Disc brakes: your greatest dreams, and fears confirmed.

Discuss light weight issues concerning road bikes & parts.

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neeb
Posts: 724
Joined: Tue Jan 27, 2009 8:19 pm

by neeb

Don't know if this has been touched on yet in this thread, but one paradox with disc brakes that I can't get my head around (other than from a marketing perspective) is this:

Practically, the braking advantages of discs are really only in the wet. Yes, I know a lot of people will disagree with that - modulation, confidence when descending even in dry conditions, bla bla bla. But really, modern rim brakes work so well in dry conditions that all of the minor disadvantages of disks (weight, aero, maintenance, complication etc) together vastly outweigh the small braking advantages in the dry. If you think they don't, I would suggest that's down to lack of experience and a false conflation of the lighter feel of disc brakes with actual modualtion and stopping power. And of course, to the extent that rim wear with rim brakes is genuinely something worth worrying about it's really only if you are regularly riding in wet conditions when grit sticks and wears rims down faster.

So... why do so few disc brake road bikes have fittings to accept full mudguards? (I believe you call them fenders in the States). If it's chucking it down and I want to go riding in those conditions I might actually appreciate disc brakes. But I'd appeciate a dry arse even more.. ;-)

by Weenie


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Alexbn921
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by Alexbn921

I live in California and really only ride in the dry. I tend to use my brakes very hard for very short duration. Something I learned road racing cars in college. Rims never had the power to confidently brake at the level of traction. I'm heavy too so that doesn't help either. All of our road either go up or down and are poorly maintaned, so that extra fine control comes in handy.

TheRich
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Joined: Tue Jan 01, 2019 1:36 am

by TheRich

neeb wrote:
Sat Nov 02, 2019 2:48 pm
Don't know if this has been touched on yet in this thread, but one paradox with disc brakes that I can't get my head around (other than from a marketing perspective) is this:

It's easier to understand when you don't start with a false premise or use red herrings.

talltales
Posts: 143
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

neeb wrote:
Sat Nov 02, 2019 2:48 pm
Don't know if this has been touched on yet in this thread, but one paradox with disc brakes that I can't get my head around (other than from a marketing perspective) is this:

Practically, the braking advantages of discs are really only in the wet. Yes, I know a lot of people will disagree with that - modulation, confidence when descending even in dry conditions, bla bla bla. But really, modern rim brakes work so well in dry conditions that all of the minor disadvantages of disks (weight, aero, maintenance, complication etc) together vastly outweigh the small braking advantages in the dry. If you think they don't, I would suggest that's down to lack of experience and a false conflation of the lighter feel of disc brakes with actual modualtion and stopping power. And of course, to the extent that rim wear with rim brakes is genuinely something worth worrying about it's really only if you are regularly riding in wet conditions when grit sticks and wears rims down faster.

So... why do so few disc brake road bikes have fittings to accept full mudguards? (I believe you call them fenders in the States). If it's chucking it down and I want to go riding in those conditions I might actually appreciate disc brakes. But I'd appeciate a dry arse even more.. ;-)
Discs are NOT impervious to rain either. When wet they tend to squeal and loose 1/2 the break power. I now have two TRP equipped road bikes and both have abysmal braking compared to good calipers, in either wet or dry. NOT IMPRESSED.

neeb
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Joined: Tue Jan 27, 2009 8:19 pm

by neeb

TheRich wrote:
Sat Nov 02, 2019 5:27 pm
neeb wrote:
Sat Nov 02, 2019 2:48 pm
Don't know if this has been touched on yet in this thread, but one paradox with disc brakes that I can't get my head around (other than from a marketing perspective) is this:

It's easier to understand when you don't start with a false premise or use red herrings.
I didn't.

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

neeb wrote:
Sat Nov 02, 2019 6:43 pm

I didn't.

You sure did. Certain bikes get hardware for mounting fenders/mudguards. It has nothing to do with whether the frame uses disc or rim-brakes, but the stated purpose of the bike. Is it a road race bike? No provision for mudguards. Is it a true CX bike? No provision for mudguards. Is it a gravel bike? Maaaaybe. Is it a touring bike? Yes, most likely. Etc, etc. You're being even more disingenuous whether intentional or not because wet braking performance is not the only advantage of disc-brakes.

HTH.

neeb
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Joined: Tue Jan 27, 2009 8:19 pm

by neeb

TobinHatesYou wrote:
Sat Nov 02, 2019 7:11 pm
neeb wrote:
Sat Nov 02, 2019 6:43 pm

I didn't.

