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Why choose disc brakes over rim brakes for a road bike?

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Why choose disc brakes over rim brakes for a road bike?

Old 02-25-19, 01:40 PM
  #126  
Seattle Forrest
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Originally Posted by DavePL View Post
Hi, Yes, I ride mostly on dry days, and don't need all that expensive technology to stop the bike! They wan't you to spend more money on technology that doesn't do anything to make a bike faster.
Let them do something to make the bikes lighter and faster, or less complicated for a change!
Yeah screw stopping, I'm putting my money into a motor. Brakes are for fakes.
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Old 02-25-19, 01:43 PM
  #127  
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Big bike needs big brakes

Originally Posted by ljsense View Post
To me it seems like disc brakes are unnecessary. But they sell so well, so I'm curious why -- why would or did you get road disc brakes? What do you think of them?
And now for something completely different...

In the realm of the custom cruiser & in this case custom e-bike world where a frame alone can weigh over 30lbs. standard rim brakes or (God forbid) a coaster brake is simply wholly inadequate to bring a 80+lbs. finished bike to a halt. In the custom world it's not uncommon to be able to route the cables internally through the frame making for a very clean, uncluttered overall design.


1300W front hub motor laced into 4\" x 26" rim with 150mm disc.

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Old 02-25-19, 02:50 PM
  #128  
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Old 02-25-19, 03:00 PM
  #129  
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I've been riding a disc brake Canyon Endurace CF SL as a versatile road and rails-to-trails bike. Prior to owning the Canyon, I used a cantilever brake Cyclocross bike for the same duty. Both cantilever brakes and disc brakes allow tires larger than 30mm without interference, this is not really possible with short reach brakes found on road bikes. Cantilever brakes are not always the best performers, particularly in the rain. Modern hydraulic disc brakes with through axles are a outstanding all-weather performers with light lever action and superb modulation. Mine have been maintenance free without any adjustments need. Most performance road bikes planned for 2019 will feature disc brakes, the industry is fully behind the technology.

However, I'm not convinced that disc brakes are an advantage over short reach rim brakes if the bike is equipped with smaller tires, is used exclusively on pavement and if wet weather performance is a low priority. While a disc brakes road bike can be light enough for the Tour de France, disc brake systems are heavier than rim brakes. Also, the frame and especially the fork need to be reinforced and stiffened to cope with the loads where the disc brake caliper is installed. Heavier and harsher is not an improvement.
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Old 02-25-19, 03:03 PM
  #130  
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Originally Posted by Cruiser2112 View Post
[left]
...In the custom world it's not uncommon to be able to route the cables internally through the frame making for a very clean, uncluttered overall design.
That cable routing is so clean I can't even see them.
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Old 02-25-19, 03:27 PM
  #131  
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Originally Posted by Seattle Forrest View Post
Yeah screw stopping, I'm putting my money into a motor. Brakes are for fakes.
Derailleurs are for faileures
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Old 02-25-19, 03:47 PM
  #132  
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Originally Posted by daoswald View Post
To eliminate wheel rim side wear-through on expensive rims. Conceivably no need for rim brake surface could allow for reduced rotational inertia/mass.
.
This is most of the reason why disc brakes are pushed by manufacturers.

Everyone wants to ride expensive carbon rimmed wheels, but the manufacturers never truly figured out how to make a durable carbon brake track. They had to fiddle with special carbon resins, specific brake pads etc. etc. and it is a safety concern if / when the rim wears out or gives out because of too much heat build-up on long descents. This is probably why Shimano Dura Ace wheels always had alloy brake tracks with carbon fairings.

So to circumvent the problem, they now use disc brakes. Disc brakes have other benefits of course, but i like the simplicity of a rim brake.
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Old 02-25-19, 05:05 PM
  #133  
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To me it's a no-brainer. I go down some fairly steep hills and disc brakes just provide so much more confidence. Aero/weight are not premium considerations for me though I don't think the penalties for normal road riding are significant.
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Old 02-25-19, 05:09 PM
  #134  
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For what it's worth I just upgraded my 2011 Tarmac frame to a 2019 rim brake frame. I have a bike with disc brakes and yes it provides confident braking. I am confident I can stop with rim brakes too. I don't worry about rim failure - I have never seen a rim failure because of overheating. I kept my rim brakes because I don't want to upgrade my wheels (again) and I don't like the complexity of disc brakes. I think rim brakes will always be available so I'm not worried about obselence.
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Old 02-25-19, 05:13 PM
  #135  
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Quite honestly I just like having them on the bike. The fact that the roadie purists hate them is even more enjoyable to me.

