[Closed] Road discs - A bit of a random musing....

They're not sanctioned for race use yet.

They're not sanctioned for race use yet.

And what tiny % of road bikes get raced?

It sure why not but it's pleasing to see road bikes at eurobike with hydro discs. Very surprised not to see one from trek though.

Why doesn't this seem to be happening at all in the road world? OK, so brake/frame design might preclude it in some cases, and perhaps it's a weight thing, but surely it makes sense for many/most bikes?

who makes discs, who doesn't, so new no one actually nows what the standards are, re rear hub width. Lots of Roadies not convinced, nowhere near the same level of upgraditist. ( except wheels and things that make you go fast)

Discs still banned on race bikes so no point.

Can you really see the average [s]golfer[/s] new roadie having uneccessary lugs for discs on their bikes?

Good Lord no.

They want to look exactly like that Bradley Cavendish as they parade round the latest Spurtive, throwing gel wrappers at sheep.

And what tiny % of road bikes get raced?

Generally technology trickles down from the top models and dictate the current fashion.

Discs won't be mainstream until racers use them.

Disc won't be mainstream until racers use them.

To counter that, in the early days of MTB discs, racers were vehemently against them, it was recreational/trail riders who drove it primarily. Helped in part by the huck-it years of DH loonz, I suppose. Either way, I don't believe it was racing that drove the demand. (Was in the bike trade at the time, I should add!)

Rusty...LOLercrafts at your post, you cheapskate Carradice must-have! 😛

Mountain biking was anti-establishment in it's early, pre-middle aged it manager, days. Cycling isn't.

I have discs on my road bike by-the-way.

And what tiny % of road bikes get raced?

Sportives are races, right?

They were very obviously a step forward in mountain biking

"Look how I come to stop...with no sphincter clasping moments"

no need on a roadie when as Rusty points out: you're doing 10mph (at best*)

*as an aside, if you are going to go [i]that[/i] slowly, please be a good chap and try not weave quite so very much....)

[url= http://reviews.roadbikereview.com/eurobike-2013-gallery-13-disc-equipped-road-bikes ]Eurobike 2013 road disc gallery[/url]

EDIT: just some pictures...not trying to make any point at all 🙄

throwing gel wrappers at sheep.

Hahaha!

You'd be annoyed if tubeless rims came round at the same time disc brakes went mainstream wouldn't you? Would mean you'd be stuck with discs only when you could have justified discs AND a new wheelset to the missus.

Not required...ride smooth, look ahead and brake light.

Boxfish, rather missing the point here, I'm talking about non-disc bikes being made "disc ready". And yes, I get the "no standards" thing, but I believe SRAM and Shimano are both on the same hub/rotor mounting standard, Campy as well, perhaps. (Am willing to be proved wrong, of course!)

Disc ready would be low end bikes, if it happened.

No-one on expensive machinery would tolerate the sight of unbolted brake bosses or the sight / weight of a rim with a braking surface being used with a disc brake system.

I still just don't see the point, unlike offroad there's no mud. Fine on a winter bike for day after day in the rain, but I just don't see the point on a 'raceing'*, calliper brakes have enough power to throw me over the bars (and it's not like arm pump is an issue either), so why try harder?

They were very obviously a step forward in mountain biking

"Look how I come to stop...with no sphincter clasping moments"

Thank god Avid came along and brought back the whole will they/wont they feature with the juicy's/elixirs.

You'd be annoyed if tubeless rims came round at the same time disc brakes went mainstream wouldn't you? Would mean you'd be stuck with discs only when you could have justified discs AND a new wheelset to the missus.

Pretty much all wheels seem to be tubeless now?

*ok, hardly any bikes are raced, but then neither are many cars, but people still buy mx-5's.

Im with haze on this one, theres less of an advatage on the road. Braking is generally a failure best avoided at all costs.

I've been riding a disc'd road bike for the last 3 years, its ok but nothing to write home about, the main advantage is that the rims don't get covered in rim/brake paste in the wet.

