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One Man’s View Of Disc Brakes

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One Man’s View Of Disc Brakes

Old 08-21-19, 12:09 PM
  #101  
Seattle Forrest
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Originally Posted by rodey View Post
Yes, and that was a terrible analogy.

Your analogy was seatbelt or no seatbelt. On bikes, it's not disc brakes or no brakes.
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Old 08-21-19, 12:12 PM
  #102  
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Originally Posted by Seattle Forrest View Post
Girls?
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Old 08-21-19, 12:30 PM
  #103  
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The question as to the relative merits of disc beakes vs. pointy beakes is best answered by comparing two representative species: the spoonbill stork (disc beake) and the heron (pointy beake). In each case the beake performs the same primary function: food gathering.

The question is: which is more efficient? Will spoonbills eventually abandon their disc beakes in favour of pointy beakes, or will a bird like the Blue Heron eventually adopt disc beakes? Of course we won't know the answer for millenia, but a significant question it remains.

The spoonbill stork (genus platalea; various species), as we all know, has a beake that is well adapted to performing well in wet conditions (shallow, muddy waters), where it uses its 'spoon' first to muddy the waters, so to speak, and then to filter out, trap, and consume the tiny creatures it stirs up.

Now, the great blue heron (Ardea herodias) is of course a bird of a very different feather. Its primary diet consists of fish, frogs, small mammals and the like which it commonly spears with its pointy beake and then swallows.

What, then, can we infer from the rather obvious continued survival of the two about the relative merits of disc vs. pointy beakes? Well, it is not unreasonable to suggest that each is well-adapted to its primary function: to obtain food.

That said, ornithological debates on interwebz discussion forums suggest that enthusiasts will not rest content until one side or the other 'winz', with either Disc Beakeists or Pointy Beakeists emerging triumphant.

Last edited by badger1; 08-21-19 at 03:46 PM.
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Old 08-21-19, 01:33 PM
  #104  
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Originally Posted by badger1 View Post
The question as to the relative merits of disc beakes vs. pointy beakes is best answered by comparing two representative species: the spoonbill stork (disc beake) and the heron (pointy beake). In each case the beake performs the same primary function: food gathering.

The question is: which is more efficient? Will spoonbills eventually abandon their disc beakes in favour of pointy beakes, or will a bird like the Blue Heron eventually adopt disc beakes? Of course we won't know the answer for millenia, but a significant question it remains.

The spoonbill stork (genus platalea; various species), as we all know, has a beake that is well adapted to performing well in wet conditions (shallow, muddy waters), where it uses its 'spoon' first to muddy the waters, so to speak, and then to filter out, trap, and consume the tiny creatures it stirs up.

Now, the great blue heron (Ardea herodias) is of course a bird of a very different feather. Its primary diet consists of fish, frogs, small mammals and the like which it commonly spears with its pointy beake and then swallows.

What, then, can we infer from the rather obvious continued survival of the two about the relative merits of disc vs. pointy beakes? Well, it is not unreasonable to suggest that each is well-adapted to its primary function: to obtain food.

That said, ornithological debates on interwebz discussion forums suggests that enthusiasts will not rest content until one side or the other 'winz', with either Disc Beakeists or Pointy Beakeists emerging triumphant.
Winner!
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Old 08-21-19, 02:52 PM
  #105  
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Originally Posted by WhyFi View Post
I had a squeal a couple weeks ago; my rotor was evidently contaminated while sending a wheel off to be rebuilt. It was a matter of minutes to pull the wheel, wipe the rotor, pull the pads and sand them on a diamond plate (though a piece of sand paper on a kitchen counter would work just as well), and re-install. The process was certainly no worse than cleaning metal shards out of rim brake pads.

Why not replace the caliper with the same model - not available?
Not readily available. I couldn't find a quickly available source so went with the newer model not realizing the hydraulic connection was different or I realized it but thought they would ship the necessary connecting hardware with the caliper. In any case, I think using hydraulic disc brakes in the rain is worthwhile but I wouldn't bother for dry weather bikes. I sanded my discs which got rid of the squeal for a week or so but now it's back. Have a new rotor which I'll try next and hopefully that will be the end of the squeal. The squeal does work better than a bell for alerting pedestrians that I'm near which is an unexpected benefit.
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Old 08-21-19, 03:30 PM
  #106  
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Originally Posted by WhyFi View Post
I had a squeal a couple weeks ago; my rotor was evidently contaminated while sending a wheel off to be rebuilt. It was a matter of minutes to pull the wheel, wipe the rotor, pull the pads and sand them on a diamond plate (though a piece of sand paper on a kitchen counter would work just as well), and re-install. The process was certainly no worse than cleaning metal shards out of rim brake pads.
You don't have to go through the bedding-in process after that?
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Old 08-21-19, 03:33 PM
  #107  
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Originally Posted by tyrion View Post
You don't have to go through the bedding-in process after that?
Yeah, you do - diminished braking until they bed back in. Very noticeable the first ride, but now that I think about it, I didn't notice it thereafter.
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Old 08-21-19, 03:34 PM
  #108  
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I don’t sand pads; I cook them in a gas flame for 20-30 seconds. Ten with a propane torch would do. It has never failed for me.
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Old 08-21-19, 03:42 PM
  #109  
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Hey, if you like Discs - here is a new pair. https://www.bikeforums.net/21084590-post1.html
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Old 08-21-19, 03:49 PM
  #110  
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i think my view of disc brakes is that they seem cool but i won't get them because the bikes that don't have them are cheaper
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Old 08-21-19, 04:09 PM
  #111  
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I'm surprised there are people trying to say discs are easier to maintain or it's on par...

