Your next road bike: disc or caliper brake

[V12man]

Max stopping power is just before full lock, unless you're riding in snow.

 

Modulation is important. The quickest way for me to stop on a rigid fork is to basically do stoppies: lock, pop up the rear, unlock, repeat. Wash brown pants.

 

With a suspension fork, the technique varies a little because the fork will dive.

 

In cycling, unlike cars or motorbikes, bodyweight and body position is significant. The more you can throw your weight back and down, the harder you can pull brakes before popping up the rear.

Max stopping is at full lock - no question at all about the physics of it - Abs activation always lessens stopping distances quite considerably... the benefit is you have some steering capability and in theory can drive around an obstacle.

 

The effects of weight transfer on the physics of braking are the same on a bike and a car - just on a bike if you get it wrong you are heading for an otb- something that can be done in a vehicle too given some issues with cog heights and roll centers needing to be comparatively higher than normal to be the same as a bike - watch monster trucks and you will see similar handling to a bike - except for the ability to move the cog around using bodyweight as you have on a bike to adjust the front to rear brake balance - but that just enables the rear to brake better instead of its normal distribution.

 

The ability to change the structural physics of a bicycle by moving bodyweight has nothing really to do with disc vs rim brakes - and will have similar effects on either.

 

I still believe that disk brakes are a better solution to bike braking - not a more powerful brake but a more controllable one - with them enabling some future better wheel designs - both functionally and safety wise.

[Mongoose!]

So on what wheel size will a Disc brake works best?

26"    27.5"   or 29"

[V12man]

I can't agree to that.

 

It's very easy to fix a bad rim brake on the fly with an allen key. It's very hard to do that with a disc brake.

80/20 the problem mid.ride will be an out of true rim. How do you fix a buckled rim mid ride? This is not an issue with discs at all unless we are talking crash damage - and rims are much more vulnerable to that than discs themselves.

 

Modern disc setups are super reliable - pretty much set and forget - even on an mtb which is usually exposed to much harsher conditions than a road bike would be.

 

Please don't think I am anti rim brakes at all- I am OK with riding them and I do regularly - but there are few good arguments for riding them when trying to run at the ragged edge of traction compared to disc brakes.

 

I have had the experience of descending the Stelvio pass using rim brakes - not one I wish to repeat.. discs every time for that.

[LOOK695]

Not allowed.

 

Had 4 races this year where people were DQ'ed

Vets or open seeded?

[Knersboy]

Max stopping is at full lock - no question at all about the physics of it - Abs activation always lessens stopping distances quite considerably... the benefit is you have some steering capability and in theory can drive around an obstacle.

The effects of weight transfer on the physics of braking are the same on a bike and a car - just on a bike if you get it wrong you are heading for an otb- something that can be done in a vehicle too given some issues with cog heights and roll centers needing to be comparatively higher than normal to be the same as a bike - watch monster trucks and you will see similar handling to a bike - except for the ability to move the cog around using bodyweight as you have on a bike to adjust the front to rear brake balance - but that just enables the rear to brake better instead of its normal distribution.

The ability to change the structural physics of a bicycle by moving bodyweight has nothing really to do with disc vs rim brakes - and will have similar effects on either.

I still believe that disk brakes are a better solution to bike braking - not a more powerful brake but a more controllable one - with them enabling some future better wheel designs - both functionally and safety wise.

Hmmm, I beg to differ that max braking force is at full lock. At full lock the brake force is a function of the dynamic friction coefficient between the tire and road, as the two surfaces are moving relative to one another. When not at full lock the static friction coefficient is at play as the two surface are not moving relative to one another. The static friction coefficient is always higher than the dynamic friction coefficient. This is why it is more difficult to get an object moving when pushing it over a surface than to keep it moving.

 

https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcSo0ENB2NUMGjvoA5hzw9hfvUxzcV9BiVyrAEq0ITTvciOKlKeW

Edited December 20, 2016 by Knersboy

[Madone69]

Let's all just go back to the simple back pedal brake we started on..problem solved

['Dale]

Okay, okay

 

If Sagaaan uses those sharp ninja stars for braking power, I'll do it too ????

