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Comment by bsimpson | Hacker News Reader

It's wild that disc brakes are on his bad list (for home mechanics).

Changing the brake pads and burping the lines are both trivial to do yourself. Changing disc pads might actually be easier than changing rim pads.

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It's wild? Disc brake maintenance absolutely sucks.

I like them, they're critical to mountain biking, but to say they're trivial to service? Not sure I can agree with you at all?

Do you work on larger vehicles like cars, trucks or motorcycles? Compared to the brakes on my car the disc brakes on my bicycle are trivially easy.

Why would you compare disc brakes to cars? Why not compare them to the rim brakes they are replacing. An order of magnitude more complicated to maintain

I've gone far into the depths of hell trying to properly set up a pair of cantilever brakes to be performative. Disk brakes any day.

> I've gone far into the depths of hell trying to properly set up a pair of cantilever brakes to be performative.

This! I thought I'd never have to see cantilever brakes again until turns out they were used on kids bikes so had to deal with that. Luckily my child has now grown to a slightly larger bike with hydraulic disk brakes so life is back to being easy on that front.

Bleeding brakes still sucks and requires specific tools. Cars are worse but bikes aren't particularly easy. You need more than a screwdrive and an allen wrench.

If we really want to bring self-maintenance back we're going to have to have more gumption than this, and perhaps a special tool every now and then.

The issue we're fighting isn't the battle against hard maintenance vs easy maintenance, it's against manufacturers deliberately making products that are expendable and not intended to be maintained. Hydraulic brakes are perfectly maintainable, you can even rebuild the whole system at home with a $6 pair of seal picks and a $12 seal kit, don't even need to be OEM seals.

The easiest thing to maintain is cable actuated disc brakes. Changing the pads is trivial and no bleed kit is necessary. The performance is much better than v-brakes as well. Of course, if you want performance hydraulic disc brakes are necessary fo mountain biking.

Bleeding my SRAM brakes requires a special kit that costs $90 [1], working with toxic chemicals (DOT 5.1 fluid), and a procedure that isn't rocket science but I wouldn't call it trivial either [2]. I also find that disc brake pads wear much faster than rim brake pads (I'm on my 3rd set this year), and cost more to replace too. They also are prone to alignment issues and I find myself messing around with them at least once a month to correct rubbing or noise issues. And god forbid you do something really dumb like squeezing the brake while the wheel is detached (guilty) - causing the piston to pop out and fluid to leak everywhere.

Compared to my other bike with rim brakes that I only had to change the brake pads once and turn the barrel adjuster a few times in several years, I would say that disc brakes are much more troublesome to maintain. I think they are worth it for riders who do a lot of descending, especially in the rain, but would definitely not recommend for someone just getting into cycling.

[1] https://a.co/d/im4bOVh

[2] https://youtu.be/8K4ADjuxEqc

Sounds like you’ve got other issues, you shouldn’t need to replace pads or make adjustments that often.

This source says:

> You can generally expect to get 500-700 miles out of resin disc brake pads and 1,000-1,250 miles out of sintered metal disc brake pads. However, how much mileage you end up getting out of your disc brake pads will depend on the weather conditions you ride in, riding terrain, and your braking habits.

That seems a little low to me, but roughly in line with what I have seen. What is your experience?

Forgot to link the actual source of those estimates [1].

Also, in regards to the alignment issues, Chris Froome has also complained of similar issues [2] with disc brakes. He’s a seven time Grand Tour champion, is on the board of Factor bikes, has an army of professional mechanics to maintain his bikes for him - and he still runs into issues. So not just me.

[1] https://prodifycycling.com/bike-disc-brake-guide/

[2] https://road.cc/content/tech-news/chris-froome-still-has-dis...

1. SRAMs bleed kit is nice, but there are many affordable kits. 2. DOT 5.1 fluid isn’t dangerous, just protect your eyes and immediately wipe it off paint or skin. 3. Write down the bleeding instructions as a checklist. 4. Most disc noise can be quickly solved by using a rag on the rotors or pads. 5. If you have frequent rotor alignment issues then the wheel likely needs truing.

> I think they are worth it for riders who do a lot of descending, especially in the rain, but would definitely not recommend for someone just getting into cycling.

I think this is the takeaway worth reflecting on. Hydraulic brakes are perfectly maintainable if you can be even slightly bothered, but it is a choice you're making to take that responsibility on. As far as adjacent skills required for the hobby of cycling is very approachable, but that said if you want to go mountain-biking and you want hydraulic brakes, you get to make that choice.

> I also find that disc brake pads wear much faster than rim brake pads (I'm on my 3rd set this year)

This seems to be a user error, because the exact opposite is usually true. Rims are much closer to the ground, and therefore are much easier contaminated with mud etc.

