prj71

Mechanical disc brakes suck. Just barely a step above rim brakes.

If you have ever had or tried hydos you' would realize why...

-Disc brakes with hydraulic hoses to get braking force from lever to pad work better than cable-actuated systems
-Hydraulic systems are more efficient than mechanical disc brakes so you need to apply less pressure at the lever for an equal level of braking power. This means you can get better modulation.
-A hydraulic system is sealed so no contaminants can get in to affect braking performance, and complicated internal cable routing isn’t a problem, whereas it can add friction to a cable setup.

FiftySix

So, the reservoirs are air free? I could hang a disc brake bike upside down for a long period of time and not have air migrate into the calipers?

prj71

I don't ride my bike upside down so it's never a worry.

I know what you are saying, but a few seconds right side up and a few pulls on the brake lever and all is well again. My mountain bike is sitting in my garage upside down at the moment. It's been that way for 2 weeks now as I'm waiting for some new wheel parts to come in. When I turn it over it I know for sure the brakes will be spongy. But once I pull the lever a few times all will be back to normal.

Storing hydraulic disc brake bikes upside down is not an issue unless there is already an existing issue with the brakes (poor quality or damage).

Bottom line here is that all good bikes are going to be disc brakes if they aren't already. The rim brakes will be left on the bikes you buy at Walmart.

Here's just one example. Almost the whole line is disc brakes save for couple cheaper versions of the Domane

https://www.trekbikes.com/us/en_US/b...-bikes/c/B200/

fietsbob

should be a rubber bladder-gasket under the cap, to let the heated oil expand, without letting air in.

Pop N Wood

But I have owned bikes with hydros. Also own bikes with mechanicals discs, V brakes, side pull brakes and even center pull brakes on the Schwinns. I did upgrade all my cantilevers bikes to V brakes.

I love hydros. Had a Remedy 8 with SLX hydros, super nice brakes, made me want to touch myself.

But also really like these Spyre mechanical discs. They absolutely do not suck. And at $45 a wheel with rotors they are cheaper than rim brakes that all these people think are so affordable.

vespasianus

I used to run BB7 brakes and with gore shift cables, they worked really well, but on long steep downhills, they gave up tons to a good set of hydros. I also found them to require much more maintenance than hydros, which you basically don't have to touch once set up. But if I had a disc frame but did not want to spend the money, I could see mechanicals working good enough.

FiftySix

Right, my motorcycles had that, too. But under the bladder-gasket was always a bit of air. I just never got around to hanging my 240 lb. to 540 lb. motorcycles from the ceiling to check out this theory, though.

FiftySix

Sort of self fixing. That's good to know.

cyccommute 

If a brake “sucks”, it’s likely due to the person using it and/or the person installing and maintaining it. I have bikes with cantilever, linear, dual pivot side pulls and mechanical disc. None of them have every failed to stop me when and where I’ve needed them. I even load my some of my bikes with extra gear for traveling...aka touring... and throw myself down hills at stupid speeds for an unloaded bike. Never had a bike that has failed to stop. Never had a brake that even hinted that it wouldn’t stop.

I tried hydraulics. I hated them for the very reason that you say they are “better” than mechanicals. The term “modulation” that many people use with respect to hydraulics isn’t what I would call modulation. Less force needed on the levers means that the brakes are touchy. A slightly too high amount of pressure on the brakes means that the brakes grab harder. That’s not “to regulate by or adjust to a certain measure or proportion; soften; tone down“ to quote the definition of modulation.

Additionally, cable systems...even ones with compressible housing...don’t have that much “give” in the system. To use an arbitrary number, if hydraulic have a efficiency of 100%, cable systems have an efficiency of 99.99%. Even rim brake systems are coming in at 99.9%. The gains in hydraulic systems is minimal at best. Bicycle braking systems aren’t limited by the power they produce but by other limits dependent on the physics.

First, I’ll agree that internal cable routing is an abomination that has never been an advantage no matter where it has been used. That said, Seals fail. Hydraulic systems need to be flushed from time to time to remove contaminants. Air in the system is a contaminant that has a severe impact on the braking performance. Contamination of a cable system has never really been an issue in my experience on my personal bikes. I’ve seen it in other bikes but it is easily and cheaply solved. Cable replacement can be done in the time that it takes to gather tools for a brake bleed.Brake bleeds aren’t all that necessary but neither is cable replacement.

rosefarts

I'll try this. It makes sense and may explain just why it's been so difficult to prevent rubbing.