[Rocket-Boy]

Discs would solve an annoyance for me - changing brake pads between alu training wheels and carbon racing ones.

I ride a lot of mtb and I just prefer the feel of discs, I have not ridden a disc equipped roadie but I cant imagine it being that far off.

[SwissVan]

Discs would solve an annoyance for me - changing brake pads between alu training wheels and carbon racing ones.

I ride a lot of mtb and I just prefer the feel of discs, I have not ridden a disc equipped roadie but I cant imagine it being that far off.

Discs make sense for mtb as you generally have steep descents and sharp corners where the power of discs give you an advantage i.e. "late breaking" etc

 

Road racing or riding does not have the same braking requirements as mtb

 

Riding down the Stelvio pass or something similar where you have frequent steep hair pin bends to negotiate..... how often does that happe n in the average cyclists life?

 

But... yes the carbon rim issue is an issue

[TALUS]

Onto my second disc road bike now. Rode my previous racing bike (rim brake) 3 weeks ago. Sold it a week later for less than the value of the Di2 groupset. I am not going back.

[carbon29er]

Discs make sense for mtb as you generally have steep descents and sharp corners where the power of discs give you an advantage i.e. "late breaking" etc

 

Road racing or riding does not have the same braking requirements as mtb

 

Riding down the Stelvio pass or something similar where you have frequent steep hair pin bends to negotiate..... how often does that happe n in the average cyclists life?

 

But... yes the carbon rim issue is an issue

I've never ridden Stelvio. But I do a 1,400 metre climb with 108m ascent at the start of every ride from home. Naturally it's a descent at the end of my ride. With 7 speed humps. With discs I only brake for the stop sign and the humps to wash off some speed. No way I would be happy to do that on rim brakes.

[lukeram]

That is one of the reasons I am thinking of getting a road frame with disc brakes having experienced discs on my gravel bike, even with cable disc brakes.....

 

At this time I am looking at cable disc brakes as I am going to build with Campagnolo

My two cents here- I have a diverge with the tekro mech discs and the braking is really not great - have ordered a sram rival hydro (the set with the clown levers) as have read good things on them.

 

If possible I'd avoid mech discs...

 

And to answer the OP, next road bike will be disc - but only come upgrade time, not rushing out to buy a new one now... 

[rudi-h]

this is much like the debate of whether to buy a 26" or a 29" bike in 2008...

 

clearly rim-brakes are going to win this fight in the long run...  advantage in terms of braking consistency, advantage in terms of rim design etc.

 

so take the plunge and get discs with your next bike, otherwise you'll be no other than "that guy" who still owned a 26" bike in 2016...

[LOOK695]

My two cents here- I have a diverge with the tekro mech discs and the braking is really not great - have ordered a sram rival hydro (the set with the clown levers) as have read good things on them.

 

If possible I'd avoid mech discs...

 

And to answer the OP, next road bike will be disc - but only come upgrade time, not rushing out to buy a new one now...

 

Currently using TRP Spyre on my gravel bike and the braking is more than adequate

[Yusran]

My two cents here- I have a diverge with the tekro mech discs and the braking is really not great - have ordered a sram rival hydro (the set with the clown levers) as have read good things on them.

 

If possible I'd avoid mech discs...

 

And to answer the OP, next road bike will be disc - but only come upgrade time, not rushing out to buy a new one now... 

 

Currently using TRP Spyre on my gravel bike and the braking is more than adequate

 

^Likewise, I have Avid BB7 Road S's on my handbuilt steel gravel/cx/tourer/endural-groad bike and the braking is MORE than adequate.

 

Okay I do use 2 fingers to brake on descents instead of 1 finger like on my MTB, but I'll be upgrading to cable-to-hydraulic disc brakes soon enough just coz I have upgraditis.

 

A well-setup cable disc brake will perform more than good enough for most (bear in mind that a long, fast descent is necessary to bed your discs/pads in or they will lack effectiveness), it's the same with rim brakes really - if they are badly set up you will have no confidence in them. But that goes for everything on a bike actually... your shifting, brakes, setup all need to be done properly.