My view:
1. The benefit of discs on a road bike compared to well set-up cantis is less obvious than the move from V's to discs on MTB - whether we need discs or not is not a conversation I've ever had with any of my clubmates - we're quite happy with what we've got, it all works fine. Same with electronic shifting. Even the most kit-obsessed are quite happy with mechanical.
2. Weight matters on a road bike. Lots.
3.

No-one on expensive machinery would tolerate the sight of unbolted brake bosses or the sight / weight of a rim with a braking surface being used with a disc brake system.

^like

aesthetics matters on a road bike much more than MTB

Edit: I've answered my own question haven't I. Anything that would look out of place in a 100 year old photo breaks the aesthetic.

Perhaps another issue is that disc brakes on road bikes require a disc specific fork. On mountain bikes this is not such an issue, but on a road bike, beefing up the fork to maybe run discs is not yet at the stage where it's considered an OK thing to do.

The other issue that I would be concerned about is that the contact patch on road tyres is pretty easy to overwhelm with a more powerful brake; crap (in comparison...) road brakes are well matched with small contact patches and slick tyres. Stick super brakes on and you transfer the weakest link to the tyre rather than the brake/tyre combo.

I think discs will take over, but other than the wearing out your rims and black brake mess, they will not be as much of a performance advantage as in mountain biking.

When racing, we used to run the rear brake set super slack, so that panic grab in the middle of a bunch didn't wear a flat spot on your £40 tyre on the rear...

[img][url= http://farm6.staticflickr.com/5456/9646027301_a147e95ff7.jp g" target="_blank">http://farm6.staticflickr.com/5456/9646027301_a147e95ff7.jp g"/> [/img][/url] [url= http://www.flickr.com/photos/56594563@N07/9646027301/ ]image[/url] by [url= http://www.flickr.com/people/56594563@N07/ ]tangwyn[/url], on Flickr[/img]

I'm running cable actuated hydros on my cx bike, I likes them. Reckon it will come eventually on the pro peloton.

tang - Hy/Rd's? where d'ya get 'em?

Unless you're a fool, you want to be able to stop properly.

Weight?
Not an issue for the majority of us who don't race.
Those anally retentive weight weenies who care enough will just spend yet more money in order to compensate, or stick with calipers.
No problem.

Aesthetics?
You got used to compact frames, metal wheels, cables instead of rods, hydroforming, bladed spokes etc etc.
You'll live.

Roadie Culture?
Oh please give it a rest, you're all as gadget obsessed as the next bloke.
You all spout on about tradition and 'honesty' from the titanium railed saddles of your carbon hyperbikes. 😀

Tyres?
Yep, Crikey has a point.
I'll give it 5 years before the first bicycle ABS 🙂
The rest of us can have wider, comfier tyres.
Yes, I said COMFIER.
The traditionalists can flagellate themselves with a worn out chain when they get home so they can ensure that they suffer properly, as is their wont.

Bring on the discs!

Sparkle- The hyrds were a industry gift I guess. I've been running them all summer and I'm very pleased. Bring on the filth....in a couple of months please!

I stop just fine with my rim brakes cheers Rusty 🙂

On a cx bike I get it.
Mud and filth, wider tyres etc.

On a road bike really non fussed. I can easily lock and slide my 23s down a dry road on budget dual pivots and loss of bite in the wet isn't an issue as there is less grip anyhow! As noted above a stronger and stiffer fork n not good for comfort.

I was an early ish disc brake user on the mtb. Anyone remember the rockshox cable actuated hydraulic discs?

Er, I didn't say you couldn't. 🙂

Mine aren't bad.
But I'd not say no to more power, increased modulation and better control.

Would you?

Oh, and I wonder how easy it is to lock up a road tyre on tarmac compared to an MTB tyre on dirt?
MTB riders seemed to get used to the extra power quite quickly, didn't they?

I'll give it 5 years before the first bicycle ABS

Do keep up at the back, there...

