better. They also don't dissipate heat into the inner tube (if you are using them). Over-heating of the oil is unlikely and bent rotors due to heat is extremely difficult to believe. One mountain biker I know is also a power lifter so really does weigh about 300lbs, he's never bent a disc through breaking and he rides downhill as well as trails.
...

Now if the UCI could stop it's silliness and in-fighting they could get on with approving them for road use.

You might want to do some research before saying overheating is not an issue. How would you feel if someone took your "advice" as being correct and committed their safety to disc brakes on a long mountain road descent only to find out what this guy did? http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/

 

[avanti]

It hasn't happened in MTB discs, why do you think adding the much smaller road segment will induce some sort of wheel/hub 'standards?
...............................

If the Pro Tour ever adopts disc brakes I can imagine the teams wanting a standard size so that their riders could use neutral support wheels when needed.

 

[biker jk]

Those are mechanical calipers that are being recalled.

Yes I know. They are disc brakes with a problem.

 

[winkybiker]

Yes I know. They are disc brakes with a problem.

Yes, but the problem is related to pad adjustment, which is a completely different process (with these mechanical disc systems) to that associated with hydraulics. Hydraulic discs have their own problems (and advantages), but this recall isn't evidence of any of those.

 

[Moose McKnuckles]

I routinely ride my Moots Psychlo-X with TRP mag cantis on mountain bike trails with no problems. Braking is great. I use my Ksyrium SL wheels with 35 mm tires.

I run hydraulics on my Spark, which work great. Discs on road bikes are a bit on the ugly side, not to mention the weight penalty.

Moreover, not sure the manufacturers have quite figured out the effects of heat buildup on the fork.

 

[King Boonen]

You might want to do some research before saying overheating is not an issue. How would you feel if someone took your "advice" as being correct and committed their safety to disc brakes on a long mountain road descent only to find out what this guy did? http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/

You might want to read what you actually link to. He used brakes developed for cyclocross, with stupidly lightweight rotors and an adaptor for a cable pull system rather than a proper hydraulic brake lever. He then proceeded to drag both brakes as he was going down hill. He also did the install himself. Sorry he was hurt but this was the fault of the installer picking completely inappropriate parts for the job.

I'm sure you can read the comments section, where one commenter notes he has had no pro lens with discs so far but has had many problems with rim brakes including snapped cables, failed pads and loss of rims structural intensity. So maybe you should do some research before assuming one article counts for absolutely anything.


Back to the real discussion. Weight penalty. How much are your bikes under the current UCI limit? I'm guessing the extra weight is probably only going to take it up to that, if a little over if you are racing. If you're not, I can't see a couple of hundred grams being that much of a deal breaker?

 

[Bustedknuckle]

You might want to read what you actually link to. He used brakes developed for cyclocross, with stupidly lightweight rotors and an adaptor for a cable pull system rather than a proper hydraulic brake lever. He then proceeded to drag both brakes as he was going down hill. He also did the install himself. Sorry he was hurt but this was the fault of the installer picking completely inappropriate parts for the job.

I'm sure you can read the comments section, where one commenter notes he has had no pro lens with discs so far but has had many problems with rim brakes including snapped cables, failed pads and loss of rims structural intensity. So maybe you should do some research before assuming one article counts for absolutely anything.


Back to the real discussion. Weight penalty. How much are your bikes under the current UCI limit? I'm guessing the extra weight is probably only going to take it up to that, if a little over if you are racing. If you're not, I can't see a couple of hundred grams being that much of a deal breaker?

Worked on a Storck the other day, 12.5 pounds, SR EPS, Lightweights...a race bike. If wet discs were available, he would have had them, race bike used by a non racer. Kinda like that goofy Subaru WRX with the great big rear spoiler and paddle shifters, so he can trundle on down to the grocery.

Wet discs are coming, and those who ride for their 25 miles on their less than UCI weight bike on sunday will get 'em.

Racing this and that..Ducati superbike with traction control, with lights and a license plate or a Monster?