 

 

PS: I've been wanting disc brakes on a road bike since I started cycling (about 4 years ago) and I wanted this before I even knew they existed. They took so long to get here that I built a drop bar mtb, retro-fitted discs to a cantilever cyclocross bike and finally got my dream bike built by my favorite local framebuilder. I've had too many close encounters riding in the wet with rim brakes, skinny tyres and wheels with spokes on a diet; now I'm riding discs, 32mm tyres and 32-spoke wheels and I can safely say that I'm never going back. This is all my personal preference so no preaching or offense is intended

 

[Fat Boab]

Hmm,

 

So I was going to start a separate thread about the new Roubaix. I borrowed a demo version of this from the Cedar Concept store this last weekend and did about 100 kms on it around the cradle.

 

It was the Ultegra specced one with cable shifters and hydraulic discs and had the hard cartridge in the front shock.

 

Disclaimer: And I am 52 years old (53 in January) and not exactly a race snake (more of a Clydesdale/Percheron). I have an older Roubaix Expert as well, and my Colnago C40 (although the Roubaix is my wife's bike now) so i have some things to compare against. I am a more leisure oriented rider than racer TBH. Mostly 50 to 70 kms in the Cradle twice every weekend and some races. I raced road bikes seriously about 10 to 15 years ago though.

 

But believe me I think this bike is a game changer. This bike is truly a new paradigm and an indication of things to come.

 

Its not the discs or the smoothness that was so apparent. They are nice, and yes the bike is very smooth over broken tar - just like a  silky smooth ride. And no you don't notice any bobbing at all. It just gets on with its stuff. i did notice I was less stiff and sore after 50kms compared to my Colnago C40 (which is very stiff).

 

So a tick for fatigue reduction.  Also a tick for smoothness and comfort - it's a bit higher in the front and its a really comfortable ride - your back isnt too flat. If you want that (and I do).

 

But one thing stood out about it.  its the handling.

 

There have been some articles about it already, but its true. As you now have suspension, the wheels stick like dog poo to a blanket even over rough chattery corners. And that means higher corner speeds and a bike that literally feels like it's glued to the tar, that asks to be thrown around and that inspires confidence in the rider. It handles very neutral, it's not skittish and quick to turn, it just sits very stable and gets on with things. 

 

And if there is one thing that  leads to smile factor it's a bike that does this (at least for me). I was coming in to corners really fast to test it, and it just felt completely solid.

 

Now couple that with the discs and you have a package that can brake better than any rim braked bike and carry much higher corner speed, because it has suspension. This is a light bulb moment on road bikes. The first pseudo suspension road bike that doesn't rob you of power - and its really amazing. It must be a bit like the first crude suspension on early motorbikes - there was no going back (look at MTB).

 

Its also different to the Trek  Domane in that it has vertical compliance not horizontal (which in suspension terms in the holy grail)

 

Even the 25mm tires were able to run at about 7,5 to 8 bar as the suspension is now not in the bigger tires, so no need for 28mm or lower pressures. So less rolling resistance and weight if that worries you.

 

And it accelerates quickly - short sprint efforts were no problem.

 

Its like the one Tread article where the guys observed that South African MTBers are crazy to ride the hard core race oriented XC machines they do - and about 80% of the fields would have a better day if they had a longer travel, slacker bike under them (like the Specialized Epic vs Camber debate).  This bike is the same. 80% of the folks out there should ditch their super rigid carbon road machines for something like this - and they will go a lot faster and also feel a lot better. Its that simple.

 

So no you dont need the discs (I have said that somewhere else on this string) and you can ride any road bike with rim brakes forever, it will do the job.

 

But this bike really does change the landscape going forward.

 

Go and test one - you will be in the order queue as well.

 

PS - I reckon Cannondale are dusting off their old Headshock round about now...

 

You weren't out on this Roubaix this morning in the cradle were you? I saw someone on a disc-equipped, wide-ish tyres, drop bar, similar shape to the Roubaix. Didn't get a close enough look, but was intrigued......