IME, it's extremely rare to find a problem in a rim brake system that's hard to solve, and there's no way I could say that about discs.

Pads rubbing? True the disc... Still rubbing. Maybe it's the caliper? Oh look, someone shattered one of the ceramic pistons, there we go. New caliper. Oh wait, still rubbing. Hey, I guess the piston was damaged by someone trying to force the caliper open further than it goes, because it can't be adjusted not to rub, because the frame company couldn't be bothered ensuring the mount was square. Which I can't fix properly, because my boss is too much of a tightarse to buy the tool for it. What fun.

Rotor squealing? Clean it, clean the pads. Still squealing? Replace the pads, clean the rotor again. Still squealing? Damn, the rotor is contaminated. New rotor, clean the pads. OMG, still squealing, because it's basically a result of the geometry of the system and you've gotta just cross your fingers it isn't plagued by squeals. Yay.

Then there's bleeding... Anyone run into mysterious dramas with that bloody palaver? What joy. Oh, and have fun catching the cancer from SRAM systems.

But hey, if you wear out rims from riding in the muck, maybe the potential hassle is worth it. Don't get me wrong, many disc bikes are hassle free, but if one decides to give you a hard time... Much potential.

Last edited by Kimmo; 08-21-19 at 04:16 PM.
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Old 08-21-19, 04:56 PM
  #112  
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Originally Posted by Kimmo View Post
I'm surprised there are people trying to say discs are easier to maintain or it's on par...

IME, it's extremely rare to find a problem in a rim brake system that's hard to solve, and there's no way I could say that about discs.

Pads rubbing? True the disc... Still rubbing. Maybe it's the caliper? Oh look, someone shattered one of the ceramic pistons, there we go. New caliper. Oh wait, still rubbing. Hey, I guess the piston was damaged by someone trying to force the caliper open further than it goes, because it can't be adjusted not to rub, because the frame company couldn't be bothered ensuring the mount was square. Which I can't fix properly, because my boss is too much of a tightarse to buy the tool for it. What fun.

Rotor squealing? Clean it, clean the pads. Still squealing? Replace the pads, clean the rotor again. Still squealing? Damn, the rotor is contaminated. New rotor, clean the pads. OMG, still squealing, because it's basically a result of the geometry of the system and you've gotta just cross your fingers it isn't plagued by squeals. Yay.

Then there's bleeding... Anyone run into mysterious dramas with that bloody palaver? What joy. Oh, and have fun catching the cancer from SRAM systems.

But hey, if you wear out rims from riding in the muck, maybe the potential hassle is worth it. Don't get me wrong, many disc bikes are hassle free, but if one decides to give you a hard time... Much potential.
Before this post, I always thought you were a rock solid mechanic.

#Disappointed

Last edited by noodle soup; 08-21-19 at 05:00 PM.
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Old 08-21-19, 05:25 PM
  #113  
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Originally Posted by noodle soup View Post
Before this post, I always thought you were a rock solid mechanic.
Care to fill me in?


...Are you saying my basic premise, that discs can be way more of a PITA, is incorrect? Or was it something else?

Last edited by Kimmo; 08-21-19 at 05:40 PM.
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Old 08-21-19, 05:37 PM
  #114  
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Putting the subject aside, the guy's a total wanker.
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Old 08-21-19, 05:57 PM
  #115  
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Originally Posted by Kimmo View Post
Care to fill me in?


...Are you saying my basic premise, that discs can be way more of a PITA, is incorrect? Or was it something else?
Not really? If the bike is maintained properly on a regular basis by either a competent mechanic or a home mechanic it requires very little work. Clean the caliper of build up, push the pistons in and out a few times each and wipe them down to make sure they aren't sticking, occasionally true a rotor or use icetech rotors that almost never go out of true. Contamination isn't really that big of a concern, and bleeding is a simple process that takes like 2x to get the hang of. For shimano you can go like 3-4 years even without a bleed as the mineral oil doesn't absorb water. Overall if you include total time over the life of a rim brake bike that used in the rain, the time spent works closer than you'd expect if you factor in a relace of a rim hoop that involves tensioning and/or replacing spokes.
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Old 08-21-19, 06:10 PM
  #116  
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I got confused and thought this was the tubular thread.