Brovedani ABS system, c.1995, IIRC.

[img] [/img]

However, for this;

You all spout on about tradition and 'honesty' from the titanium railed saddles of your carbon hyperbikes.

[img] [/img]

The other issue that I would be concerned about is that the contact patch on road tyres is pretty easy to overwhelm with a more powerful brake

I've been running BB7s on my work bike for 10 years now. All year, all weather commuting, and some fully loaded touring in the big mountains. I still haven't experienced this problem...

For utility road bikes, discs are practical; consistent braking in all weathers, if your wheels take a beating a minor wobble is not an issue, and you can avoid grinding your rims away with road muck and salt in the winter. I think we will see more and more utility/touring frames with disc fittings.

For competition road racing bikes, a good set of side pulls on alloy rims will brake just as effectively as discs. I guess braking on carbon rims is not as good, but the performance loss probably isn't enough to make discs compelling, given the disadvantages (weight, aerodynamics, cost and complexity). That might change if the sponsors decide to push them in a big way, because the pros ride whatever they are paid to ride (see image above) and new road tech will trickle down.

I think there will be an increasing number of disc equipped sportive bikes for riders who want something practical and are not wannabe racers.

Oh, and I wonder how easy it is to lock up a road tyre on tarmac compared to an MTB tyre on dirt

With a decent dual pivot brake? Very easy indeed.

Think of the wheel rim as a very big disc...

more power, increased modulation and better control

But still all being done through that tiny contact patch at 100 psi.

The other issue which I suspect is only just being thought of in the 'industry' is that currently, people can trash a set of wheels in a couple of years or so, and go out and buy the next big thing. Stick discs on, and no one is wearing wheels out...

For utility road bikes

They're not selling utility road bikes, they're selling the dreams of middle aged men who watch the Tour...

There is an aerodynamic advantage too. The caliper can be made small and compact due to greater power so it can tuck in behind the fork and probably faired in, the disc itself has a very small frontal area so negligible drag, the forks can be better aerodynamically optimised without the need for callipers, and wheel rim profiles can be better aerodynamically optimised without the need for a braking surface.

Now, one often overlooked advantage of discs is that the rim can be built to just be a rim, not a braking surface AND a rim. As such, you can theoretically, build a better, lighter, more aero rim. Which is a win.

Would you?

At the expense of a whole new bike? There's enough power/modulation with rim brakes, so that's a very expensive upgrade for very little gain. I'd use them if they were there, but I don't want/need them for the sake of having them.

I'll give it 5 years before the first bicycle ABS

The rest of us can have wider, comfier tyres.
Yes, I said COMFIER.

tang - I'm also interested in the Hy-Rds, because I find the BB7s are a bit fiddly to adjust, and don't stand up well to winter weather.
I guess you won't have had a chance to give them some proper abuse with this summer's weather, but does the construction look like it will stand up well to salt/grit/winter muck?

I find my road bikes with 23mm tires perfectly comfy as they are TBH, except for riding P-B obviously when 28s are good.

crikey - Member
With a decent dual pivot brake? Very easy indeed.

The other issue which I suspect is only just being thought of in the 'industry' is that currently, people can trash a set of wheels in a couple of years or so, and go out and buy the next big thing. Stick discs on, and no one is wearing wheels out...

thisisnotaspoon - Member
We're discussing braking? What's tyre size got to do with it?

Not required...ride smooth, look ahead and brake light.

There's a lot of truth in this - you simply don't brake as often on a road bike, so more power/modulation etc isn't a solution to any relevant problem...

My summer bike's 4 years old, been ridden 50-100 miles most weeks from May-Sept in that time and still has original brake blocks...

For commuting they can be a good idea - I had Hope Minis on my Roadrat, but for most road riders they're not a solution to a problem. On MTB, they were...

Might buy a new fork one day when they're properly sorted, so I can have a front disc. Back, meh

(though obviously the industry will have moved on 2 steps in fork standards by then and I won't be able to anyway)

Having badly scored a front rim after some tiny metal road debris got stuck to my brake pad in the damp I'm all for discs.

