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Disc brake evolution continues

Old 05-13-16, 05:39 PM
  #1  
jmess
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Disc brake evolution continues

Didn't take very long
https://https://www.bikerumor.com/2016/05/13/tred-solves-dangerous-disc-brake-rotor-problem-pro-peloton/
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Old 05-13-16, 05:45 PM
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I am seeing through-axles ... like the WorldTour guys use, right?

Obviously there are solutions, and eventually one will be found ... which allows high-speed wheel changes, and is universal, so the neutral service vehicle doesn't have to carry 300 wheels ... and then, Finally, we can have the no-better-stopping, heavier, un-aero, complicated disc brakes none of the pros have been pining for.
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Old 05-13-16, 06:16 PM
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Waiting for someone to call them dork discs.
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Old 05-13-16, 06:25 PM
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That looks truly awful.
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Old 05-13-16, 06:32 PM
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A solution in search of a problem.

You have a better chance of being killed falling from your bed than of being mauled by a bike disc rotor.
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Old 05-13-16, 06:35 PM
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Those look hideous.
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Old 05-13-16, 06:47 PM
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The only reason to install them is to meet some prescribed need from the UCI so unless any of us are planning on racing UCI sponsored events it should be of little concern to the club rider or touring rider or everyday rider. I never gave it a second thought when I bought my MTB except that I wanted Hydraulic rather than cable operated disk brakes.

To me the issue of additional damage during a crash is not as big a deal as some make it. The big problems in wheel changes and different stopping distances in tight packs. Crit races just magnify those braking distances and road races magnify the tire changes.
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Old 05-13-16, 08:22 PM
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Kind of reminds me of the placebo cross-drilled disk brake rotors some ricers install on their Civics to hide the tiny drums behind their knockoff 17" wheels.
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Old 05-13-16, 10:29 PM
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I'm waiting for air brakes- they offer much more stopping power.
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Old 05-14-16, 05:58 AM
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Originally Posted by Stucky View Post
I'm waiting for air brakes- they offer much more stopping power.
Really???
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Old 05-14-16, 06:20 AM
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Originally Posted by 2 Piece View Post
Really???
Yes.. of course. Whoever above said disk brakes offer more stopping power than rim brakes on road bikes is just wrong. I guess some things will never be put to rest. The limit on stopping a road bike is not the brakes, it's the endo limit and that's somewhere around 0.5 to 0.6 g and determined almost entirely from the tangent of the angle from the front contact point to the center of mass point.

Yes, a parachute or some kind of reverse warp drive thrusters would absolutely get around that limit.
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Old 05-14-16, 06:28 AM
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Originally Posted by Flinstone View Post
Yes.. of course. Whoever above said disk brakes offer more stopping power than rim brakes on road bikes is just wrong. I guess some things will never be put to rest. The limit on stopping a road bike is not the brakes, it's the endo limit and that's somewhere around 0.5 to 0.6 g and determined almost entirely from the tangent of the angle from the front contact point to the center of mass point.

Yes, a parachute or some kind of reverse warp drive thrusters would absolutely get around that limit.
I thought the limit on stopping power on a bicycle was the tires??
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Old 05-14-16, 06:43 AM
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Every advancement have their nay sayers. It boils down to money. Im sure that the wheel mfg are behind the push to ban disc brakes. If a bike has disc brakes, they wont wear out the rims, it is that simple.

The nay sayers alway seems to be against any advancement. I am easily old enough to remember when click shifting came out in the 80s. The nay sayers then said it was unnecessary and that any "good" cyclist doesnt need such a contraption.

And of course it goes further back than that when the old fools of the UCI took money under the table to declare that a recumbent bicycle wasnt actually a bicycle.

The bottom line here is the fact that a rim that doesnt need a brake strip can be made lighter stronger and more aerodynamic. And of course the big plus is the fact the rim doesnt get worn out by the rim brake shoes.
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Old 05-14-16, 07:07 AM
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Originally Posted by rydabent View Post
Every advancement have their nay sayers. It boils down to money. Im sure that the wheel mfg are behind the push to ban disc brakes. If a bike has disc brakes, they wont wear out the rims, it is that simple.

The nay sayers alway seems to be against any advancement. I am easily old enough to remember when click shifting came out in the 80s. The nay sayers then said it was unnecessary and that any "good" cyclist doesnt need such a contraption.

And of course it goes further back than that when the old fools of the UCI took money under the table to declare that a recumbent bicycle wasnt actually a bicycle.

