LesterOfPuppets

So it's a Scandinavian thing?

Ty0604

I have no idea the origin of the word or anything.

MikeOK

Some road bikes do come with discs. The main reason why you dont see more is that you don't need the braking power of discs on a road bike. I rode my old Trek over 40,000 miles and didn't have to replace the pads one time. On my mountain bike with discs I had to replace them at least once a season. Another disadvantage of discs on a road bike is the added weight. Roadies can get pretty anal about every gram of weight.

FBinNY 

Fujiyari? Isn't that the dormant volcano west of Tokyo?

Cyclist0108

Yeah, but at least that enables you to make a good beer.

PS: Hope you are healing well!

Ty0604

haha Pebs likes IPAs. I'm more of a cider person. Am doing much better, thank you! Heading out next week to begin an ~800 mile tour of Yellowstone & Grand Teton. Oddly enough I feel in better shape now than I did before the accident.

Here's a story from late last year regarding disc brakes in road racing for anyone who wants to read...Disc brakes to return to road racing in 2017 | Cyclingnews.com

coominya

Yes, once they are the "fashion", everyone will be lining up.

DomaneS5

Jeeez. I had to replace the rear brake pads on my Trek 1.1 after 1.5K, but I do ride a lot of hills. Must be the entry level brakes.

Garilia

OP, please explain why you think road bikes do not have disc brakes.

DomaneS5

Funny how I could have had disc brakes on my latest road bike for an extra $500.

fietsbob

We shall see, You may buy Road bikes limited tire clearance, or Cross, able to fit bigger tires, Now.

Both with Disc Brakes, But...

the Pro' s in the TdF, etc. may stay with rim brakes due to easier quick spare wheel support on the road,
During the races when they puncture... and they do have dozens of spare wheels..

wphamilton

Four years ago https://www.bikeforums.net/bicycle-me...ike-discs.html we figured that marketing was the main force pushing road bike disc brakes.

Weight, mechanical complexity, cost, increased size/drag, and the stronger rear triangle needed are the downside. Better modulation at the handles is the advantage. Not wearing out rims is another.

At one time, I figured that discs would allow you to develop anti-lock on back, and anti-pitch-over on the front. But outside the box, you could also do that with rim brakes and a solenoid or motor pulling the cable if you really wanted to. Nobody has gone that route yet, so it's probably not as useful as I had imagined.

Maelochs

I think the forces involved are too small and the dividing line too narrow.

The fine control needed to manage forces across so small a contact patch with braking times already being so short .... the gear would be more on the line of laproscopic robot surgery than automotive. The costs would be commensurate. And the gains would be minimal.

wphamilton

I don't follow the reasoning, but you're probably right about minimal gains which makes it moot. Sliding on the back isn't very urgent an issue, and the front won't slide (on straight braking on the road), which mostly rules out anti-lock anyway. Maybe wet surfaces, ice? I'm not certain if it would help, or not help.

leob1

You sound like Sheldon Brown more and more. When v-brakes started becoming popular because they where 'better' than cantis, his position was well set up cantis are better than poorly set up v-brakes, and visa-versa.
The same hold true for caliper vs. disc for road bikes now.

Maelochs

Reasoning. This is BF, why would i use "reasoning"?

I just figure that a car has a contact patch of maybe 100 square inches, and a bike, about two. And a bike's braking event is really quick. A bike ABS system would need to be super-sensitive and super-quick.

It would have to cycle really quickly or it wouldn't really "cycle." It would just release the brakes once and squeeze again (judging by the pulse through the pedal on my car's ABS.)

Also, the distance it would need to move such a very light brake arm ... literally a fraction of a millimeter. That kind of precision reminded me of robot surgery.

I could have said "NASA-like precision" or something.

The forces involved with a car, where a single wheel's braking system probably weighs more than my bike, versus the tiny pads on my bike ....