As such, you can theoretically, build a better, lighter, more aero rim.

Go on....

The tyre width dictates the rim width, so how are we going to see a more aero rim?
Lighter, I agree with, but lightness in rims is all a bit 'rotating weight' which has been shown to be far less important than cyclists assume.
Better? In what way?

Given the amount of time that mountain bikes have used discs, I see very little innovation in rim design, they just stopped machining brake tracks, which is hardly the great leap forwards...

I like discs on any bike for one main reason: I am not deliberately wearing out a key structural element of the bike. A lot of the engineering of the rims goes in to mitigating this fact so the at the rims end up doing 2 key jobs.

I know that the stresses involved in braking have to be sorted elsewhere, but I just like the idea of separating these two issues. I have to admit I have just seen the ultimate lightweight brakes: a french kid on a racer with no brakes other than putting his flip flop coated foot on the the rear tyre. That is true minimalism.....

At the lower end of the price scale, the STIs are close to the most expensive part on a road bike, frame and wheels included. Your upgrade path needs to leave the levers alone otherwise you might as well change the whole bike. Pomp/Kaffenback, Tripster and RoadRat, any others been successful offering either/or?

isn't a solution to any relevant problem...

Here's one.

Having badly scored a front rim after some tiny metal road debris got stuck to my brake pad in the damp I'm all for discs.

See also, stronger lighter rims, better wet weather braking, less wheel wobble worries, etc.

Carbon rims seem to be getting more and more popular but braking performance is not great . Disc brakes solve that one at a stroke . You can save weight at the rim where it affects performance most , you can make the rim more aerodynamic . Anybody with MTB disc brakes will know that apart from outright power and consistant performance the other advantage is that you can brake with the wheel just not quite locking up , you just don't get the same feedback with road caliper brakes especially with carbon rims . People spend thousands of pounds on road wheels , disc brakes will mean they get to wear out slower .

I can easily lock and slide my 23s down a dry road on budget dual pivots

Really? On a dry road, you'll go over the bars before the front wheel starts to slide.

But it still takes 2 or 3 years to wear out a road rim. Cyclocross will trash them in a winter, but the longevity in road riding is not as pressing an issue as it seems.

I suspect that as with wheel size, we will be led up the garden path by manufacturers who have invested in this, but I also suspect that the timescale required for the change in attitude will prove a problem.

I already run discs on my commuter/trainer.
I currently run a Giant TCR Advanced as my good roadie but my next carbon roadie will have discs, which I'll buy/build over the winter. People can bleat on about rim brakes being fine - you can keep them. I'm going discs.

You can save weight at the rim where it affects performance most

you can make the rim more aerodynamic

you can brake with the wheel just not quite locking up , you just don't get the same feedback with road caliper brakes

Yes, you do.

disc brakes will mean they get to wear out slower

Which means people will buy fewer wheels, which is not a good thing for wheel makers.

Now, one often overlooked advantage of discs is that the rim can be built to just be a rim, not a braking surface AND a rim. As such, you can theoretically, build a better, lighter, more aero rim. Which is a win.

not really though, brake tracks are almost an afterthought on carbon rims anyway, so yes you might save a bit of weight but a 50mm deep rim still has to have enough carbon to work.

Where disks make sense is on fast commuters, and i would wonder if the correct answer is drum brakes not discs?
Dynamo on the front, drum brakes back, disk front. (only because you can't have everything in the front hub, or have a dynamo in the bottom bracket?) maybe a hub gear on the back, belt drive etc.

The reality is that my next road bike will have discs, my next mtb will probably be 650b. This is nothing to do with what i want, but what will be available. When will i change my bikes? not for the foreseeable, they both work. End of the day, bikes don't really matter, if your unfit your unfit, legs matter more than any a bike.

