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I am considering buying a new bike and have two models in mind. One features hydraulic rim brakes from Magura and the other has hydraulic disk brakes. Despite searching on the Internet and asking bike repair stores, I haven't found much information about pros and cons of one type compared to the other.

The common points I am aware of:

  • very good braking power
  • relatively hard to service yourself, almost impossible while on the road

The differences I am aware of:

  • I guess that hydraulic rim brakes are more sensitive to rain/mud/etc. (although I am not even sure, given the huge amount of pressure applied)
  • It's easier to remove your wheel with Magura rim brakes (in case of puncture for instance).

Some more specific questions:

  • Does the braking feel similar with both kinds?
  • Ease of service?
  • Ease of finding spare parts in remote places?
  • Difference in braking power?

I'm looking for general differences but a bit of context might help: the bike will be used for commuting and randonneuring, so mostly on roads and sometimes on gravel paths.

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    I'm not sure your common/differences are all 100% correct or maybe too general; e.g. Maguras hardly need any servicing at all, things like replacing pads are pretty easy and adjusting them takes, depending on the model, just 1 or 2 allen keys and can bascially be done anywhere. Also removing a wheel with discs, depending on model, is just sliding it out. With some Maguras you need tools or need to fully deflate the tyre to be able to get it past the pads.
    – stijn
    Jul 29, 2018 at 18:45
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    Hydraulic rim brakes are no longer state of the art and have long been supplanted by disk brakes. They have the same disadvantage of cable-pulled rim brakes: thinning of the rim walls and more even so because the brakepads press the surface with higher force.
    – Carel
    Jul 29, 2018 at 19:56
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    A big problem with hydraulic rim brakes is that hardly anyone has ever seen them, including service shops and the places that sell bike parts. And there's little to recommend hydraulic rim brakes over (simpler, cheaper, lighter) cable-operated rim brakes.
    – Daniel R Hicks
    Jul 29, 2018 at 21:07
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    Western Europe in the past 5 year or so has seen a rise in use of Maguras with the coming of more electric bicycles. They used to be a niche item for trials riding or tandems etc, barely ever seen indeed, whereas now I literally see them every single day. So I'm assuming by now the shops which didn't yet distribute them by now should now how to service them.
    – stijn
    Jul 30, 2018 at 7:34
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    @filaton : A city bike is often left outside or in a shed locked-up with many other bikes. People and bikes move around and rim-brakes may be a better choice in that situation where a disk might get easily knocked, bent and damaged, like some person manoeuvring a bike past and catching the disk with a pedal. Just a thought.
    – Carel
    Jul 31, 2018 at 11:57

2 Answers 2

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Some arguments in both directions:

  • Avoid disc brakes on a bike with quick release (QR) rather than through axles. On the front loosening of QR by brake action may be a safety concern. At both ends it is often difficult to position wheels with QR reliably enough to ensure there is no disc rub. A QR equipped bike might be more convenient with rim brakes.

  • Six-bolt rotor bolts need to be tightened with exactly the same torque. One needs a small torque wrench or key for that. Uneven torque may lead to slightly warped discs and disc rub.

  • It is much easier to keep the brake surfaces of disc rotors clean than those of rims.

  • Riding in the wet may cause brake noise with disc brakes as well. Rain rides on lose surfaces usually kick up enough dirt to the rear disc to cause constant rub and noise.

  • Disc brakes allow much nicer rims. In particular carbon rims.

  • Magura rim brakes require mounting posts like cantilever brakes. There are no levers for drop bars. This rules then out for most road bikes. However, SRAM offers hydraulic rim brakes. *This is not correct, see comment by @stijn.

  • Don't restrict yourself to Magura when considering disc brakes. That they offer the best rim brakes and the best hydraulic system for rim brakes does not necessarily translate to disc brakes. For example, heat stability of their brake fluid might be an issue for discs while it does not matter for rim brakes.

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    For completeness: Magura has an hydraulic rim brake for road bike mounts, and there's (possibly custom) adapters for U-mount -> cantilever mounts as well. Again in the custom space I've seen adapters for drop bars + electronic shifting. And with a bit of luck one might even still find Magura's own drop bar lever from the nineties.
    – stijn
    Jul 30, 2018 at 9:55
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    People have been safely riding disc brakes with QRs for decades. If they were as dangerous as you imply, anybody selling such a bike would be sued into oblivion. There were some problems early on but this really is a solved problem, now.
    – David Richerby
    Jul 30, 2018 at 10:26
  • David, please note my wording: "may be a safety concern". In contrasts I am very direct that it is not a good idea to use QR because of imprecise positioning leading to disc rub.
    – gschenk
    Jul 30, 2018 at 11:33
  • Thanks for your answer! Maybe that was unclear, but I was not necessarily considering Magura for disk brakes :) And interesting point about the QR, I never heard of that before but I guess I have no choice anyway, as most of the bikes (at least those I'm looking at) have QR wheels
    – filaton
    Jul 30, 2018 at 20:58
  • A precisely adjusted and locked QR doesn't let the wheel escape from the fork. Unfortunately many occasional riders lack that skill and use the QR either as a simple bolt or only half-tighten the lever.
    – Carel
    Jul 31, 2018 at 11:47
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Are you talking about a mountain bike or city bike?

I have Magura hydraulic rim and disk brakes on two different bikes. The Magura hydraulic rim brakes are much more powerful than cable brakes but for mountain bike use I would always go with hydraulic disk brakes due to better modulation and better wet weather performance. The rim brakes can also get mud built up and trap leaves and other debris.

With the hydraulic rim brakes I still have to pop out the brake on one side to get a wheel out, this is pretty easy but it is probably less trouble to swap a disk brake.

As for field servicing. Changing disk brake pads is pretty easy. I've never had to bleed either brake and I guess a pipe blowout or something serious would be a PITA in the field.

I don't know any local reseller for Magura rim brake parts here in France. For disk brakes it is pretty easy if you have a common brand.

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    I would rather use your pro disk argument of wet weather performance for the city bike and not the mountain bike: a leisure trip is likely to be cancelled due to bad weather, while city trips (getting back home from work, stocking up the fridge, …) can't wait for roads to dry up.
    – pseyfert
    Jul 30, 2018 at 8:58
  • In my specific case, I'm looking exclusively at touring/randonneur bikes but I wanted to know the differences in a general context. Since I asked the question, I saw that the Magura argument about removing the wheel is not really a good one; as you mentioned, wheels with disk brakes are usually fairly easy to remove, so that would go in favour of them :)
    – filaton
    Jul 30, 2018 at 21:01
  • But in reality who doesn't go out on a city run because they are worried about their brakes in the rain, in general modern brakes and pads provide enough stopping power on city roads providing, like all road users, you make some adjustments for the conditions (less tire grip). I would argue that steep mountain bike trails are more stressful for brakes but I'm not arguing against using disks for city bikes either... just that for MTBing I'd choose disks.
    – DavidG
    Jul 31, 2018 at 9:06
  • Yes, I don't see a major faff difference between the hydraulic rim and disk brakes. I might be worried about getting Magura rim brake parts on a tour though. In reality both brakes are probably fine but you also have an issue of rim wear with the hydraulic rim brakes on a heavy touring bike. Disks are cheap to replace. The principal use case for the hydraulic rim brakes seems to be to upgrade the stopping power of bikes that can't take a disk.
    – DavidG
    Jul 31, 2018 at 9:11

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