> squeezing the brake while the wheel is detached (guilty) - causing the piston to pop out and fluid to leak everywhere.

Again, user error. Just a simple lever pull does not do this, you have to deliberately pump the levers for some time for the pistons to pop. (Actually, simply removing the wheel should not even cause this because it is the brake pad itself that pushes the pistons back, not the rotor.)

And if you don't like toxic chemicals, there are many brakes that have mineral oil in them, which is not toxic and super easy to work with...

> This seems to be a user error, because the exact opposite is usually true. Rims are much closer to the ground, and therefore are much easier contaminated with mud etc.

It’s odd that you would assume user error despite knowing almost nothing about the gear I’m using or conditions that I’m riding in. Do a bit of searching online and you’ll see some people claim disc brakes last longer [1], and some people claim rim brakes last longer [2]. My personal experience is that rim brakes last considerably longer - and I think that’s mainly just due to the fact that they are so much thicker than disc brakes. I get about 2000km on my disc brakes vs 4000km on my rim brakes. How much mileage do you get on disc vs rim brakes?

[1] https://wheretheroadforks.com/disc-brakes-vs-rim-brakes-pros...

[2] https://www.bikeforums.net/commuting/1142311-how-long-do-you...

> How much mileage do you get on disc vs rim brakes?

Mileage isn't comparable for brake wear, what matters is time spent braking.

I'm on the first set of rim brake pads on my 2006 road bike, probably over 10K miles! But that's because it's a road bike where I do long rides mostly in steady state, sometimes hours without braking. So the miles and years go by without much brake wear.

On my mountain bikes I get 2-3 years out of the disk brake pads, not sure of mileage but it'll be low. My average MTB ride is 5-8 miles vs. my average road bike ride of 50-70 miles.

Out of this I wouldn't say the rim brakes last longer, it's just that on the mountain bike I'm constantly on the brakes, often hard, so it's not even remotely comparable.

That said, hydraulic disk brakes are pretty much an absolute requirement on a mountain bike if you're riding in any kind of terrain, so it's a moot point. I wouldn't want a rim brake mountain bike even if you paid me to drive it!

Whereas on a road bike I don't care either way, the brakes aren't that important.

Yup, for what it’s worth I ride a road bike in a mountainous area - so my brakes see a lot of use. The 2000km vs 4000km estimates above are for similar riding conditions on both bikes.

I agree that disc brakes are more important for mountain bikes than road bikes. Disc brakes certainly feel nicer to use, but about the only time that rim brakes feel insufficient to me on a road bike is descending in the rain. And even then it’s manageable if I just maintain a slower speed on the descent.

Rim brakes are downright deadly on a road bike if you have carbon rims and are descending.

FWIW, my Shimanos use mineral oil. There's a little funnel you attach at the handlebars, and flick the lines to burp them. I've had this bike for a decade, and I can't remember the last time I had to do more than that to keep the lever feel strong.

The pads are held in place by a cotter key, so it's impossible to misalign them. You couldn't move them if you wanted to.

>Bleeding my SRAM brakes requires a special kit that costs $90 [1], working with toxic chemicals (DOT 5.1 fluid)

This is why you don't buy SRAM. Shimano (which is a much bigger mfgr) only uses mineral oil. And there's lots of 3rd-party kits that cost a fraction of that.

Either you do a LOT of riding to need to replace your pads that often, or SRAM pads really suck. I haven't changed my pads on my Shimano-equipped bikes yet, and one of them is 4 years old. I certainly haven't had alignment issues, unlike my old rim-brake bikes that needed constant fiddling to stop rubbing.

I’ve ridden about 7,000km so far this year (about 5,000km on the sram disc brakes). Most of that is in the mountains, so I use the brakes quite a bit. I’m also not the lightest rider in the world. As mentioned elsewhere, I get about 2000km on the front brake pads, whereas I’d estimate I got double that on rim brakes. I’m curious how many miles have you put into your brake pads, and in what sort of conditions?

Also as mentioned in another comment, there’s a video of Chris Froome complaining about pretty much the same alignment issues that I’ve experienced. So I don’t think it’s just me. I believe he was on Shimano at the time.

I would have preferred Shimano but at the time we were in the midst of a bikepocalypse and SRAM was all that was available in my size/target budget.

>I’m curious how many miles have you put into your brake pads

I don't know: my bike doesn't have an odometer. I've never seen one that did.

It's not uncommon to use a GPS to log rides. Before GPS became commonplace, there were cycling computers that could estimate your distance based on the number of revolutions your wheel made (as measured by either a magnet on a spoke passing over a sensor, or an accelerometer).

People using bikes as daily transportation don't normally use this stuff.

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