It'll happen, it makes no sense. I see those who rave about $150 tubular tires on their bike they ride 2 times a week, 25 miles per pop, in the dry..but they gotta have wet discs..

 

[Moose McKnuckles]

Honestly, I hate to be a grouch here, but I really don't see much benefit for 99.9% of riders from having road discs.

Plus, that's just what racing needs. Overheated discs in a pile-up. Sounds like a great idea. Let's bring back the old Spinergy wheels while we're at it, and every race can be like Hunger Games. You win if you survive.

 

[kuoirad]

Plus, that's just what racing needs. Overheated discs in a pile-up. Sounds like a great idea. Let's bring back the old Spinergy wheels while we're at it, and every race can be like Hunger Games. You win if you survive.

I can't understand why you're making that sound like a bad thing...

 

[42x16ss]

Worked on a Storck the other day, 12.5 pounds, SR EPS, Lightweights...a race bike. If wet discs were available, he would have had them, race bike used by a non racer. Kinda like that goofy Subaru WRX with the great big rear spoiler and paddle shifters, so he can trundle on down to the grocery.

Wet discs are coming, and those who ride for their 25 miles on their less than UCI weight bike on sunday will get 'em.

Racing this and that..Ducati superbike with traction control, with lights and a license plate or a Monster?

It'll happen, it makes no sense. I see those who rave about $150 tubular tires on their bike they ride 2 times a week, 25 miles per pop, in the dry..but they gotta have wet discs..

You just described 90% of the cycling community here It's a matter of time before all the middle age freds start switching.

I've found a total of 2 bunch rides that go further than 60km in 10 months and the only club racing is masters (and I'm not 35 yet )

Oh, and everyone only rides at race pace!

 

[Bustedknuckle]

Honestly, I hate to be a grouch here, but I really don't see much benefit for 99.9% of riders from having road discs.

Plus, that's just what racing needs. Overheated discs in a pile-up. Sounds like a great idea. Let's bring back the old Spinergy wheels while we're at it, and every race can be like Hunger Games. You win if you survive.

Big pile up, and trying to find the right wheels, with discs..140, 160? Lined up? rubbing rotors? Gonna be comedy central.

 

[dsut4392]

Big pile up, and trying to find the right wheels, with discs..140, 160? Lined up? rubbing rotors? Gonna be comedy central.

That old straw man must be getting pretty tired by now.

First point, if you're running disc brakes, it's much less likely you'll need to take a spare wheel to ride away from that pile up. Unless you have a puncture, your wheel being out of true matters far less than with rim brakes. You could easily ride a wheel with multiple broken spokes until your team car pulls up with a spare bike.

Second point, it may be true that mtb has not adopted a standard size disc, but there has been absolutely no incentive to do so. MTB isn't a team sport, and doesn't have pits or neutral (or team) service vehicles out on course to give up a spare. So why would you need to run the same size disc as another guy?

Once disc brakes become uci legal for road racing, they would be mad not to adopt a single size, most likely 160mm. Neutral service may as well make every wheel both disc and rim brake compatible, so you will just have the same problem that exists now with cross compatibility between campy/Shimano/SRAM 10 and 11 speed etc. Just go to 135mm rear dropout spacing at the same time

FWIW, Even with the proliferation of rotor sizes and multiple mount 'standards' I can't think of a single mainstream brake caliper released in the last 5 years or more that won't fit a normal "post mount" (originally Manitou post mount IIRC) without adapters and work correctly with a 160mm rotor. Post mounts for other ice rotors do exist, but if you're using one you'll already know.

 

[deboat]

Honestly, I hate to be a grouch here, but I really don't see much benefit for 99.9% of riders from having road discs.

Plus, that's just what racing needs. Overheated discs in a pile-up. Sounds like a great idea. Let's bring back the old Spinergy wheels while we're at it, and every race can be like Hunger Games. You win if you survive.

Why would the brake rotors be hot or even warm when there is a pile up crash? You have to brake a lot riding down a mountain to get the temperatures you are talking about to cause skin burn. There are never pile up crashes after a long mountain decent.
Next thing will be is that teeth are banned on the big ring so it won't cause injuries in case of a crash.!

