Disadvantages of disc brakes?

[Nigeyy]

To be fair, I wasn't clear. I meant to say that the inclusion of a disc will cause the spokes to be further to the inside of the hub than they would be otherwise if no disc was there. That will -all things being equal -make for a weaker wheel. Almost all rear wheels and front disc wheels are dished to some extent.

Having said that, I believe a wheel well built with the appropriate number of spokes, good quality rim, hubs, etc will negate that. Think of it this way: if discs caused weak wheels, the mtb community would be in big trouble!

I personally think this "disadvantage" is specious (but the op asked for disadvantages!).

 

[SatNavSaysStraightOn]

I've toured on both and I prefer my rim brakes over the disc brakes. But I am not comparing like with like. Simply what I have toured on.

I did a 800 mile tour on my mountain bike with hydraulic disc brakes. They were whatever came as standard on the Scott Scale 40 (2010 model), not exactly a bike designed to be tourer on (I also used it on mtb trails as well, complete with pannier rack!).

I've done a 8,700 mile tour on my off-road touring bike (designed for remote areas of the world) which has Rigida Andra 30 26" (559) MTB CSS Rim's combined with Swissstop Blue Brake Pads for Deore / LX / XT / XTR Brakes - for Ceramic & Carbide CSS Rims, neither the rims nor the pads are cheap). (sorry direct copy from the invoice made life easier for me)

Why - well part way into 2 week tour (thankfully in Denmark, somwhere with plenty of bikes, bike shops and very helpful cyclists) my disc brakes seized up completely. Denmark is not exactly mountainous... so no major decents or anything like that. The brake dust had built up so much (somehow) that it had effectively applied my brakes permanately on for me and the front wheel would no longer rotate. Perhaps I should have known this was an issue? maybe. But I have had no issues whatsoever with my rim brakes in 8,700miles on tour and more off-tour. I have not had to do anything except change the pads once and we have covered some long descents fully laden at speed (one in particular that comes to mind was upto 60kph fully laden for 2.5km and another which had a 700m vertical descent again fully laden in winter conditions (kit is generally heavier in winter)). We have never had to deal with brakes overheating, rubbing or squealing, only wearing out after 4,500 miles for the first set, the second set will last much longer and are already at 4,200 miles and don't even look worn.

But like I said, I'm not comparing like with like and both of those setups would stop on a six pence. Would I have disc brakes for a bike staying in the UK or even western Europe/USA or somewhere that is not that remote? Yes, happily, but not for anywhere else in the world. Its the same reason I have a steel tourer - ability to repair in remote parts.

So it comes down to the age old issue - personal preference and what the bike is going to be used for.

 

[Ticktockmy]

I find it hard to make comparisons between disk or rim brakes, I have bikes with both types, and have toured with both types and never had problems, I have in the last few years got a preference for the disk brake system mine are Hope X2, and have had no problems at all, I change to sintered pads during the winter month, and back to standard pads once the weather get dryer. With rim pads, I have found that different makes have different braking performance, some seem to wear the rims more so than others. I must say that I have never known anyone who has had their front wheel pull out of the front forks due to excessive braking using disk brakes. I think one has to think about what use the bike will be used for then purchase a bike or bike parts suitable for that use.

 

[Crankarm]

Well I've been commuting on my Kona MTB which has cheap Hayes disc brakes which have been pretty good apart from occasional rubbing and squealing which I have to say has at times driven me mental. But on balance I prefer them to traditonal rim brakes as stopping power is superieur on a loaded bike and brake dust and gloop on the wheels is far less so less time spent cleaning the bike which is a major advantage.

 

[MontyVeda]

what's all this 'stopping power'?

Both rim brakes and disk brakes, when set up correctly are more than capable of locking the wheel in both wet and dry conditions (unless you have a vintage bike with old chrome plated steel rims)... the most efficient point of braking is just before the wheel locks.

So what's all this 'stopping power'?

 

[Bodhbh]

Suppose with hydrolics if the cable gets ripped or something, you're pretty buggered. But they are just so damn maintenence free. I started touring on a converted MTB 5-6 years ago, so I've had deore hydrolics since the git-go and apart from changing the pads, they've needed nothing doing to them, nada. I use the bike for the commute and off-roading too so they get it all. I bled them, but they didn't need it as they were the same after. Now they're the only remaining thing left from the orginal bike, everything else including the frame is replaced.

If I was building a tourer up from scratch I would probably go for cable discs, especially if I was planning on going anywhere remote, but fairly happy to leave the hydrolics on till they go kaput.

My mate who I tour with has a Thorn Sherpa and it gives me a good benchmark to see how my homebrewed thing stands against a traditional tourer, and the brakes on either are pretty much equal underload - until it gets wet or you ride thru alot of crap then the discs shine. Which is I suppose stating the bleeding (excuse the pun) obvious as that's why they're on MTBs.

 

[andrew_s]

I must say that I have never known anyone who has had their front wheel pull out of the front forks due to excessive braking using disk brakes.