The bottom line here is the fact that a rim that doesnt need a brake strip can be made lighter stronger and more aerodynamic. And of course the big plus is the fact the rim doesnt get worn out by the rim brake shoes.
^I agree with this. Disc brakes are the advancement of technology and it's unstoppable. The comparison to index shifting is very accurate imo, I remember those days too and how much riders initially hated them. As well as other changes that have come along over the years that were disliked at the beginning and eventually accepted as the norm.
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Old 05-14-16, 07:22 AM
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Originally Posted by 2 Piece View Post
I thought the limit on stopping power on a bicycle was the tires??
On road bikes aboslutely not. You cannot lock up a front wheel on smooth dry pavement. Rear wheel's lock, but that's not the tire's fault, in fact it's still from the endo effect. Yes, even applying rear brakes lightens the rear wheel on the road, until it locks and then it can't lighten any more. OK, yes a better rear tire could improve this situation and get you closer to what the front tire can achieve anyway. Any rubber front tire can achieve the endo limit on normal dry pavement though and the rear tire can never achieve better. OK, there is another tire element, overheating. I have heard of tires failing from rims overheating, and I've probably even experienced it, but the tires were old and failing already anwyay. Maybe on huge descents this becomes an issue?

at rydabent: Naysayers.. ha. So understanding the funamendtal, unavoidable, physical limit that is ALREADY reached by rim brakes makes one a naysayer? Do you think a brake system can get around newton's laws? Well, yes you probably do think that. You probably think anyone hung up on such absolute limits set by some guy who died 400 years ago is closed minded and just anti progress. This limit has nothing to do with the brakes themselves and it's very simple physics. Ok, but that's just naysaying.

Now, I never said disk brakes don't have any kind of possible advantage. You ride a recumbent (and I have enjoyed doing so at times too). That's an entirely different story. In all probability your recumbent IS limited by tire friction and not by the endo limit and a disk brake may be an improvement for you. Even that's not clear but for a heavy enough bike, eventually disks will have an advantage. So am I still a "naysayer" or maybe just someone who doesn't ignore facts?

No the comparisson to indexed shifting isn't even slightly analogous. Shifting ease doesn't have a hard-line Newtonian limit.

Last edited by Flinstone; 05-14-16 at 07:28 AM.
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Old 05-14-16, 07:35 AM
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The kind of argument that could carry weight for disks on a road bike would have to be something like "disc brakes can be more finely tuned so that the max applicable braking force is reliably just under the endo limit of the rider, guaranteeing confident application of maximum stopping force without actually reaching an dangerous endo." I'm not making that argument, I'm just saying that's the kind of argument I'd have an open mind toward, not "they achieve higher stopping power", which, on a road bike, is just wrong.
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Old 05-14-16, 08:26 AM
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Originally Posted by Flinstone View Post
You cannot lock up a front wheel on smooth dry pavement.
Yeah you can. Try harder.

You might not want to lock up the front wheel or else you'll have to deal with the impending doom of flying over the handlebars, but you can totally lock the front wheel.
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Old 05-14-16, 08:32 AM
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Originally Posted by SpeshulEd View Post
Yeah you can. Try harder.

You might not want to lock up the front wheel or else you'll have to deal with the impending doom of flying over the handlebars, but you can totally lock the front wheel.

No you can't. Unless you're sliding sideways too or it's not really solid pavement or you're bouncing, any case you aren't getting more stopping force than 0.6 g. It's IMPOSSIBLE. The coefficient of friction of rubber on concrete is well upwards of 0.7 g. The tangent of the angle between your center of mass and the front contact point is about 0.6 or less. That means when stopping force exceeds 0.6 times mg, then the forward pitching torque of braking exceeds the downward pitching torque of gravity, and you're going flying... It's really quite simple.

It's also really a moot point if your traction happens to be less than that (and on dry pavement it certainly is NOT less than that) because either way... you can't stop with more than 0.6 g. PERIOD. No brake in the world or open minded progress can change that in the geometry of present road bikes.

ANyway, when I'm flying over the handle bars after applying front rim brakes I'm supposed to "try harder?".

Last edited by Flinstone; 05-14-16 at 08:51 AM.
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Old 05-14-16, 08:52 AM
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Originally Posted by Flinstone View Post
No you can't. Unless you're sliding sideways too or it's not really solid pavement or you're bouncing, any case you aren't getting more stopping force than 0.6 g. It's IMPOSSIBLE. The coefficient of friction of rubber on concrete is well upwards of 0.7 g. The tangent of the angle between your center of mass and the front contact point is about 0.6 or less. That means when stopping force exceeds 0.6 times mg.. the net toque on your bike about the front contact point, has just reversed from being in a downward rotational sense, to an upward one... and you're going flying... It's really quite simple.


It's also really a moot point if your traction happens to be less than that (and on dry pavement it certainly is NOT less than that) because either way... you can't stop with more than 0.6 g. PERIOD. No brake in the world or open minded progress can change that in the geometry of present road bikes.