You sure did. Certain bikes get hardware for mounting fenders/mudguards. It has nothing to do with whether the frame uses disc or rim-brakes, but the stated purpose of the bike. Is it a road race bike? No provision for mudguards. Is it a true CX bike? No provision for mudguards. Is it a gravel bike? Maaaaybe. Is it a touring bike? Yes, most likely. Etc, etc.
Well, that was partially my point, wasn't it? Discs are a poor choice for a pure road race bike. Where they may be a sensible is for a more general purpose / training bike that's going to be used fairly often in wet conditions (i.e. the sort of bike that many of us might want as a winter bike or as a do-it-all road bike if we only have one bike).
TobinHatesYou wrote:
Sat Nov 02, 2019 7:11 pm
You're being even more disingenuous whether intentional or not because wet braking performance is not the only advantage of disc-brakes.
But the other advantages are negligible and outweighed by the disadvantages, as I implied.

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Miller
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Location: Reading, UK

by Miller

neeb wrote:
Sat Nov 02, 2019 7:53 pm
[Discs are a poor choice for a pure road race bike.
It doesn't matter how often you say that, it's still not true. Wins on disc bikes are stacking up in the protour. You may not like that but it's a fact.

neeb
Posts: 724
Joined: Tue Jan 27, 2009 8:19 pm

by neeb

Miller wrote:
Sat Nov 02, 2019 8:31 pm
neeb wrote:
Sat Nov 02, 2019 7:53 pm
[Discs are a poor choice for a pure road race bike.
It doesn't matter how often you say that, it's still not true. Wins on disc bikes are stacking up in the protour. You may not like that but it's a fact.
It would be pretty remarkable if they weren't, given the push to discs.. Still no Grand Tour winners on discs though!

I'm sure there will be sooner or later - not saying that it makes a massive difference (or maybe not even a significant one), it's just not optimal. And it would make a significant difference if the weight limit wasn't being kept unreasonably high to please Specialized etc.

spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

troll gonna troll
2019 BMC TM01 Road UCI config 7.36kg

TheRich
Posts: 828
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

talltales wrote:
Sat Nov 02, 2019 5:40 pm
Discs are NOT impervious to rain either. When wet they tend to squeal and loose 1/2 the break power. I now have two TRP equipped road bikes and both have abysmal braking compared to good calipers, in either wet or dry. NOT IMPRESSED.
Maybe you should try good disk brakes.

TheRich
Posts: 828
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

TobinHatesYou wrote:
Sat Nov 02, 2019 7:11 pm
neeb wrote:
Sat Nov 02, 2019 6:43 pm

I didn't.

You sure did. Certain bikes get hardware for mounting fenders/mudguards. It has nothing to do with whether the frame uses disc or rim-brakes, but the stated purpose of the bike. Is it a road race bike? No provision for mudguards. Is it a true CX bike? No provision for mudguards. Is it a gravel bike? Maaaaybe. Is it a touring bike? Yes, most likely. Etc, etc. You're being even more disingenuous whether intentional or not because wet braking performance is not the only advantage of disc-brakes.

HTH.
That's the red herring.

The false premise is that rim brakes are just as powerful as hydro disks.

Nikoras
Posts: 102
Joined: Thu Sep 26, 2019 1:59 am

by Nikoras

Just to throw another point in here. I ride a Giant Defy and today I was exploring some Connecticut hills. A gravel road caught my eye and I decided "why not" it kind of devolved into some chunkier wetter gravel and mud but I was still able to have a blast on it. Thanks to "current marketing trends" in road bikes with fatter tires and disc brakes I was able to have a fun time doing a bit of offroading on a whim on my mostly road bike. That's worth something to me.

flying
Posts: 2423
Joined: Mon Dec 19, 2005 9:16 am

by flying

Nikoras wrote:
Sat Nov 02, 2019 11:40 pm
Thanks to "current marketing trends" in road bikes with fatter tires and disc brakes I was able to have a fun time doing a bit of offroading on a whim on my mostly road bike. That's worth something to me.
That is good that you feel better exploring that road but we have also been using much skinnier tubulars & rim brakes in races such as Paris Roubaix & worse for over 100 years.

I personally have been smiling a bit at the whole "gravel" movement lately & how they have created that niche needing yet another bike.
Not CX & not Mountain bike mind you but "gravel" :roll:

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

neeb wrote:
Sat Nov 02, 2019 7:53 pm

But the other advantages are negligible and outweighed by the disadvantages, as I implied.

Oh you mean negligible advantages like being able to swap wheelsets between a CX bike, gravel bike and road bike? You mean negligible advantages like never having to worry about exploding tubes or heat related rim failure? You mean negligible advantages like being able to ride carbon rims even in the worst weather? Negligible advantages like different width rims not requiring caliper adjustment? Negligible advantages like a slightly out of true wheel not causing pulsing? Negligible advantages like the option of completely hidden hoses/cabling? Etc, etc.

by Weenie


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