Disadvantages of disc brakes?

[Red Light]

There are obvious advantages in terms of braking quality. The principal disadvantages on a tourer are that they are more vulnerable, and that they require a stiffer and thus less comfortable fork. My personal preference on a loaded tourer is for Magura hydraulic rim brakes. But if budget is a concern, I think nothing beats a pair of Deore v brakes, particularly if used with Koolstop Salmon pads.
Willem

I would say from my experience that rims are more vulnerable (dings and dents) than discs and when they are dinged they can compromise the braking quite a lot. With a disc its easy to take an adjustable spanner to it and bend it back straight but they are pretty tough and hard to damage. Have had to rebuild wheels to replace damaged rims on tour a few times but never discs.

 

[Flying Dodo]

I don't have a disc equipped bike & I'm neither for nor against discs, but surely a disc equipped bike stresses the wheels more than a rim braked bike?

Discs must have the same effect as the rear wheels drive "hub twist" in the opposite direction & at a much much greater force (can you accelerate in the same distance you can stop?) so I expect spokes have to be stronger (& wheels relatively heavier), the front forks beefier as well as the weight of calipers, etc.

Rim brakes don't twist the hub in the rim, the braking forces on a rim braked wheel are similar to just putting more weight on the bike, but no twisting forces.

I can understand the advantages on a MTB where rims are subjected to more dirt & can be ground down quickly, & how nice it must be to be able to run bucked wheels without issue.

What I don't get is where any of this is useful on a road bike, where over & over again simplicity has proven to be the best bet for trouble free cheap cycling. So MTB yes, road bike no.

But I'm happy to have my opinion changed

I've been test riding a number of disc equipped road bikes recently, to replace my old commuter bike. Although most of them are nominally cyclocross bikes, they're all pretty light. The main reason I'm looking at discs is that having a rural commute, I don't want another winter of snow jamming up the brakes, plus I know the discs will stop me quicker in the wet.

 

[Blue Hills]

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.

I'd agree about Magura hydraulic rim brakes. I have a set of pretty old HS11s on my Cannondale - what you might best describe as a flat-bar fast city bike.
I've never touched them at all in years and years apart from replacing brake blocks. Blocks are decent value, cheaper than many more "normal blocks" in fact, and are an absolute doddle to replace - just pop them in. This also makes cleaning the blocks/checking them for debris a doddle - pop them out, clean them, pop them back.

Initial set-up of the mounts on the cantilever bosses can be a bit of a fiddle but once that's done you are sorted. I particularly like the way the blocks come at the rims at a 90 degree angle - straight on - none of the arching or swing movement you get with normal cantilevers or V brakes.

I'm a bit surprised that they aren't supplied as original equipment on more bikes but suppose it's cost/the fact that the bikes would then bust price points seen as competitive-critical by bike manufacturers. For something like a fast city bike or a bike used for day rides I'd encourage anyone after nicer breaking to consider them. Red Light is exactly right - it's not just the strength of the braking, it's the modulation and sheer confidence of them. And the fit and forget. I wouldn't put them on a tourer though - although the lack of faff and the sheer bloody ease of changing brake blocks would be great, I'd be too concerned about the hudraulics getting messed up by some accident or daft individual interfering with them. And then getting them sorted on tour would be a pain. But I stress that in normal use you can usually just forget about them - for years and years.

 

[AndyPeace]

Well, watch you don't touch a rotor with your leg after braking on a long descent! (It's a mistake that you will probably only make once ... )

There's got to be limited circumstances where this would happen, go on tell us how you ended up doing this?

 

[ColinJ]

There's got to be limited circumstances where this would happen, go on tell us how you ended up doing this?

Brake on descent, heating up rotor, come to narrow gate across bridleway (there was a big gate but the small one was nearer!), squeeze through gate with MTB, smell burning, pain in leg ...