Why have disc brakes become so popular?

[[XAP]Bob]

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It’s what drives most incremental changes.

Because whilst discs are great, they aren’t (as has been done to death) the be all and end all of traction (which is actually tyre limited with any reasonably well up brake set).

[Brucey]

If there are so many people who claim (on this forum and in other places) that disc brakes are so wonderful, what was it that happened to suddenly make them available and/or popular?

I take your point that they still are by no means universal but they seem to be spreading to more and more bikes.

the manufacturers fulfilled a demand from MTBers for disc brakes (where they have some compelling advantages) and folk soon found that the same parts (more or less) worked OK on other types of bikes too. Without that experience and the development of near-commoditised parts, it is questionable whether disc brakes would have gained much traction in the wider bicycle marketplace. After all, previous attempts to sell them had basically failed.

It is a weird path to market though; usually some racing-inspired development is later shoehorned onto touring and commuting bikes, whereas with disc brakes they are making a reverse journey....

cheers

[Alan O]

I can't remember ever wearing out a steel rim

I don't think I can remember ever being able to stop with them - certainly never in the wet

[horizon]

the manufacturers fulfilled a demand from MTBers for disc brakes (where they have some compelling advantages) and folk soon found that the same parts (more or less) worked OK on other types of bikes too. Without that experience and the development of near-commoditised parts, it is questionable whether disc brakes would have gained much traction in the wider bicycle marketplace. After all, previous attempts to sell them had basically failed.

Nail on head?

But that does make me feel that disc brakes have more validity than those who believe it all to be a marketing ploy (even if it was dream come true for the marketing dept.).

[Alan O]

the manufacturers fulfilled a demand from MTBers for disc brakes (where they have some compelling advantages) and folk soon found that the same parts (more or less) worked OK on other types of bikes too. Without that experience and the development of near-commoditised parts, it is questionable whether disc brakes would have gained much traction in the wider bicycle marketplace. After all, previous attempts to sell them had basically failed.

Yep, I think that's pretty much it. There are serious advantages for MTBs, and the development of MTBs from their early-ish 90s steel versions (some of which were wonderful) to modern high-tech wonders has surely been the driving force. MTBing seems to me to have been a case where technological development aligned with a very successful market with perfect timing, and that's a recipe for rapid development.

As for disc brakes on road bikes, I'm still unsure. I love the fingertip response of the hydraulic discs on my MTB, and I've often wished I'd had that when controlling long downhills on my tourer with cantilevers when my fingers were starting to hurt. But I still love the simplicity of cantilevers, their ease of maintenance, and the beauty of being able to adjust their action however I want by simple changes to the yoke geometry (and I don't use those rigid yoke things, which seem to go completely against that).

Might as well mention caliper brakes while I'm here - I've never met a set that I've really liked.

[John1054]

I like the discs that I've got, but also liked the stopping power of the Suntour self energising callipers and the dual pivot callipers that were on the last two tandems.

[pwa]

I suppose once a technology gets a bit of momentum, as disc brakes have, it becomes easier for manufacturers to justify spending on R&D. So newer and, hopefully, better disc brakes will be on the way. But drum brakes are not going to develop as fast because spending on R&D is not as likely to be rewarded with a new product the market is ready for. A new improved drum brake would be harder to sell.

[JohnW]

Marketing and trying to give the upgrade cycle another whirl...

Spot on hamster - +1 to that.

[horizon]

I suppose once a technology gets a bit of momentum, as disc brakes have, it becomes easier for manufacturers to justify spending on R&D. So newer and, hopefully, better disc brakes will be on the way.

Yes, that seems to be it and MTBing just created that momentum and critical mass. The end result is a disc brake that is actually a lot better than previous discs and therefore more easily eats into other less obvious applications. And then presumably it's self-reinforcing.

[horizon]

Marketing and trying to give the upgrade cycle another whirl...

Spot on hamster - +1 to that.

Well, maybe not - it does seem as though something really did change even if later on it had marketing wind in its sails.

[Brucey]

they clearly still have not got it right though; just now I'm watching the TdF coverage and two chaps are off the front on a descent. One (Muhlberger) is riding discs and his brakes are making a terrible noise every time he brakes for a corner. The noise is so bad you can hear it over the sound of the camera motorbike and so loud the other chap (Alaphillipe) is visibly concerned by it...

[edit; unless it is the motorbike....?... ]

I would say that whilst the converse is not always true, if professional cycle mechanics cannot make something work properly in a race like the TdF then the technology is probably still a bit half-baked.

cheers

[JohnW]

I can't remember ever wearing out a steel rim

I don't think I can remember ever being able to stop with them - certainly never in the wet

I certainly go along with that - steel rims, especially for as long as the chrome lasted, didn't serve me well. As soon as alloy rims came into my life (late 50s, early 60s) my braking was transformed.

Using Mavic rims and carefully chosen brake-blocks I notice no disadvantage when compared with cycling companions who use disc brakes. Those who use discs believe that their rims last longer but they seem to have more queries and issues with their discs than I do with my various dual-pivot calliper rim-brakes.

I'm an exclusively a road- biker, but conversation and observation suggest that discs are a real boon to MTBers, and I can understand that.

[MikeF]

None of my bikes have disc brakes. The only advantage I can see for me would be that rims do not wear out. It's the front that wears, but installing a front disc brake means having a stiffer front fork and rougher ride. I'll settle for a smoother ride and occasional rim replacement. Disc brakes on the rear for normal riding seem pointless to me as a rear brake cannot provide much braking anyway, and a rim brake provides all that can be useful.

If you stick to the tarmac you can make a case. With the demands I have of my bikes, I don't miss rim brakes that clog up so badly the wheels won't rotate any more.

A Sunday spin

I don't always stick to roads, but then I don't normally choose to cycle routes I know to be in that state, although I've occasionally found myself in something like that for a short stretch. I would have thought the mudguards would have become clogged well before the brakes.

[Peter W]

We know that older steel rim brakes could be problematic (though NOT hopeless -or some of us wouldn't still be here) but that was not the point I was making.

Disc brakes use STEEL rotors but with special modern pad material which modulates, and works predictably in all conditions. For what reason wouldn't a steel rim, which is a very large diameter rotor, work with the same callipers and pads in the same manner?

We know that modern rim brakes pressing on alloy rims can work well, though not with the same modulation and light hand force as hydro discs, but I fail to see how a steel rim with hydro calliper and pads wouldn't outlast an alloy rim, especially in winter conditions, by a large margin.

My year plus old Roubaix road bike has hydro disc brakes and they have faultless and superb. Neither do they shriek or squeal, they just satisfyingly shhhs on application. Should they fail (piston trouble or salt corrosion problems) after say two years, I'd simply buy new ones, ready bled to just bolt on for way less price than having to buy two new wheels every couple of years for my older rim braked Roubaix. i.e. Two complete hydraulic brakes ready to bolt on and go (keeping same rotors) for around 160 pounds the pair, as against two complete new good wheels every two years for the older bike for ..... Ah well, how good do I want them to be? (Last pair Mavik Kysirium - if that's how it's spelt?)

[gnvqsos]

It is very hard to improve a bike and make new fangled bikes that are better.Manufacturers are developing newer devices(discbrakes) which may be no better overall.In the 1980s and 90s many people bought music they had aleady paid for renouncing vinyl for CD format records.Ironically the conosewer now plays his vinal on a £2000 record player,even though the sound quaklity is poor.