I have - a companion on a camping tour round the alps.
Fortunately it was at low speed in the most convenient location possible (just pulling up at Briancon campsite), and the only casualty was a pair of written off forks. A short while earlier and it would have been half way down the Galibier, and a great deal more serious.
The problem was no lawyer lips and the allen key skewer in a SON dynohub.

what's all this 'stopping power'?
Both rim brakes and disk brakes, when set up correctly are more than capable of locking the wheel in both wet and dry conditions (unless you have a vintage bike with old chrome plated steel rims)

a) You get your stopping or speed control done with less hand pressure. This is significant with heavy bikes, big hills, wet conditions or if you are somewhat less than Charles Atlas. Also, if you aren't squeezing so hard you have better control.
b) I'd have to disagree about rim brakes working well in wet conditions. There's the delay whilst the brake wipes the water off the rim, which you can allow for normally, but not when it's something unexpected such as a car pulling out in front of you, and if it's properly wet rather than merely a bit damp the rims get wet again as fast as the brake wipes the water off and you never get decent braking.

 

[MontyVeda]

...
a) You get your stopping or speed control done with less hand pressure. This is significant with heavy bikes, big hills, wet conditions or if you are somewhat less than Charles Atlas. Also, if you aren't squeezing so hard you have better control.

what a crock of crap

b) I'd have to disagree about rim brakes working well in wet conditions. There's the delay whilst the brake wipes the water off the rim, which you can allow for normally, but not when it's something unexpected such as a car pulling out in front of you, and if it's properly wet rather than merely a bit damp the rims get wet again as fast as the brake wipes the water off and you never get decent braking.

more crap

...but if it helps you justify your purchase

 

[Red Light]

Hydraulic brakes aren't available for drop handlebars.

Yes they are and I have some. Hope V-Twin hydraulic adapter for drop bar levers. Magura used to do an HS66 hydraulic drop bar lever but it wasn't a brifter and therefore limited appeal. The V-Twin will adapt any drop bar lever for hydraulic brakes though.

 

[Davidc]

In my thinking the big advantage of discs is keeping the braking away from the rims. The big disadvantages are complication and flimsiness. Put together this comes to a don't care balance. Unless steel rims reappear, then it's discs all the way.

I have not yet replaced a wheel because the brakes have worn the rim away. I have replaced one because it was worn out (as in small fatigue cracks visible at the bike's annual service) That wheel would otherwise have been replaced soon afterwards because of rim wear from braking. On more expensive rims than I use, which are often softer I can see there's a problem. Rims normally get replaced because I've bent them.

I have ridden a MTB with discs. They are good brakes. However. With decent pads fitted (not the manufacturers original ones) I get as much braking as can be used on both my tourer (cantilevers) and my town MTB (V or linear pull). Both front brakes can start to lift my 13 1/2 stone + bike if I have to do an emergency stop.

I am not superman, but find that on both bikes braking only takes a sensible amount of effort. I can fully apply the brakes with no difficulty..

I think disc brakes are a better solution to brake design than rim brakes, but not enough to make changing an existing bike to them a sensible option. One day I may but a bike that has the m fitted. I will find out how to service and maintain them, and happily use them.

I really don't understand the fuss or strong feelings on this one. Hydraulics seem a good idea, but why can't we have that with cantilever or caliper rim brakes if it's such an improvement?

 

[Davidc]

Yes they are and I have some. Hope V-Twin hydraulic adapter for drop bar levers. Magura used to do an HS66 hydraulic drop bar lever but it wasn't a brifter and therefore limited appeal. The V-Twin will adapt any drop bar lever for hydraulic brakes though.

Including STIs? And as above, can hydraulic cantilevers, calipers or linear pull be bought?

 

[Red Light]

Hydraulics seem a good idea, but why can't we have that with cantilever or caliper rim brakes if it's such an improvement?

Cough... Magura!

Magura hydraulic rim brakes are far superior to cable rim brakes IMO - almost as good as discs.

 

[Davidc]

I'll have a look, but I can get as much braking as I can use with cables already so there'd need to be a big improvement in control and feel to justify any change.

Edit: Had a look, will look again when the price comes down by 90%.

 

[Red Light]

Including STIs? And as above, can hydraulic cantilevers, calipers or linear pull be bought?

Yes, I have a V-Twin on STI set up on one of my road bikes. And I have Magura hydraulic cantilever brakes on the tandems and my hardtail mountain bike. What I don't have is the Magura hydraulic caliper brakes although you can get them on e-bay still (Magura HS11 or HS66 from memory). They have a dedicated drop bar lever though so you need to go to bar-end or down-tube shifters with them.

 

[Red Light]

I'll have a look, but I can get as much braking as I can use with cables already so there'd need to be a big improvement in control and feel to justify any change.

There is, trust me. Its not the quantity of the braking, its the quality - steady, progressive and very consistent and predictable giving much greater confidence you can stop where and when you need to.