Disc Brake Road Bikes

[jimmycool]

I'd like to know too - I have doiscs on my CX bike, but the hubs are MTB specific hubs, thus no weight saving etc.

Yes, because effectively the brake is stopping the hub from turning and all of the riders weight/ momentum is trying to rotate the rim around the hub which is trying to stop rotating...

[Johan Bornman]

it's not about stopping power, it's about efficiency.

 

and judging by how road cycling is ALL about efficiency, i find it hard to believe road cycling is so resistant to disk brake technology.

 

cut cut cut cut

 

 

I don't understand what you mean by efficiency in this case. Perhaps you can explain or give an example pertaining to brakes.

[Johan Bornman]

JB, I remember a post from you a long time ago, where you explained the mechanical disadvantage of cable over the advantage of hydraulic that weighed most favourably toward disc brakes. How does this affect hydraulic rim brakes and would they be better than disc on a roadbike?

 

I can't remember the post. However, mechanical advantage in brakes has a very specific meaning and perhaps this is not what you intended in your question. The mechanical advantage of a brake is simply the amplification of force applied at the lever, over the force experienced at the caliper.

 

I don't think this is the question, but correct me if I'm wrong.

 

The disadvantage of a cable is simply friction and maintenance. Hydraulic systems always feel good whereas brake cables quickly deteriorates, especially the long rear one with openings everywhere.

 

The advantage of a hydraulic rim brake would simply be the convenience and feel of hydraulic, nothing else. In saying that I include the fact that a grippy, sticky cable doesn't allow you to modulate well and a hydraulic system would modulate better.

 

Since we already have enough mechanical advantage (as explained above) with cable brakes, we don't need more for actuating that same brake caliper with hydraulic. Enough is enough, so to speak.

[sadamhussein]

I don't understand what you mean by efficiency in this case. Perhaps you can explain or give an example pertaining to brakes.

 

by all accounts disc brakes are more efficient therefore it became the industry standard on pretty much anything with wheels.

 

just the advantage gained by using hydraulics over cables alone - no stretch, no loss of force applied, no cable snapping, no need for adjustment etc etc - should be enough of an argument for disc brakes .

 

having suffered rim brakes for the first 10 years of my cycling life, i cant say i can think of a single reason to argue in their favour.

[Bobbo_SA]

Replace the cable or bleed the brakes during a service, much of a muchness, although replacing cables seems to be easier in terms of the tools required and the potential mess.

 

Modulation (if that's the correct term) appears to me to be the only benefit, with traditional brakes you have a spring that is keeping the pads off the surface that you are working against all the time when braking, with hydraulic brakes the spring action is much lighter which in turn makes the lever action feel much lighter as well.

 

... no cable snapping...

 

I have seen a damaged hydraulic cable (it was damaged in a earlier incident with a rock / tree) "burst" when breaking pressure was applied further down the trail. This example was due to a single defined incident but I know I don't check the full length of my hoses for wear, I would expect the hoses to begin wearing around the headtube and BB areas on FS bikes, potentially making them weaker.

[Bobbo_SA]

Good article to read (possibly a repost): http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/

[Warren_G]

YES its a good idea

 

Reason:

When mtb's started getting disc brakes I was against them and had many an argument why I thought they were a *** idea.

I was wrong.

 

And that's why I think they are a good idea on road bikes, hoping i'm wrong again...

 

Have to agree with SwissVan here, it's simply the way forward...

[Wes84]

These where posted somewhere on the the forum a while back. Carbon rotors would make sense on a road bike if you'd want to go disk brake on your road bike right? In my opinion I think riders are constantly chasing performance, new tech and advantage. So if a disk brake in total can improve performance while reducing weight on a road bike it would be the choice over a rim brake. Then if you have a rim break that outperforms the disk brake as a total, that would be the choice wouldn't it?

Here is the website if you guys would like to go check it out (http://kettlecycles....le-brake-rotors). Credits to Kettle Cycles for that.

Edited July 9, 2013 by Der Meister

[MuddyMike]

I wonder how that front hub will hold up against the torsional forces exerted on it under heavy braking with a heavy rider on board?

These wheels are built on XTR hubs.

[Johan Bornman]

by all accounts disc brakes are more efficient therefore it became the industry standard on pretty much anything with wheels.

 

just the advantage gained by using hydraulics over cables alone - no stretch, no loss of force applied, no cable snapping, no need for adjustment etc etc - should be enough of an argument for disc brakes .

 

having suffered rim brakes for the first 10 years of my cycling life, i cant say i can think of a single reason to argue in their favour.

 

Hmmmm. Last time I looked all heavy trucks still have drum brakes.

 

You still haven't explained efficiency.

 

Remember, cables don't stretch and there is no significant loss of force applied.

 

No cables snapping - is that really an issue?