 

[Moose McKnuckles]

Why would the brake rotors be hot or even warm when there is a pile up crash? You have to brake a lot riding down a mountain to get the temperatures you are talking about to cause skin burn. There are never pile up crashes after a long mountain decent.
Next thing will be is that teeth are banned on the big ring so it won't cause injuries in case of a crash.!

Have you ever ridden disc brakes? Your post suggests not. There are many braking opportunities when the rotors heat up. One crash and suddenly riders are all getting tattoos of rotors.

 

[laziali]

You might want to read what you actually link to. He used brakes developed for cyclocross, with stupidly lightweight rotors and an adaptor for a cable pull system rather than a proper hydraulic brake lever. He then proceeded to drag both brakes as he was going down hill. He also did the install himself. Sorry he was hurt but this was the fault of the installer picking completely inappropriate parts for the job.

I'm sure you can read the comments section, where one commenter notes he has had no pro lens with discs so far but has had many problems with rim brakes including snapped cables, failed pads and loss of rims structural intensity. So maybe you should do some research before assuming one article counts for absolutely anything.


Back to the real discussion. Weight penalty. How much are your bikes under the current UCI limit? I'm guessing the extra weight is probably only going to take it up to that, if a little over if you are racing. If you're not, I can't see a couple of hundred grams being that much of a deal breaker?

Have another read, and also elsewhere (Google is your friend). You will find that the critical difference is that in MTB and cyclocross, braking is short and sharp. On major alpine road descents there is much more dragging and heat build up. Those of us who spend quite a lot of time on alpine descents know all about heat build up. That is why we generally use alu rims and employ on/off braking techniques.

There is zero chance that I, or a number of other serious roadies I have spoken with, would rely on disc brakes in hilly road terrain. Also, they are much heavier and require a substantially greater number of front-wheel spokes which slows down acceleration.

 

[King Boonen]

Have another read, and also elsewhere (Google is your friend). You will find that the critical difference is that in MTB and cyclocross, braking is short and sharp. On major alpine road descents there is much more dragging and heat build up. Those of us who spend quite a lot of time on alpine descents know all about heat build up. That is why we generally use alu rims and employ on/off braking techniques.

There is zero chance that I, or a number of other serious roadies I have spoken with, would rely on disc brakes in hilly road terrain. Also, they are much heavier and require a substantially greater number of front-wheel spokes which slows down acceleration.

Well both the bold bits show disc brakes would work perfectly well, they already fit your braking techniques.

I drag my brakes all the time as I'm rubbish, particularly on trails I don't know, I only run 160mm rotors and I've never experienced high brake fade. I regularly hit 40mph (65kph) on long descents. All brakes can fail, particularly when used wrong and applied in the wrong situation,taking one example from the internet is not a good representation, particularly when the equipment being used is unsuitable to the task.

The bit in italics is worth discussing. Much heavier? How much? 2.5 pounds? because that's how much busted knuckle had to play with on the Storck build he mentioned. Also the spokes, how much research has currently been done by road manufacturers on wheels for disc brakes? Not much I'd guess. So while this may be the case at the moment I'd think they will make fast progress when disc brakes become more prevalent.

As an aside, 650b seems to be taking over mountain biking at Eurobike. Not many mountain bikers want it, or believe it will give much benefit, but it's happening. You could draw similar parallels with disc brakes on the road.

 

[King Boonen]

20 spokes on a mavic crossmax slr, that's 4 more than Dura-ace c50? And that's a wheel designed to take a bit of a beating.

 

[Bustedknuckle]

Well both the bold bits show disc brakes would work perfectly well, they already fit your braking techniques.

I drag my brakes all the time as I'm rubbish, particularly on trails I don't know, I only run 160mm rotors and I've never experienced high brake fade. I regularly hit 40mph (65kph) on long descents. All brakes can fail, particularly when used wrong and applied in the wrong situation,taking one example from the internet is not a good representation, particularly when the equipment being used is unsuitable to the task.