ANyway, when I'm flying over the handle bars I'm supposed to "try harder?".
Well your equations are all good if you lived in a perfect world, moot if you do not. What is the coefficients on wet asphault or wet concrete? What about cobble stones? Is the concrete textured or is it worn smooth? Is the asphalt worn as well? Physics is kind of a neat science, but not always applicable. Bumble bees should not fly, but they do.
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Old 05-14-16, 08:53 AM
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Originally Posted by Flinstone View Post
No you can't. Unless you're sliding sideways too or it's not really solid pavement or you're bouncing, any case you aren't getting more stopping force than 0.6 g. It's IMPOSSIBLE. The coefficient of friction of rubber on concrete is well upwards of 0.7 g. The tangent of the angle between your center of mass and the front contact point is about 0.6 or less. That means when stopping force exceeds 0.6 times mg, then the forward pitching torque of braking exceeds the downward pitching torque of gravity, and you're going flying... It's really quite simple.

It's also really a moot point if your traction happens to be less than that (and on dry pavement it certainly is NOT less than that) because either way... you can't stop with more than 0.6 g. PERIOD. No brake in the world or open minded progress can change that in the geometry of present road bikes.

ANyway, when I'm flying over the handle bars I'm supposed to "try harder?".
You said "you cannot lock up a front wheel" - I believe what you're trying to say is, you cannot skid a front wheel, which you probably still can if you have your weight far enough back.

But trust me, you can totally lock up the front wheel. I have enough collarbone injuries to prove it.
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Old 05-14-16, 08:59 AM
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What is usually meant by locking is when brake pressure(edit, brake friction really of course) exceeds road friction and the wheel becomes welded (locked) to the break caliper.. breaking loose from the road and sliding.. This absolutely does NOT cause endos.. in fact, in loose or wet pavement where this can happen it prevents endos. But again, either way, the max deceleration is the endo limit. 0.6g or less.

Last edited by Flinstone; 05-14-16 at 09:57 AM.
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Old 05-14-16, 09:02 AM
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I think what you mean by "locking" is that AS you endo, if you somehow manage to rotate up at the same speed as the wheel that your brake calipers could also grab and track with the rotation of the wheel. .. or maybe that the wheel stands in place while you rotate over it? Neither of those actually exactly happen but it could seem that way.

Anyway, in cars, when people talk about locking the wheels, do they not mean when the wheel stops rotating and thus skids? Isn't that why anti-lock brakes are called anit-"lock". I do believe we had a miscommunication, but I also believe I used the correct term.

But what we're still left with no disagreement on is that the endo limit is the hardest you can brake, and rim brakes achieve that on road bikes for riders in normal weight ranges at least. So nothing can brake harder.

Last edited by Flinstone; 05-14-16 at 09:38 AM.
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Old 05-14-16, 10:00 AM
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Marketing is an important part of the function of equipment sponsorship Deals in Pro Cycling.

Remains to be seen if the Patent Application will Go, since they had disc guards over Moto Cross Bike discs long Ago.

Last edited by fietsbob; 05-14-16 at 10:16 AM.
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Old 05-14-16, 12:52 PM
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Originally Posted by 2 Piece View Post
I thought the limit on stopping power on a bicycle was the tires??
Originally Posted by Flinstone View Post
On road bikes aboslutely not. You cannot lock up a front wheel on smooth dry pavement. Rear wheel's lock, but that's not the tire's fault, in fact it's still from the endo effect. Yes, even applying rear brakes lightens the rear wheel on the road, until it locks and then it can't lighten any more. OK, yes a better rear tire could improve this situation and get you closer to what the front tire can achieve anyway. Any rubber front tire can achieve the endo limit on normal dry pavement though and the rear tire can never achieve better. OK, there is another tire element, overheating. I have heard of tires failing from rims overheating, and I've probably even experienced it, but the tires were old and failing already anwyay. Maybe on huge descents this becomes an issue?

at rydabent: Naysayers.. ha. So understanding the funamendtal, unavoidable, physical limit that is ALREADY reached by rim brakes makes one a naysayer? Do you think a brake system can get around newton's laws? Well, yes you probably do think that. You probably think anyone hung up on such absolute limits set by some guy who died 400 years ago is closed minded and just anti progress. This limit has nothing to do with the brakes themselves and it's very simple physics. Ok, but that's just naysaying.

Now, I never said disk brakes don't have any kind of possible advantage. You ride a recumbent (and I have enjoyed doing so at times too). That's an entirely different story. In all probability your recumbent IS limited by tire friction and not by the endo limit and a disk brake may be an improvement for you. Even that's not clear but for a heavy enough bike, eventually disks will have an advantage. So am I still a "naysayer" or maybe just someone who doesn't ignore facts?

No the comparisson to indexed shifting isn't even slightly analogous. Shifting ease doesn't have a hard-line Newtonian limit.
Yes, the stopping power is (often) limited by the "endo effect", but this limit ultimately depends on the tires. So, 2 Piece is essentially correct.
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Old 05-14-16, 01:32 PM
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I'm familiar with scientific notation, but this thread is mostly "scientific notions."

Regardless, I absolutely LOVE disc brakes. On my Roam 2, on my Roubaix SL4 Disc, and on both my SUV's!
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