davebean

There are a lot of road bikes coming out this year with disc brakes. I think this is the first year they are coming out en mass. Are the manufacturer's making wider frames to fit the discs or re-designing something else????

Reason I ask is because I want to build out a disc road bike next year and a friend has these parts for sale -

Triple shifters, 10 speed. ST-4600
105 triple front Crankset 50/39/30 and 175mm arms FC-5703
105 triple front derailleur FC-5603
Tiagra long cage 10 speed rear derailleur FD-4600
Shimano 105 11-25t cassette CS-5700

If I buy them now, can I put them on disc equipped road bikes or is there some sort of limitations on the drivetrains for disc brake road bikes?

Thanks in advance.

rydabent

I am a great booster of disc brakes. To me it is just plain stupid to wear out expensive rims using them for a brake surface now that we have disc brakes. Also rims without a brake surface can be made stronger and more aero.

I predict that discs will pretty much be standard in a few years.

HillRider

This has produced long and very heated threads here lately. A search should provide a lot of entertaining reading.

fietsbob

for consumers there is a market *, even if the Pros never use them , or do only if their paycheck from a
company paying for a high profile test demands it.

Something they can use in promoting sales to the top spenders in the Bike sales campaigns

* already is as a gravel-grinder thing and cross bike drop bar commuter .

Road bike to me only suggests the clearance for the wider tires is Eliminated

So you can already get a $4K bike with disc brakes you can ride on the road..

break out the TITANIUM credit card ..

cafzali

First, realize that discs are a reaction to the fact that in many ways, the high end market has been pushed as high as it can go from a materials and weight standpoint. So, wanting to try and justify a replacement cycle from some, discs became "the bomb." They're certainly fine as tech goes, but the fact is most people don't race, most don't have carbon wheels and most go 2-3 years before they wear out the pads on their brakes.

Given that, the gains that discs would generate for many people are marginal, at best. Contrast that with a CF frame and even if you're not racing, you can appreciate the fact that the material dampens road vibration and makes for a more comfortable ride.

mtbikerinpa

I'll just be glad to not have wet brake pad issues...

FBinNY 

Disc brake road bikes represent a triumph of marketing over practicality. Basically they are a solution to a problem that doesn't exist, and replace a simple, inexpensive brake with a costlier, heavier one. The industry has become like a shark, which must keep moving in order to stay alive. Facing near zero growth in customer base, it must find ways for existing customers to replace perfectly good bikes with newer "better" ones.

The issue of rim wear is a red herring. The number of people wearing out rims on road bikes is about as close to zero as it's possible to get. Even in heavy urban use, it can take 25,000 miles to wear through a road rim, and on open road riding where brakes are used less it's more like 50,000 or more miles. So typical rim life exceeds the lifetime mileage of most bikes, and the simple fact is that the vast bulk of rims or wheels that are replaced are because of other reasons such as spoke breakage, crashes, etc.

In any case, even if rim brake track wear were an issue, a simple, efficient remedy is to increase brake track wall thickness. Doubling the brake track thickness would add maybe 10-20% to rim weight. This would be a smaller increase in weight than a disc brake system would add.

As for those who make a wear cost issue, a simple comparison of what's actually spent for brake wear costs rims/shoes vs. discs and pads, shows that rim brake users are spending far less.

So the "advantages" of disc brakes on a road bike, are more weight, higher cost, both up front and over the life, and more finicky maintenance. Any knowledgeable person has to wonder who's gaining and what's driving the road disc brake marketing effort.