The bit in italics is worth discussing. Much heavier? How much? 2.5 pounds? because that's how much busted knuckle had to play with on the Storck build he mentioned. Also the spokes, how much research has currently been done by road manufacturers on wheels for disc brakes? Not much I'd guess. So while this may be the case at the moment I'd think they will make fast progress when disc brakes become more prevalent.

As an aside, 650b seems to be taking over mountain biking at Eurobike. Not many mountain bikers want it, or believe it will give much benefit, but it's happening. You could draw similar parallels with disc brakes on the road.

Agree..aimed directly at smaller riders who swoon over 29ers, but are too short to get a useable frame.

Big depends. I know of more than a few downhillers who want nothing but 26 inch..the way they gotta throw the thing around. 29er way too big..a 2.4 tire on a 650b is the same diameter of a 29er 2.2 tire...no thanks but giant in 2014..no mas 26 inch MTBs...

 

[Moose McKnuckles]

I finally went the 29er route this year, after being VERY skeptical. I was super happy with my Scalpel 26er, but decided to go with the Scott Spark 29er.

Honestly, it's been absolutely superb. The only downside I've seen are on sharp switchbacks. On technical stuff, having a 29er is like cheating. Reminds me of my Turner 5-spot. Would run over anything.

 

[laziali]

Well both the bold bits show disc brakes would work perfectly well, they already fit your braking techniques.

I drag my brakes all the time as I'm rubbish, particularly on trails I don't know, I only run 160mm rotors and I've never experienced high brake fade. I regularly hit 40mph (65kph) on long descents. All brakes can fail, particularly when used wrong and applied in the wrong situation,taking one example from the internet is not a good representation, particularly when the equipment being used is unsuitable to the task.

The bit in italics is worth discussing. Much heavier? How much? 2.5 pounds? because that's how much busted knuckle had to play with on the Storck build he mentioned. Also the spokes, how much research has currently been done by road manufacturers on wheels for disc brakes? Not much I'd guess. So while this may be the case at the moment I'd think they will make fast progress when disc brakes become more prevalent.

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.

With rim brakes on alu rims, I can feel when they are starting to get too hot, with modulation in particular vulnerable to change. That gives a sense of proximity to brake/rim/burst tube failure, and 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 ).

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.

 

[Moose McKnuckles]

Just curious. Has anyone measured the weights of aluminum wheels and rim brakes vs. carbon wheels and wet discs?

Honestly, my DA 9k brakes and Mavic Rsys SL wheels brake as well as discs. And I ride my MTB more than all my road bikes combined.

 

[laziali]

Just curious. Has anyone measured the weights of aluminum wheels and rim brakes vs. carbon wheels and wet discs?

Honestly, my DA 9k brakes and Mavic Rsys SL wheels brake as well as discs. And I ride my MTB more than all my road bikes combined.

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.

 

[hiero2]

Big pile up, and trying to find the right wheels, with discs..140, 160? Lined up? rubbing rotors? Gonna be comedy central.

That old straw man must be getting pretty tired by now.

. . .

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.

. . .

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.

The first-hand anecdote you linked to earlier was interesting, but as also pointed out up the thread, the author has no one to blame except his mechanic and his driver, and since he was his own mechanic . . . and the driver . . .

One of the first things I was ever taught about driving was not to ride (drag) the brakes. Same held true on motorcycles, and bicycles, for pretty much the same reasons. Dragging brakes leads to brake failure.

I have experienced brake fade - on a sports car and a bicycle. The car had front disks. The bike only had rim brakes. I hadn't thought about the possibility of an "instant" brake failure - one without warning. All the brake fade I've ever experienced, I knew it was happening. But, I will admit, your comment made me think for a second. The only brake fade I have experienced with disc brakes was on a robust system, with plenty of rotor and stocky metal housing for the hydraulics. Not the small systems for bikes, and not that ridiculously minimalist rotor the guy in the anecdote used. What were they thinking when they designed that? Not about stopping power. But maybe the hydraulic bits are small enough so that you could experience a complete loss of braking without warning due to overheating. I haven't the faintest idea at the moment. But 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.

 

[benlondon]

Disk weight not a problem

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.