I haven't heard of this before, I know to shove them back when replacing pads, just like on a car. If the self centering thing is reliable, I may consider changing my opinion.

vespasianus

Honestly, mineral oil brakes need very little maintenance. I have mountain bikes on which I have not touched the brakes in years. The reliability of the current systems are very, very good. I have changed more brake cables than I have messed with hydraulic fluid.

vespasianus

If it does not work, you might either have air in the system or a sticky piston.

WhyFi

Sounds like your fingers need calibrating; mine did, too, when I first made the move to hydraulics. And the first of the three definitions that you copy/pasted is exactly what people mean.

cyccommute 

The reliability of any current brake system, be it hydraulic or cable, is very, very good. I have cable systems that I haven’t touched for years as well. Sure, cables can corrode but the seals in a hydraulic brake of any kind are susceptible to atmospheric degradation. The rate will depend on a number of factors. It can take a long time for a seal to fail or it cant take a very short time. But you are likely to have to deal with some maintenance at some point. Mineral oil brings its own problems in that the mineral oil needed may be proprietary and/or expensive. If the brake is old enough, the mineral oil needed may not be available, given the ever changing “standards”.

cyccommute 

I understand that my fingers needed calibrating but never found that to be an advantage which is why I moved away from hydraulics. As for the definition, “modulation” is not what I would call the action of hydraulic brakes. Trying to “regulate by or adjust to a certain measure or proportion“ something that is extremely touch and goes from off to on with very little input is the very opposite of “modulate”. Hydraulics are powerful brakes but that power has no regulation in my experience. I can actuate a cable brake from just a little slowing to full on stopped without having to think about how much lever power I’m putting into the system. I never experienced that with hydraulics.

WhyFi

25 bucks worth of Shimano mineral oil will service a fleet.

cyccommute 

If that fleet has only Shimano brakes. And that’s only today. Shimano isn’t really known as a company that supports it’s old equipment.

WhyFi

You're saying the same thing as in your previous post, and it's not making me think any different - you were being ham-fisted. You did not acquire the finesse to control the brakes to the best of their capability. You don't need to grab a fist full of lever; I often brake with one finger, 'specially on bumpy stuff. I can feel exactly when the brakes engage, I can adjust the force with which they engage very finely, from very lightly to very firmly. That's modulation.

vespasianus

Mineral oil is mineral oil. I am all for riding what you have - heck some would call me a luddite - but the complaints and fear of hydraulic disc brakes was covered in the MTB scene 20 years ago.

cyccommute 

If the brake truly has “superior modulation”, it should matter how “ham-fisted” I was. If you have to brake with one finger to avoid over braking, the system is just powerful. It’s not easily regulated. I can adjust the force needed to engage a cable brake system...from cantilevers to disc to side pull...in the same manner as you do but I can be as “ham-fisted” as I like and still come to a stop.

WhyFi

Shimano is the 800lb Gorilla, SRAM uses DOT and I don't know/care about Campy users - they can fend for them selves. If you're really worried about not having the mineral oil around in 20 years, buy two refill bottles.

cyccommute 

You are talking to a chemist here. Mineral oil is not just “mineral oil”. Mineral oil comes in many different viscosities and those are going to have an effect based on the design of the system. What effect it has isn’t predictable either. Lighter or thicker mineral oil may work or it may not.

WhyFi

Exactly - it should matter and it does. GIGO.

I don't have to - I do it to have more fingers wrapped around the bars, hence mentioning the "bumpy stuff."

It is. Very.

You're arguing that needing higher actuation force is a benefit? Cool.

vespasianus

You are way over thinking it. Shimano mineral oil works in Campy systems and in Magura systems. People have used baby oil in Shimano brakes for yukes and it works. If you are afraid of mineral oil go SRAM/HOPE/HAYES who all use some sort of DOT fluid.

Ride what you like and be happy.

WhyFi

But what fun is it to not pick the nittiest of nits?