There is one segment of the market which may benefit from disc brakes, and that's all weather urban commuters. The need for fast hard stopping in the rain, on busy roads where there's always the element of surprise, may make the quicker response of disc brakes advantageous. But even here any improvement will be marginal, because braking is still limited by tire traction, and rim brakes are already up against this wall.

fietsbob

+ of note: the Louisville Cyclocross Worlds , the UCI Pros,

the first rider with disc brakes on their bike came in 10th.

and had braking problems with them in earlier heats ..

cafzali

I don't know that that's ever been stated as well on this board as this contribution. It's all about marketing with neglible benefits for 99.9 percent of people. Mtbiker, you may ride in the rain and they have advantages there, but most roadies don't. So unless you ride in moisture and muck, you're paying a penalty for a system that you don't need.

Even "weight weenies" get some benefit from their expenditure, even if you can't really justify it from a value standpoint.

noglider 

FBinNY, thank you. I've been trying to picture myself going to disc brakes, and I just can't see it. Now I know why.

Wearing my rims out? I've been riding a fair bit for the last 39 years, and it hasn't happened to me yet.

FBinNY 

On the road I ride tubulars, using rims with a TOTAL wall thickness thinner than the wear allowance of most clincher rims. I have yet to come near to wearing one of these out. Ever.

OTOH, my commuter which sees tons of stop and go urban riding in all weather, shoes serious rim wear after 25,000 miles of this. I figure there's maybe only one season left. But compare that to the typical disc life and you'll see that even in this hard use, rims outlast discs, possibly by enough to finance wheel replacement with the savings.

Every once in a while, I think about disc brakes if/when I build a new commuter. Not because of safety or cost, but because it my allow less adjustment of riding in the rain.

elcruxio

I hate it when people say this. Every single innovation in bicycling has been a solution to a problem that did not exist. To name a few, Carbon, aero, better steel grades, aluminum, scandium, aheadset, BB30, outboard bearings, brifters, derailers, gears, etc. But that is not how progress or innovation works. You can make things better even when you don't have a specific problem.

Depends on who you are, how you ride and do you take your ride out in the rain. With my old pads I could have worn my rims down in under 5000 miles easily. I switched to kool stops with the cleaner lip and the issue got better but my CXP33 are still starting to show signs of wear. This is probably due to riding in the rain and gravel roads, sometimes at the same time. Discs don't have this problem and the stopping power remains consistent.

Yeah, because this is what we want. More rotating weight. No actually one of the ideas behing racing discs is the removal of weight from the rim even though more weight is added to the hub area. In the hub area weight doesn't matter that much. But really the disc allows for more aerodynamic rim designs and when disc calipers/discs develop we will most likely see pretty same aerodynamic numbers than with rim brakes. The current difference isn't even that big.

Didn't even know this was an issue.

The actual advantages are:
Better braking power. Well, you don't really need more power but there you have it.
Much better modulation. Many retro grouches will say the modulation of good calipers is quite sufficient but the modulation of a good disc is just SO MUCH BETTER. They are practically two different worlds. I mean good brake feel and the confidence that follows is awesome.
No rim wear. As stated above this is more of a problem for some and not so much for others. But in the age of carbon rims I can suspect eliminating rim wear from a 1000$ zipp is not to be frowned upon.
Easier maintenance. Seriously, have you ever fiddled with discs/calipers/other brake systems. I've gone through practically every system there is and the best by far is hydro disc, second is mechanical disc and far far behind are the rim thingys. I absolutely detest doing anything with rim brakes as they are more often than not just horrible to adjust and the rim needs to be within 1mm true to get any good power out of them.

A few neutrals.
Heat. Rims get heat. Discs get heat. there is no clear winner here yet since to get good heat resistance with rims you need to go alloy or really expensive carbon. With discs you need a bigger disc. No biggie.
China carbon in this situation is unfortunately not an option (hence discs are awesome for those who want cheaper carbon rims from china).
Price. The RED hydros are expensive. Avid BB7's are not. End of story.

Negatives are of course
Weight. ATM the weight is still an issue but some carbon manufacturers are already developing lighter more aerodynamic rims which will offset this problem.
Aerodynamics. The difference is not great and if we're not talking about a TT bike it should not be a biggie. A few seconds over 40km.


