If I could, I’d completely ditch any disc brakes for rim brakes; but it’s getting harder to find decent rims, hubs, and frames compatible with rim brakes. Such a shame. I wrote a lengthy post why I detest them, but disc brakes are unavoidable FOR NOW.
Hydraulic disc brakes seeems far superior to mechanical disc brakes: they -obviously- provide more braking force, cable maintenance and replacement almost unnecessary, and they are lighter. There are some “boutique” brands, such as TRP, makes decent mechanical brakes, but they’re not anywhere in cheap territory.
There are millions of things wrong about disc brakes, so why move to a already inferior technology, when there seems to be an inferior technology that sucks less on paper?
Well, I have my reasons:
Hydraulic disc brake pistons is a joke
My wife has an old Bianchi with mechanical disc brakes, probably first ever disc brake manufactured by Shimano. With entry level rotors. Do pads rub? Never!
On any disc brake, be it for cars, bikes or motorcycles, pistons retract by springing force created by a rectangular o-ring. Kudos for rubber makers, but every vehicle I drive, I got certain amounts of brake rub. Even with a little bit aged racing calipers.
With bikes, this is very annoying, because you hear it clear and loud, and also destroys your effort, compared to nothing even with very underpowered car. Cars for instance, have much better caliper designs, pistons protected by rubber boots. They fail after considerable amount of abuse. Bike calipers? They are made to fail. Master cylinders in cars huge compared to tiny and flimsy brake levers on bikes, having few cc’s of fluid. Car and brake manufacturers can position the pads far enough from the disc (rotor) because there is enough mechanical advantage and pedal travel to compensate, whereas bikes don’t. On bikes, pad clearance between the disc is rarely a mm, or less.
But there is one bigger problem that causes unavoidable brake rub…
When pads worn, pistons have to move closer to disc, otherwise your brake lever travel does not create adequate braking force, or mechanical advantage. So, there is a compensation mechanism, for cars, too: pistons slide inside those rectangular o-rings that retracts pistons when you loose the brake lever. However, this never seem to work right. As a consequence, pistons stick out too far, and push pads to rotors, creating even less gap. As a result, your brakes rub.
With mechanical disc brakes, you can set the tolerance. You’ll lose some braking force, but at least for me, better than rubbing brakes.
Hydraulic disc brakes are expensive and not much repairable
Shimano hydraulic brakes have no repair kits for calipers and levers. Sram makes those kits, but trying to repair them sometimes costs much than buying brand new brakes. If you buy decent
Brembo calipers for your cars, you can use (and abuse) them for decades, just replacing moderately priced (compared to whole kit, which is not cheap by any means!) pistons, o-rings, pins, etc. I’m OK for expensive parts, UNLESS I know they are repairable at a reasonable cost. That’s what quality is. Rich people get richer, or stay rich, because they make good choices. Buy expensive things that keep their value. While middle-class people buy BMW’s, and lose half of their income to maintain a car that wouldn’t worth a dime after few years. Rich people order custom bikes makes to their size, and that bikes becomes a classic, probably worth 5x then their purchase price. Middle class people buy plastic bikes from a volume manufacturer that cracks, or rots in time, which has no value without advertising and propaganda methods, based on methods of great propagandist but an absolute horrible guy, Goebbels.
When rim brakes was a thing, I bought 2 sets of Tektro brake levers. They are excellent: works with both rim brakes and mechanical brakes, lighther then more expensive Deore levers at the time, and quality level is amazing. If you crash your bike and break your levers, you get a new one. With hydraulics, you generally get a matching set, which is expensive.
Some people will say hydraulic hoses are indestructable, but with mechanical disc brakes, you have to replace cables. Indeed, so. But there is a downside to that: hydraulic hoses are mind-bogglingly expensive compared to what they are. I occasionally change parts amongst bikes. Once you cut hydraulic lines, they won’t fit to a bigger bike. So I cut them very long, and looks funny on my bike. On the other side, I use premium Shimano cables. They’re very fairly priced, and obliterates any boutique items that are 5x more expensive. If you maintain them well, they last very,very long time. One extra advantage: they come in with lots of nice colors!
Mechanical disc brakes are maintenance-free (compared to hydraulics)
If you have hydraulic brakes, you have to keep a bleeding kit, brake fluid, various pads while servicing them, and this is hardly a single man job, due to bleeding them is awkward. With mechanical disc brakes, you just need cables and ferrules, if you like.
Mechanical disc brakes does not compensate for pad wear, so they must be aligned now and then, but at least, it works! Hydraulic disc brakes needs piston cleaning and orientation quite frequently, fluid changes and they never work right, especially when they age.
They just work
I’m not a racer; so I’m ok with reduced performance and a few grams of extra weight. I expect my equipment to work consistently.
Mechanical calipers and levers are very basic, there is no rubber to deform, no fluid to lose its characteristics, to seal to blow up. This gives me a sense of security, while with hydraulics, I know there are millions of things that can go wrong.
Why not cable-actuated hydraulic disc brakes ?
TRP makes disc brakes that drives a piston on the caliper. This design basically moves the master cylinder out of brake lever to caliper. They’ re expensive, which negates the advantage of using cheap brake levers. But that’s not it: it’s a good idea implemented wrong: the huge problem with bicycle disc brakes is the hydraulic caliper itself; not brake lever: they work in dusty conditions, rotor to pad distance is absymal so brakes rub all the time. They should do it just the opposite: a hydraulic actuator driving a mechanical caliper which has no spacing issues, don’t get lazy pistons because of retraction o-rings and don’t die off early because of dust and debris.
Am I being too narrow minded ?
Fortunately, no. I’ve always been very open-minded, maybe too much for my own sake, and continue to be so. I like trying new things when technology involved. But I have no tolerance for going backwards. Yes, hydraulic disc brakes works almost perfect for cars; but for bikes, almost everything designed so badly from ground up. I believe there may be really top-notch hydraulic disc brakes perform well. My current brake setup is Deore, which is something like Ford, compared to cars’ price range. Yet hydraulic brakes on a Ford works flawlessly, so why do I have to buy a Mercedes (like, XT set) to expect it to JUST work? When I could have Fiat brakes, like Tektro mechanicals, to work without any problems?
I hope someone will come up with a decent design from the ground up in the future, because PROPER hydraulic brakes have undeniable advantages compared to any braking solution. Yet, not ready for today.