Which means people will buy fewer wheels, which is not a good thing for wheel makers.

and the biggest gripe i have with discs, they rub, they ting, they are never quiet, changing the wheel is always a faff! so much other crap going on with the mtb i don't care, but the road bike. It is almost silent, I run a chorus rear hub and the clicking on that is loud enough thankyou very much. Would never use hope hubs on the road bike because they are far to noisy even though i use them on the mtb without issue.

This argument was had when disc brakes first appeared on MTBs though. Maybe not quite as prevalent since it was early days of the internet forum but who remembers all the pages of letters to MBUK saying:
7-speed is fine, 8-speed will just clog up with mud
then later:
8-speed is fine, 9-speed will just clog up and the chains are narrower so they'll all break...

And:
cantis stop me just fine, V-brakes are just a fad
followed a few years later by
V-brakes stop me just fine, discs are heavy/complex/just a fad/will need bleeding every week.

Exactly the same here.
To be honest I suspect the main reason behind the disc brake thing on road bikes is that the manufacturers are waiting to see which brake system takes off (is it Di2 + hydro, SRAM hydro...?) and there simply not being enough disc brake stock to kit out everything at the moment.

There's absolutely no need for them, that's why they've never been pushed.

If your road brakes are rubbish, get some better pads or calipers. Job done. I've never felt underbraked on a decent road bike. Disks are for muddy conditions or places where you brake a lot.

crikey - Member

You can save weight at the rim where it affects performance most

, no, it doesn't.

you can make the rim more aerodynamic

How?

you can brake with the wheel just not quite locking up , you just don't get the same feedback with road caliper brakes

Yes, you do.

disc brakes will mean they get to wear out slower

Which means people will buy fewer wheels, which is not a good thing for wheel makers.
Posted 4 minutes ago # Report-Post

Well in my world losing rotating weight is better than losing static weight , if you are really pedantic the tyre is further from the rim therefore will have the most effect .

You can build more aerodynamic rims because you don't have to build in a braking surface .

You are obviously a riding god with unbelievable skills , for the rest of us mere mortals discs have more feedback .

Since disc brakes became the norm on MTBs wheel manufacturers haven't been closing down in droves , perhaps the industry sometimes does things to give riders a benefit not just the balance sheet .

 

How often do you brake on a road ride or race? I think I've ridden races where I haven't braked at all, bit different from mtbing.

Other issue for pros is speed of wheel change which is worse with discs.

I can see hydraulics making sense for commuting but cable operated are sh*t.

This argument was had when disc brakes first appeared on MTBs though. Maybe not quite as prevalent since it was early days of the internet forum but who remembers all the pages of letters to MBUK saying:
7-speed is fine, 8-speed will just clog up with mud
then later:
8-speed is fine, 9-speed will just clog up and the chains are narrower so they'll all break...

and how many people UPGRADE the bike, how many just buy a new bike and get what they are given?

I keep checking the Upgrade bikes website but they're still showing the Hy-Rd's as Back Order. I'll be putting them on my Whyte Saxon Cross as soon as they're available, the current BB7's are OK but as said above a bit of a fiddle I could do without. Next years Saxon Cross is spec'd with Hy-Rd's as standard.

And when will people understand that good brakes are about modulation not power. 🙄

You can build more aerodynamic rims because you don't have to build in a braking surface .

but you can't, look at a 50mm rim now make it more aerodynamic, the rim is still there, the size is the same, the tyre require the same fitment...

Since disc brakes became the norm on MTBs wheel manufacturers haven't been closing down in droves , perhaps the industry sometimes does things to give riders a benefit not just the balance sheet .

Rigida went pop... and what has happened to Sun, Araya, weinmann etc still around granted but a few changes.

You are obviously a riding god with unbelievable skills , for the rest of us mere mortals discs have more feedback .

decent rim brakes are better than discs, when set up well and not covered in crap, so mtb, cx perfect market, road....

And when will people understand that good brakes are about modulation not power.

and the Centaur brakes i have on the road bike are fine in that regard. decent pads, huge 622mm rotor, great for heat dissipation, no risk of aluminium cored disc melting.