It's not about the power. It's about brake feel, consistency, modulation, security, trust and other issues.
An anecdote. I had an old Volvo 240 GLE which had pretty bad brakes. You needed to really push on the pedal to lock the wheels and that was the limit of braking with that car. Now adjusting your braking between locking and wheels spinning is actually not easy when you are excerting a lot of force with your leg. It can be learned, as I did, but it would have been nicer to use a brake which you can lock with just firmly pressing your foot down. It would have made modulating the brake power so much easier as is the case with my dad's car currently. This same effect is even more prevalent with bicycles as too much brake means OTB or just front wheel slip.

FBinNY 

I acknowledged that folks with lots of wet riding might benefit from disc brakes, so no disagreement there. The rest isn't all that relevant, since the differences are marginal at best, and not worth the need for stronger stiffer forks or other drawbacks disc brake impose.

While people keep talking about modulation, this too is a red herring,because caliper brake have excellent modulation and it was an issue with good brakes until disc proponents brought it up. OTOH based on observation, disc brake modulation may not be as great as they make it sound, since I routinely see disc riders accidentally locking rear wheels in less than ideal road conditions such as sand, gravel, or wet. Of course people can learn to modulate better, but I wonder if there's such a thing as too much brake, and if it could create new hazards in emergency events.

Personally, I have no objection to disc brakes, people should have choices and buy what they want. But we're seeing a force feeding, and unless users resist, we'll see a total shift to disc, with no quality rim brakes offered at the upper end.

Those who want to feed the shark are free to do so, the industry needs them. As for myself, I don't feed sharks.

elcruxio

Modulation is not a red herring. It's reality. Rim brakes don't give the same modulation or power as discs do. They just don't since there is only so much you can do with rubber and aluminum, not to mention carbon.
Also, rear tire slipping is technique issue. Even I get it from time to time but I take it just as a good thing. It means I'm actually braking hard enough and I use that to modulate my braking. It's like braking with a car with no ABS but with two components instead of one.

Furthermore I would not panic overly much about "sharks" as you call them. Bike companies are always going to sell, that's how they roll and that is precisely how we get cool new technology. There is still alot to come, don't you worry.
A few bikes with discs which are in comfort bike category does not disc overpower make. And even when UCI allows discs for road racing they are still not going to be the norm as especially in the road community there is always going to be weight weenies. But they are going to be an option which is awesome. Or maybe discs will be the norm someday but that will take years and years still. What I, and many other riders want is options.

I personally see discs as sustainable development. As much as I love building wheels I am forced to push my dream of carbon wheels forward until the disc tech is matured a bit. I ride every weather and even tour on my racing CX/roadbike so wearing down rims which cost 200$ a pop and brake so badly to make you cry is just not an option.

Just imagine how cool a bike be if it had all the new fangled awesomness of today's innovation
Discs,
Dropper post (road specific of course)
Thru axles
deep section carbon rims with aero spokes
tubeless tires
High end reynolds or carbon frame. (personally I would love a Cervelo S3 with thru axles and discs but that beauty will still be a few years in the coming but for touring there is no material like steel)

fietsbob

++ if the road surface is sketchy and Wet the contact patch of a 115psi 23mm wide tire
will be the size of a nickel ..

then you would be better served bu a wider tire , anyhow ..

and the CX/Commuters are already selling well at the present.

you can already buy a full Carbon - Disc cross frame , just build a really expensive set of wheels

with all those features and narrow tires on it , if that is what floats your boat.

The Hansenator

What I like about disc brakes is I don't get that horrible grinding noise when I ride through a puddle. Besides that, I've never had problems with the other kinds of brakes I've used.

cafzali

Those innovations solved a want, not a problem. And discs may end up becoming a want too, but right now there's no clear indication of that. You're adding weight and complexity for no reason. Add to that, the vast majority of bikes out there don't even get ridden regularly because most aren't bought by hardcore cyclists. Of the regular riders, even fewer ride in wet conditions. So basically your market for discs are hard core cyclists who are concerned about braking in wet conditions. That's not enough to justify it as a need and I just don't see it becoming "sexy" enough to become a must have "want."