To more of the point of this thread. I sought them out and only considered bikes with disc brakes. To me the added stopping power on long descents was a no brainer.
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Old 02-25-19, 08:56 PM
  #136  
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As a long time rider and now the owner of a disc equipped bike, I think the advantages are: stopping power and rim wear. The disadvantages are weight and feedback. If you are going into a corner with a little wet sand on your tire front tire (and I have many times, once with disastrous results - another story), it's easier to feel the subtle nuances of wheel slip with rim brakes. I like my disc brakes, but it's really easy to grab too much brake.
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Old 02-25-19, 10:39 PM
  #137  
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Why

Originally Posted by daoswald View Post
To eliminate wheel rim side wear-through on expensive rims. Conceivably no need for rim brake surface could allow for reduced rotational inertia/mass.

Better performance for someone doing frequent, extended, intense descents with no potential for overheating a tire.

Greater clearance for wide tires assuming frame can accommodate.

But to some extent they are a solution in search of a problem. I have them on one bike, not on the other, and don't much mind either way.
I never got the point either. I loaded the crap outta my bike and never had overheating problems nor experienced wear problems on rim material. To me it's just a gimmick but I'm a retro grouch so....
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Old 02-25-19, 10:49 PM
  #138  
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Originally Posted by Cycle Tourist View Post
I never got the point either. I loaded the crap outta my bike and never had overheating problems nor experienced wear problems on rim material. To me it's just a gimmick but I'm a retro grouch so....
Do you have much experience with road disc brakes?
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Old 02-25-19, 11:40 PM
  #139  
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Originally Posted by Bikesplendor View Post
The central issue: Trust me, I know what I'm doing,

https://youtu.be/Hd6WfZHY_Cs
One of the most under-rated, under-appreciated, funniest tv shows of all time!
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Old 02-25-19, 11:49 PM
  #140  
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Originally Posted by Elvo View Post
Derailleurs are for faileures
It's failleurs with two "L"s.
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Old 02-26-19, 12:40 AM
  #141  
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Originally Posted by ljsense View Post
To me it seems like disc brakes are unnecessary. But they sell so well, so I'm curious why -- why would or did you get road disc brakes? What do you think of them?
Im betting, in a few years, when road disc pricing come down some, even the cheapest option will be on par or outperform the best ever rim brakes. If you are not familiar with budget hydro brakes, go try a cheap mtb or flat bar fitness bike and you see what Im getting at. Hydro is fundamentally a better technology and its long overdue having it come to road bikes. Net up electronic 105 and tiagra.
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Old 02-26-19, 09:40 AM
  #142  
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Originally Posted by ljsense View Post
To me it seems like disc brakes are unnecessary. But they sell so well, so I'm curious why -- why would or did you get road disc brakes? What do you think of them?
There are a couple of reasons - light weight aluminum rims have quite thin brake surfaces and wear pretty rapidly. There are some "wear holes" that show when you are supposed to replace the rims and on the super lightweight rims they are gone in four months of heavy sports riding.

On the deep aero carbon rims they do have brake pads that have minimal wear on the rims but they too can wear too rapidly and one thing you do NOT want is a tire blowing off of a rim because it has worn too thin to be able to hang together when you hit a bump or are accelerating hard or braking hard.