Well in my world losing rotating weight is better than losing static weight , if you are really pedantic the tyre is further from the rim therefore will have the most effect .

If you search out the considered opinion on this, rotating weight is the same as weight. It doesn't matter if it spins, it's still weight so it's ability to rotate doesn't matter.

You can build more aerodynamic rims because you don't have to build in a braking surface .

No.
If you make an aero wheel, it will have a flat surface that brakes can act on.

You are obviously a riding god with unbelievable skills

Yes, I am.

perhaps the industry sometimes does things to give riders a benefit not just the balance sheet

You're so far out in the Elephant grass with this one, that you'll never ride home... It's an industry, they're not your friends.

Example: Shimano HG cassettes; they realised that people were turning the single cassette sprockets around to extend the life of the drive chain, so made them into UG sprockets and fixed them onto spiders...

Hands up those who have actually ridden road bikes with disc brakes and would willingly give them up?

as dibbs said, its modulation and brake lever feel that makes the difference with hydraulic (and on TT bikes, the ability to have tight cable routing, although as yet I've not seen a disc TT bike, only the magura RS8s), as well as wet weather performance.

I've ridden all the main systems on the market (calliper, BB7, TRP hydro, SRAM hydro, shimano hydro) and given that I don't race, if i were to buy a new road bike, it'd have discs.

they have far better modulation, complete 1 finger braking whatever the conditions and however hard you have to brake. they allow you to brake far later into corners, which means you go faster. its the control of the braking which is so much better.

i can't see the UCI allowing them in racing any time soon though, thanks to safety fears. they'll be the reserve of grand fondo/sportive riders imo. nowt wrong with that though.

at the end of the day, it's just like wheel sizes. if you don't like it, don't buy it... it's just a bike at the end of the day and not worth getting knickers in a twist about.

[img][url= http://farm8.staticflickr.com/7429/9314529677_51da535a27.jp g" target="_blank">http://farm8.staticflickr.com/7429/9314529677_51da535a27.jp g"/> [/img][/url] [url= http://www.flickr.com/photos/56594563@N07/9314529677/ ]Hyrd[/url] by [url= http://www.flickr.com/people/56594563@N07/ ]tangwyn[/url], on Flickr[/img]
Here's mine. They are quite well built, if a little bulky(no weight penalty over bb7). Work a treat with the ultegra levers I have, very easy to set up, modulate nicely. I did one long road ride in the rain on cow shitty lanes. The rest has been dry! Perfect for your cx/winter trainer/tourer I reckon. Off road, so nice to be on the hoods and get the power with ease.

The power argument is a red herring - road caliper brakes are (mostly) more than good enough but it's not all about power.

Better modulation, consistent braking no matter what the weather, how cold your hands are, how tired you are, how laden the bike is.
The ability to run full internal hose routing, better integration, tight turns.
Allowing the wheel to be light and aero without having to have a braking surface as well.
(same with electronic gears to be honest; regular mechanical shifting is pretty much perfect but the actual gear shifting is a secondary function of how good they are for all the other reasons).

My Tripster ATR is specced with Tektro Lyra cable operated disc brakes and they are pretty damn astounding for a cable operated system, light, excellent modulation and i can do small rolling stoppies time and time again, no brake judder or fork/frame flutter thanks to the well thought out Kinesis frame design and whether i use one finger braking from the hoods or decide to grab a handful from the drops i can expect the same braking response time and time again.

Disc brakes just make sense but there's no point in trying to convert existing hydro systems to work from enlarged hoods/reservoirs as master cylinders, when the major manufacturers pull their finger out and start designing fully integrated systems from the calliper through to master cylinder then the UCI will have to acquiesce on their non approval stance.

Meh.

We shall see; I suspect that the market will be driven by what the big manufacturers think we should have, and by how much financial clout is brought to bear on the UCI rather than by anything else.

I've got 6 pairs of rim brake wheels to get through yet...

UCI will have to acquiesce on their non approval stance.