Weight and a smoother ride, people can understand. So that's why carbon took off even among non-racers. But things like braking modulation, etc. most won't. So you'll likely see that relegated to a niche part of the high-end bike market. All I'm saying is people who are predicting it will become standard are a bit premature. Biking doesn't have a federal agency that mandates safety improvements, which is what made antilock brakes, airbags and other things take off in cars. The closest biking has is the CPSC, which only gets involved in issues where a defect can be proven.

noglider 

I can see a reasonable compromise of viewpoints between FBinNY's and elcruxio's. If discs become the predominant type of brakes after a while, rims might become lighter, as might disc brake calipers. Calipers might become cheaper, relatively. Rim wear really is a non problem, but once disc brakes are more common, we probably won't long for rim brakes any more.

I remember in 1985, people started buying color monitors and adapters for their computers. I didn't see the point. I was perfectly happy with my monochrome computers. It seemed like a waste. Clearly, my opinion didn't count much.

Rooster09

Alright, we're almost 20 posts into this thread, and I'm going to do the unthinkable: answer the OP's question.

Yes, those components will work with disc brakes. Generally the only component change is a wider rear hub (135mm vs 130mm).

I just built a disc road bike using a 105 group with no trouble. As far as this debate about them being a good idea or not, who cares for a recreational cyclist? Use what feel better to you. I went disc because I'm coming from mountain biking and am used to the feel and maintenance for discs and weight really doesn't matter to me much. To each his own.

FBinNY 

I don't see it as a question of compromise, more like apples and oranges. It's very possible that Elcruxio and I agree more than we disagree.

While I don't recognize the so-called benefits of disc brakes for road bikes, I'm referring to sport road/race bikes. We've had sisc brakes on hybrid bikes & touring for quite a while, and I don't think there's anything to debate there, and anyway there's plenty of choice. My anti-disc post relates to the industry's effort to push disc brakes into the high end road category, where they don't make sense.

One problem with the bike world, is that the high end products are designed and marketed for either road racing or serious off road use. Neither category is well suited to the needs of most of the market, and there's a tendency for new stuff to squeeze out quality older stuff. Anyone who wants to ride 9s road or 8s mtn know what I'm talking about.

I'd be much happier if the industry supported multiple categories better. Imagine if the auto world decided that all top quality cars would only be Formula race cars or 4x4s made for serious off road use. The auto industry does a decent job offering a quality/price spectrum in multiple categories, and supports their vehicles for many years. The bike industry is driven by creating a need to upgrade.

john.b

Not sure what that has to do with disc brakes on road bikes, but Sven Nys won the BPost Bank Trophy series in Belgium this year with hydraulic disc brakes. :shrug:

fietsbob

Nys can beat people riding just about anything his sponsors place him on .

read Trek is making him their New Lance ..

HillRider

You had me agreeing with many of your points right up until I read this. Rim brakes are difficult to adjust?? Road calipers are about as simple and straight forward as anything I've ever dealt with and V-brakes aren't far behind. Cantis take a bit more finesse but none of these could in any way be considered difficult or tricky.

noglider 

FBinNY, you often make me think. Your viewpoints are, to me, nuanced and interesting. I appreciate that very much. You're right that the need to upgrade is too big a force. I'm familiar with this. I'm not convinced it doesn't exist in the car market. But yes, too much is made to ideally suit a top notch racer when most bike customers ride for fun, not top competition. Guys like you and me are, to the market, not worth the trouble.

Retro Grouch 

One other MAJOR point has been completely left out - the coolness factor. Disc brakes have it. I don't know how to measure how much that counts in the purchase decision but, if you think that it's zero, you're wrong for sure.