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I'm 195cm and 95kg and today was the second time (in one year) my mechanical disc brake pads burned down and had to replace them. The guy in the service told me that mechanical disc brakes are not that good. Is it really the case, the hydraulic brakes are much better? Or I'm really doing something wrong? (I was always told that I should only use the brakes before the corners when I descend, but when I come down from the hill and it is very steep, I just can't do that..)

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  • 4
    Are you dragging your brakes on downhills continuously? This could be partially a technique thing. How steep is your descent (either drop/run or gradient, or point it out on strava)
    – Criggie
    Oct 8 '21 at 22:23
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    Is the problem that your brake pads are wearing out quickly, or that they are overheating and becoming less effective?
    – bertie
    Oct 9 '21 at 2:16
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    Was he saying that all mechanicals are not as good as all hydraulic (wrong), or was he saying your brakes are not as good as a hydraulic he was suggesting? The question should not be about hydraulic or mechanical, its about if better brakes will make a difference, then you can discuss what type.
    – mattnz
    Oct 9 '21 at 3:21
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    @Criggie around 12% descend for ~4 km. The road was narrow and new for me, with many sharp turns so I had to be careful. I already changed my brake pads to semi-metallic ones. My rotor is SM-RT56
    – uiux
    Oct 9 '21 at 8:55
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    Dragging brakes is detrimental to the brakes with any vehicle. Short & controlled braking periods with release is the better technique.
    – Carel
    Oct 9 '21 at 15:14
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Disc brake type should not affect pad wear, but does affect how hard you can brake. Hydraulic disc brakes tend to be more powerful than mechanical disc brakes.

Both mechanical and hydraulic disc brakes can overheat, leading to rotor "glazing" where pad material is left on the rotor, causing a slick surface and leading to poor braking performance.

Two general guidelines to increase braking power and resistance to overheating are:

  1. Switching from resin disc brake pads to metallic disc brake pads (more even heat distribution)
  2. Larger diameter disc rotors (more surface area for cooling)

If you are satisfied with the power of your brakes as-is, I would not consider replacing the brake pads twice a year excessive, depending on the type of riding. Brake pads are a wear item and need to be replaced periodically. It is a simple service and worth learning to do yourself. I have replaced the brake pads on my mountain bike three times this year, riding in wet and dirty conditions.

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  • It sounds like you’re saying that both hydraulic and mechanical disc brakes can overheat. That is correct. In particular, the rotors overheating and possibly warping can happen on either type of brake. If you brake for really long, hydraulic fluid can also boil, but I am under the impression that the rotors would show issues before your brake fluid did. Also, re metallic pads, is it actually better heat distribution? I thought metallic pads have more bite.
    – Weiwen Ng
    Oct 8 '21 at 22:41
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One way in which mechanical disc brakes typically differ from hydraulic is that the mechanical discs have one pad in a fixed position and only one that moves, whereas in the hydraulic system both pads move. It is possible that in your brakes, the fixed pad is not adjusted properly and is too far from the rotor, causing substantial drag on the moving pad before the rotor moves far enough to contact the fixed pad.

This can cause excessive wear on the moving pad as well as potentially overheating that pad. It's an easy problem to diagnose by just looking at the pads and seeing if the moving side (farther from the wheel) is much more worn than the fixed side pad.

Alternatively, even if the pads do not overheat, normal wear on the fixed pad can increase the distance from the rotor to the point that overall braking power is compromised. This is easily fixed by adjusting the position of the pad as it gets worn.

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  • Not all mechanical disc calipers are single-sided; double-sided models are available, including the TRP Spyke and Spyre.
    – bertie
    Dec 25 '21 at 1:11
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No, hydraulics aren't better, all disc brake suffer from ridiculously low pad life.

Disc brakes have pretty crappy pad life. You may be able to extend pad life by using sintered metallic pads as opposed to using organic resin pads. However, then the rotor life suffers, being far worse with sintered metallic pads.

I am 106 kg, and have a tendency to brake hard using only the front brake. My organic resin front disc brake pads lasted only 2000 km when riding only in dry conditions. That's the worse pad life I have ever seen on any kind of brake. For example, rim brake pads last in excess of 10 000 km if riding only on dry conditions, and even 3000 km can be expected if riding in all kinds of conditions, never avoiding riding because of rain. 3000 km is the worst pad life I have ever had on rim brakes, and the 2000 km disc brake pad life is way below that.

The actuation mechanism (hydraulic vs cable) doesn't matter. The pad type is the only thing that matters. Also how much you weigh and how hard and how often you brake are variables in pad life.

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  • I've seen that on hydraulics disc brake pads there is a cooling fin too, does that count much? (it is interesting I didn't see that on any mechanical disc brake pads).
    – uiux
    Oct 8 '21 at 16:55
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    The cooling fin might be able to help if the problem is too high brake heat. If you can only choose between hydraulics having cooling fins or mechanical brakes not having cooling fins, then obviously the hydraulics are better, but not because of the hydraulic fluid but rather the cooling fins.
    – juhist
    Oct 8 '21 at 17:10
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    What has your low pad life to do with overheating which was the topic of the question? Anyway, just buy better pads, my semi-metallic TRPs supplied with the calipers are still working well after 7.5k km. Many of them off-road.
    – Vladimir F
    Oct 8 '21 at 18:53
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    Also improve your technique, use both brakes!
    – Carel
    Oct 8 '21 at 18:56
  • Pad life is unrelated to the question and is also a non-issue in general. I doubt many people are covering over 2000km in a single ride, and if you are, carrying extra brake pads is something you should be doing regardless…
    – MaplePanda
    Oct 8 '21 at 20:21

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