As soon as Shimano figures it out, we will see it in the TdF, and then we all will want it .... i guess.

prathmann

A very simple mechanical anti-lock braking system is illustrated in the book "Bicycling Science." The rear caliper brake is mounted on a post so it can slide forward when actuated and a spring returns it to the normal position when released. The front brake cable is mounted so it's pulled by the sliding action of the rear brake rather than being controlled directly by the rider. This provides very strong front braking just until the rear wheel begins to skid a bit due to the weight shift thereby relaxing the pull of the rim on the rear brake. The article in the book indicates that the system worked very well in testing until eventually they broke the front fork due to fatigue from all the hard stops. But it did provide consistent minimum distance stops with no danger of pitch-over regardless of how hard the rider applied the brake lever.

Obviously there are some issues with this system. No ability to independently operate the front or rear brakes depending on surface conditions and also a single point of failure - if the rear brake cable snaps you lose both brakes. But it could be supplemented with the addition of a third independent brake with its own cable.

wphamilton

Fascinating, combining the two ideas into one mechanism and the operating principle makes perfect sense. Probably for another thread, lest I hijack this one, but you've given me something to mull over. Thanks.

ps, I was envisioning leaving the front cable in place, so you could just pull more on the lever if the electronic mech failed.

rydabent

The OP needs to read up on the latest offering from almost all bike mfg, and he will see that indeed disc brakes are most certainly available on road bikes. Even Campy has released a line of disc brakes for road bikes. The single biggest reason is the fact that with disc brakes, rims are not worn out and scabbed up, and the rims can be made stronger and more aero if they dont have a brake surface.

LesterOfPuppets

V-Brakes aren't even significantly "better" than cantis. They are almost infinitely easier to set up for a beginner factory or bike shop worker, however.

FBinNY 

I knew Sheldon well, and I guess I should be flattered. In fact, he and I probably agreed more than we disagreed, and the canti vs. "V" brake question was one where we didn't agree.

But this is very different. Changing from classic cantis to the newer design didn't introduce any new problems, so there was nothing to offset any benefit.

OTOH - discs introduce all manner of issues, including the need to redesign wheel mounting systems, stiffen the fork, along with increased weight and cost. That's not to say there aren't benefits, especially for people wanting CF rims.

IMO - on balance - disc brakes don't make sense for racing and most sport riding, though they may make sense for other "road" bike applications such as commuting or touring.

I don't have a problem with disc brakes for road bikes, but do have a problem with the notion that they are somehow "better" in an absolute sense. IMO - it's never a question of better or worse, as much is it's a question of better or worse for a specific purpose.

Unfortunately, there are various bike industry factors, mostly economic, driving the effort to create the illusion that disc brakes are the future and convince folks that they are somewhat disadvantaged by not replacing their working bike with the "new and improved" products.

LesterOfPuppets

In addition to the easier setup for assemblers, V-brakes also made manufacturers' lives easier by eliminating two cable stops per bike. Total win-win for bike makers.

Seattle Forrest

Garilia

i don't speak to the superiority of one braking technology over another, I don't think about it that much. This post has generated some great discussion though. I will simply say that some people seem to use "road" bike when they really mean "racing" bike. In my mind, Road Bike is a broad category that includes racing/sport, touring, commuting, cyclocross, TT, triathlon, single speed/fixie...

Where do flat bar road bikes fit in, or are they hybrids? What about a drop bar hybrid?

This is why I try not to think too deeply about these things.

rgconner

In the IT World, we call "better" a "Non-functional requirement" as it is not measurable unless you know the actual functional requirements behind it. Like:

1. Little to no stopping in the rain is very important.
2. I do long fast descents where I am riding the brakes constantly.
3. I am putting it on a Tandem bike and require the extra braking power.
4. I want the lightest bike possible.
5. I want the bike to be bullet proof and not have to adjust things all the time.

There are of course more functional requirements than that, but they are all well defined and a disc vrs rim braking system could be evaluated against them to decide which is better.