 

Adjustment - is that an issue?

 

I really think we're looking at disc brakes for all the wrong reasons. I have already acknowledged conditions where they do makes sense but I just see the same old fallacious arguments over and over again.

[Wes84]

Hmmmm. Last time I looked all heavy trucks still have drum brakes.

 

You still haven't explained efficiency.

 

Remember, cables don't stretch and there is no significant loss of force applied.

 

No cables snapping - is that really an issue?

 

Adjustment - is that an issue?

 

I really think we're looking at disc brakes for all the wrong reasons. I have already acknowledged conditions where they do makes sense but I just see the same old fallacious arguments over and over again.

 

With regards to all heavy trucks still having drum breaks, that is correct, a drum brake tends to have a lot more mileage on it, so they are built to "last" not having to change them every so often as trucks do hundreds of thousands of miles a year. How many times have you seen a truck come down a hill smoke bubbling out of those drum brakes? Not very efficient when it comes to continuous heavy breaking. Sand pits along side the road on downhills to stop runaway trucks? Bad brakes. Slap a pair of those drums brakes onto a super car like a Ferrari, they wouldn't be very efficient, in fact they would melt and probably catch fire. With regards to stopping power and heat a disk brake is very efficient. With regards to mileage and saving running costs a drum would be more efficient.

Edited July 9, 2013 by Der Meister

[Wes84]

With regards to all heavy trucks still having drum breaks, that is correct, a drum break tends to have a lot more mileage on it, so they are built to "last" not having to change them every so often as trucks do hundreds of thousands of miles a year. How many times have you seen a truck come down a hill smoke bubbling out of those drum brakes? Not very efficient when it comes to continuous heavy breaking. Sand pits along side the road on downhills to stop runaway trucks? Bad brakes. Slap a pair of those drums brakes onto a super car like a Ferrari, they wouldn't be very efficient, in fact they would melt and probably catch fire. With regards to stopping power and heat a disk brake is very efficient. With regards to mileage and saving running costs a drum would be more efficient.

 

Then again what are we trying to stop with the brakes we have?

[Johan Bornman]

With regards to all heavy trucks still having drum breaks, that is correct, a drum break tends to have a lot more mileage on it, so they are built to "last" not having to change them every so often as trucks do hundreds of thousands of miles a year. How many times have you seen a truck come down a hill smoke bubbling out of those drum brakes? Not very efficient when it comes to continuous heavy breaking. Sand pits along side the road on downhills to stop runaway trucks? Bad brakes. Slap a pair of those drums brakes onto a super car like a Ferrari, they wouldn't be very efficient, in fact they would melt and probably catch fire. With regards to stopping power and heat a disk brake is very efficient. With regards to mileage and saving running costs a drum would be more efficient.

 

The device on a vehicle that helps you stop is called a brake. Note, no "e" in brake, unless it is broken.

 

I think you need to do some research as to why trucks still have drum brakes. I'll give you a clue. Mileage has nothing to do with it.

 

Like Saddam, you use "efficient" too lightly. Stick to its meaning.

 

The smoke you see billowing out of truck brakes is the friction material burning. Incidentally, it is the same friction material used on disc brakes.

 

Bringing brake drums into the argument isn't helping this debate.

[Wes84]

The device on a vehicle that helps you stop is called a brake. Note, no "e" in brake, unless it is broken.

 

I think you need to do some research as to why trucks still have drum brakes. I'll give you a clue. Mileage has nothing to do with it.

 

Like Saddam, you use "efficient" too lightly. Stick to its meaning.

 

The smoke you see billowing out of truck brakes is the friction material burning. Incidentally, it is the same friction material used on disc brakes.

 

Bringing brake drums into the argument isn't helping this debate.

 

All true dude.

What i think in the end it comes down to is for what reason you want disk brakes on your road bike. If you fit disk brakes on your road bike and you can actively say that it increased your performance, helped to gain better times etc. and that is what you want out of them then it would make sense to have disk brakes on a road bike.

Fitting them because they look cool is another matter. But if you cant say that it made a noticeable difference in your performance/feel/time/reliability and you don't want them for looks, why would you fit them? It would be a waste.

[TopFuel]

JB, won't it help with power and modulation? Point being, yes I could lock up my V-brakes before, but it required much more user input than with my current disc brakes (XT), which only require a finger. So they may not increase power, but improve modulation throughout the lever's stroke?

[JA-Q001]

JB, won't it help with power and modulation? Point being, yes I could lock up my V-brakes before, but it required much more user input than with my current disc brakes (XT), which only require a finger. So they may not increase power, but improve modulation throughout the lever's stroke?

 

But, would you want to be able to lock up your brakes more easily? Do you want to be able to easily drag your rear wheel or go over your front? Ill say that they would have to increase the performance of road tires a lot before it is really needed to get disk brakes.