Disk brakes offer a solution albeit not a very cheap one. But your $1,600 rims can last a great deal longer as you replace three dozen disk brake pads and two sets of disks for a fraction of the cost. I expect to see someone tell me that they don't wear out disk brake pads but in less than 1,000 miles I've had to replace at least one set that I can remember. Hard breaking overheats the disks and literally burns the surface of the brake pads rapidly.
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Old 02-26-19, 09:53 AM
  #143  
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Originally Posted by Racing Dan View Post
Im betting, in a few years, when road disc pricing come down some, even the cheapest option will be on par or outperform the best ever rim brakes. If you are not familiar with budget hydro brakes, go try a cheap mtb or flat bar fitness bike and you see what Im getting at. Hydro is fundamentally a better technology and its long overdue having it come to road bikes. Net up electronic 105 and tiagra.
Disk brakes are a solution to a problem that shouldn't exist. Furthermore they create more problems than they fix. Firstly, mechanical disks do not operate very well, the cable play has you re-adjusting them every other ride. Secondly, hydraulic road levers really are expensive and while they work well, I don't like the idea of a cut line ending my riding day. And they are sloppy to install. Thirdly, On rim brakes most of the stopping forces are placed on the strongest parts of the frame - the top of the fork at the headset bearing and the top of the seat stays near the seat tube. On disk brakes the stopping forces are placed at the very end of the fork with a long lever arm to put pressure against the top of the fork. And BEHIND the seat stay, chain stay intersection. On Carbon Fiber bikes these sorts of concentrated forces on long lever arms are bad news for longevity.
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Old 02-26-19, 09:55 AM
  #144  
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Originally Posted by RiceAWay View Post
I expect to see someone tell me that they don't wear out disk brake pads but in less than 1,000 miles I've had to replace at least one set that I can remember. Hard breaking overheats the disks and literally burns the surface of the brake pads rapidly.
What pads where those?
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Old 02-26-19, 09:57 AM
  #145  
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Originally Posted by Cycle Tourist View Post
I never got the point either. I loaded the crap outta my bike and never had overheating problems nor experienced wear problems on rim material. To me it's just a gimmick but I'm a retro grouch so....
As a tourist you are a hell of a lot more conservative rider. Racers go as fast as they can into corners and then brake very heavily. They buy super lightweight wheelsets and super sticky brake pads. This all adds up to lots of wear on very expensive parts. In cases like this disk brakes have a lot going for them.
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Old 02-26-19, 10:03 AM
  #146  
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Originally Posted by RiceAWay View Post
BEHIND the seat stay, chain stay intersection. On Carbon Fiber bikes these sorts of concentrated forces on long lever arms are bad news for longevity.
On CF bikes, it's very easy to for the manufacturer to compensate for the increased stress.

Most CF road bikes now place the rear caliper on the left chainstay, IN FRONT of the axle.
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Old 02-26-19, 10:28 AM
  #147  
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Originally Posted by Seattle Forrest View Post
So I don't wear my expensive rims out, because they modulate so much better, because it's wet here, to use wider tires, because I don't need rim brakes - do I really want to sacrifice brake quality to save a few hundred grams? Why not only have a front brake for even more weight savings?
I don't want to derail this thread, but what tires are you using?

IIRC, you have Enve SES 4.5 AR Disc wheels, right? I just purchased a similar width Light Bicycle wheelset, and I'm wondering about actual tire widths.
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Old 02-26-19, 10:44 AM
  #148  
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Originally Posted by RiceAWay View Post
Disk brakes are a solution to a problem that shouldn't exist. Furthermore they create more problems than they fix. Firstly, mechanical disks do not operate very well, the cable play has you re-adjusting them every other ride. Secondly, hydraulic road levers really are expensive and while they work well, I don't like the idea of a cut line ending my riding day. And they are sloppy to install. Thirdly, On rim brakes most of the stopping forces are placed on the strongest parts of the frame - the top of the fork at the headset bearing and the top of the seat stays near the seat tube. On disk brakes the stopping forces are placed at the very end of the fork with a long lever arm to put pressure against the top of the fork. And BEHIND the seat stay, chain stay intersection. On Carbon Fiber bikes these sorts of concentrated forces on long lever arms are bad news for longevity.
​​​​​​It's never occurred to me to worry about this. Is there a reason you think a hose is more likely to cut?
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Old 02-26-19, 10:45 AM
  #149  
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Originally Posted by noodle soup View Post
I don't want to derail this thread, but what tires are you using?

IIRC, you have Enve SES 4.5 AR Disc wheels, right? I just purchased a similar width Light Bicycle wheelset, and I'm wondering about actual tire widths.
Right now I've got IRC Roadlights in 28. Very supple. I loved the ride of Pro Ones but they're too fragile for me.

I hope you're loving your new wheels!
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Old 02-26-19, 10:51 AM
  #150  
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Originally Posted by Seattle Forrest View Post
​​​​​​It's never occurred to me to worry about this. Is there a reason you think a hose is more likely to cut?
Discs, man - they'll cut right through their own hoses.
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