This is the UCI your talking about.

Those Hyrd things are bloody ugly. Can't see the point of them just like all cable actuated disc brakes.
The benefits of hydraulic disc brakes however are plain to see and perfect for year round commuting. Little maintenance which is essential when you arrive home in the dark and leave early the following morning, more reliable braking on wet descents approaching busy main roads, no wear on the rims and the cold hands won't have to work so hard during the freezing wet weather we get.
Riding over 100 miles a week, every week, all year what ever the weather I need these for my commute. Couple of years back I broke a weakened rim riding over a pot hole, in the dark when it was chucking it down. The rim walls had become thin from braking in the rain and grit and just split.
I've been waiting for this technology for years and now they exist I will tolerate my rim brakes for one more winter then make the move when the price is more reasonable and the tech is more established.
I'm sure a lot of the people who don't see the need in disk brakes don't use their bikes as a utilitarian means of transport more a pleasure device.

Hands up those who have actually ridden road bikes with disc brakes and would willingly give them up?

Keeping hands firmly down 😀
[img] [/img]

Don't need them. Ride my bike everyday in all weathers. Reflexes and sense are part of road braking. Off road disks are great for avoiding trees and small rabbits.

Mine are staying and more.
The day I can afford hydraulic/electric set ups I'll have them.
In fact if I had to have one I would prefer them on my road bike to the mountain bike.

Take it that, having formed such a strong opinion of them birdage, you've tried a few out over a decent period of time?

What didn't you like about them?

Of course not having to build in a braking surface will help with optimising aerodynamics at the rim. All of a sudden you're not constrained to having two surfaces that have to be paralell and about a quarter of an inch wide - without that you can contour the rim in that area to improve aerodynamics. Similarly you don't have to make that area thicker than it needs to be to build in a wear allowance and extra strength to resist braking forces in an already highly stressed part of the rim. Wasn't there a problem with carbon clinchers failing at the rim not so long ago?

Its a marginal gain, but that's all you're looking at on road bikes - there are no more step changes to come, unless you get radical.

I am going to put my penneth in here!
I have now put around 800 miles on to a C59-disc.
Frankly if you have'nt ridden one, you can't comment! They are chalk and cheese.
Generally people are right, road brakes are very good, but the control over power application in the dry is significantly better. You simply don't have the lag that exists on rim brakes, where you make contact, then pull a little harder to start to get some braking.
In the wet, there is no comparison, yes rim brakes will stop you, but no where near as efficiently, or with the same level of control as discs.
They are quiter than rim brakes, none of that nasty grinding noise whislt the brake cleans the rim, then dries it, then starts to do some braking.
In short i have so far found no down sides to them, and considering they are first generation road hydraulic they are excellent.
It is like electronic shifting, you don't need it , but when you have it you realize they do make a worthwhile difference.

SNIFF

Just bought my second CX bike to commute with. It has BB5's which are by no means perfect to set up but a country mile ahead of the rim brakes they replaced, which I'm sure will be a massive improvement when the winter comes.

The difference for me is like night and day, especially knowing I'm not grinding away my rims with winter salt and crap from the roads, I'd much rather change a disc than have a wheel rebuilt.

Think I'll be treating myself to a Hope V twin setup for Christmas.

I was far from convinced about road discs as per the fairly usual comments in this thread - no need, calipers work fine, etc.

Then I got my new CX frame which is disc only. I also use my cx bike with proper road tyres as a winter/crap weather trainer and actually as the new frame is fairly spangly, it's actually no slower than my 'proper' road bike.

The surprise for me was just how much better the control of braking is on the CX. With calipers there's plenty of power but I've often found that panic braking results in a short lockup followed by modulating it so slow down effectively. I've not locked up once on the disc'd CX.

In the wet, it's night and day though - I feel much better in control - largely down to the better feel/control and no delay in the brakes starting to work as they wipe water off the rim.

I've even been considering whether it'd be worth fitting a disc fork to my 'proper' road bike...