I have discs on the MTBs, and the cxes, mostly rim on everything else and tandem is rim front, disc rear.

To the tandem. I put a TRP hybrid on there and it is very smooth. I like PowerCordz vs steel cable feel, but the brake is a good option.
I also went with a 160mm rotor from PowerTap and it had something very big before.
I also have the rotor farther from the seat stays/mount as I am neutrally dished on a narrower hub. Spacing is 145mm wide, too wide IMO, but I bought the bike used.

So anyway...
On hard (HARD) stopping now, there is deformation. Maybe the seat stays flex, maybe as the mounts are farther they flex. That takes the brake out of alignment during braking. Of course rim brakes move too and they will rid up the brake track. But I could always (dry road conditions) stand the tandem on the front wheel with rim brakes before the new ENVE serrated things. I don't much care, as I rarely brake, but if stopping hard were important I'd go back to smooth tubular rims and rim brakes. As is, I very much like the rear disc as a drag brake. When I need to stop fast, I use the front and although not as good as a smooth sided rim, it works.

I don't ride in the rain.
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Old 08-21-19, 06:57 PM
  #117  
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Originally Posted by redlude97 View Post
Not really? If the bike is maintained properly...
I'm not saying they are a PITA, I'm saying they can be. They can **** you up the wall way harder than any cable rim brake system, if you're unlucky. Part of it is because hydraulics, and part of it is because disc, particularly the problem of squealing which is can be time-consuming and sometimes futile to address.

Most folks won't have issues, but as a mechanic I saw the bikes that had them. Usually a simple fix, but the scope for complications is huge.
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Old 08-21-19, 07:56 PM
  #118  
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Originally Posted by Kimmo View Post
...particularly the problem of squealing which is can be time-consuming and sometimes futile to address...
I've never had hydraulic disks, but it has always been my suspicion that they would be just as susceptible to incessant squealing as my mechanical disks since I hear them squealing all the time when I ride with guys who have them. I think some people either don't notice or it doesn't bother them. Thanks for clearing that up.
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Old 08-21-19, 08:05 PM
  #119  
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Originally Posted by kingston View Post
I've never had hydraulic disks, but it has always been my suspicion that they would be just as susceptible to incessant squealing as my mechanical disks since I hear them squealing all the time when I ride with guys who have them. I think some people either don't notice or it doesn't bother them. Thanks for clearing that up.
Many of us have given up trying to get rid of the squeal. Others have simply run out of budget.

We just live with it, pretend it doesn't actually happen and hope nobody complains.


-Tim-
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Old 08-21-19, 09:22 PM
  #120  
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Speaking of squeal - I have fond memories of Mafac Racers in the days when we used the Mafac pads. You had some control of squeal on setup. I loved it when the squeal was acceptable for routine stops, but loud for really hard ones. Great tool for riding in Boston. When a driver pulls a typical Boston stunt, I'd hit the front brake extra hard. Every head within a block would turn. I'd point at the car. Every eye would follow my point. The squeal brings the driver out of his stupor. He looks up and finds everybody looking at him. Driver slinks off like a guilty dog that's been caught. Fun.

Ben
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Old 08-21-19, 09:25 PM
  #121  
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Originally Posted by rodey View Post
Yes, and that was a terrible analogy.

... On bikes, it's not disc brakes or no brakes.
In Portland, it is often brakes (discs or otherwise) or no brakes.
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Old 08-21-19, 10:20 PM
  #122  
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Originally Posted by 79pmooney View Post
Fun.
Yeah, if the squeal is optional, it's more of a feature than a bug.
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Old 08-22-19, 12:16 AM
  #123  
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Originally Posted by SundayNiagara View Post
I asked the owner of the LBS here in Hialeah, (Leon) who's been in biz for more than 50 years and his answer was: If you plan on riding in wet weather, disc brakes are superior. If not stick with rim brakes. I did.
Both are good but i've ben riding disk for years so that's what I stuck with.
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Old 08-22-19, 01:01 AM
  #124  
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Originally Posted by bruce19 View Post
putting the subject aside, the guy's a total wanker.
100%
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Old 08-22-19, 01:07 AM
  #125  
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Originally Posted by TimothyH View Post
Many of us have given up trying to get rid of the squeal. Others have simply run out of budget.

We just live with it, pretend it doesn't actually happen and hope nobody complains.


-Tim-
...or you could use resin pads.
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