53

Hydraulics are used on higher end systems, cables are often a sign of a cheap brake set, so your observations are correct regarding "professional" bikes. However there are very good cable disc brakes (e.g. Avid BB7's) that are the exception that proves the rule. . Cables have the disadvantage of friction that hydraulics virtually eliminate. It is ...


25

What you experienced was brake fade. There are two reasons why it happens: The fluid inside the brake boils releasing gas into the system which makes the brakes feel spongy and then non-existant. The pad and rotor heat up sufficiently to not work, this feels like you are applying the brake but it doesn't work. You look to have experienced the first. This ...


22

Usually, singles need to have horizontal dropouts so you can take the chain slack by adjusting the rear axle position. That means that any brake that is attached to the frame will "go out of position" when you adjust the rear axle position. That is, by the way, the reason why some horizontal dropouts are not quite horizontal, but diagonal: to be near-...


22

First of all you need to tell the LBS (local bike shop) that the disk can be "fixed". Then you need to find another LBS because they are either amateurs or are simply trying to make you buy stuff that you don't need. You need to remove the oily disk from the bike and use a bike degreaser or alcohol on it to remove all oil. Rub with a clean dry cloth or ...


21

In addition to @mattnz's response; most cable disk brake systems work by operating one pad only - and squeezing the rotor onto a stationary pad. This means that as the pad wears down, you typically have to wind in the moving pad (usually the outside one) to keep the right bite point. Hydraulic systems usually have opposing pads that self adjust for central ...


19

Since bikes are usually shipped to the dealer with the wheels disassembled from the frame, the disc calipers often each have a plastic separator pressed into them that serve to prevent lock-up during shipping. The Hayes company even puts their brand logo on theirs. Since these are removed during assembly, you might be able to ask a repair person at your ...


18

It's not for hand signals. "Left hand only" signals were originally designed for cars. You couldn't use your right hand out the window, so you could only use your left. Using both hands to properly signal on your bike is far more clear. It's used on motorcycles due to the fact that the throttle is on the right hand, so you want to keep that engaged at all ...


16

Yes. Disc brake rotors can warp a little in use, or get bent from impacts and straightening them is routine maintenance. The basic procedure is to find spots where the rotor is bent inboard or outboard, and carefully incrementally bend it back. There are tools made for this purpose (e.g. Park tool DT-2) but the job can be done with a large adjustable wrench....


14

Simply put a bigger rotor provided better braking, and a four pot caliper provides better braking - better meaning more, and more control (Everything else being equal). For the same force between the disc and pads, a bigger rotor generates more torque on the wheel - i.e. more stopping force. It is running though the pads faster, generating more friction ...


14

There are two risks to turning your hydraulic brakes upside-down. The brake system isn't filled to overflowing with hydraulic fluid: there's likely to be a small air bubble. Normally, this sits at the highest point of the system: the oil reservoir at the brake lever. There, it's not compressed by the piston when you brake, so it can't interfere with braking....


12

Usually what you do is disconnect it at the lever, install the lever to the bar, and run the hose up from the caliper end. Because it's sealed on the other end, no more than a few drops of fluid will escape. Then once it's through you can size the hose by turning the bars as far as they go while holding the hose up to the lever and finding the length where ...


12

No, the thermal conductivity of brake hose/fluid is way too low. I've run the numbers on this -- very roughly to make the calculations simpler. I've assumed the hose isn't cooled by airflow for some reason and a solid hose or equivalently that the fluid has the same thermal conductivity. Even the lever is assumed not to lose any heat to the air. All ...


11

Here are a couple of downsides of both types, that I have witnessed. Hydraulic. Leaking oil tends to get into the pads and rotor, rendering the first useless and the second in need of professional cleaning. Mechanical. Cable failure is very perilous. Essentially one moment you have full stopping power, the next moment the brake is disengaged fully. ...


11

Cable discs rule if you are riding a lot of third world. I am a million miles away from a shop, access to the oil, etc. A hydraulic failure would be disaster, whereas the worst thing that will happen with a cable disc is a lose bolt/need for readjustment. As smooth as hydraulics are, the fix of a failure when in the middle of nowhere (whether third world or ...


11

For a city commuter bike, don't bother with disk brakes - go for simple rim brakes. You'll want the reliability over all else. You don't need disks for most types of road cycling, as the limiting factor for grip is likely to be your tyre anyway. As regards shifters, go with whatever is comfortable for you. I like the combination of brakes and gear levers in ...


11

The comments OraNob and Batman said are spot on. A cable cutter uses shear force (focused crushing) to cut through the metal wound wires in a cable housing but still requires some clean up because of this. This is why you need to go back and reform the inside wires with an awl and clean up the edges with a file or sanding pad. A plastic hydraulic line can ...


10

I have or have had bikes with mechanical rim brakes, mechanical disks (shimano deore), hydraulic discs (also shimano deore) and recently hydraulic rim brakes (Magura hs33). The experience I had says that: The force you have to apply depends on brake-system preload / elastic constant (lever spring + actuator spring), cable friction, and actual, braking, pad ...


10

The least you need to do is bleed the brakes to remove trapped air. It's best though if you completelly change the fluids and bleed. You can do that in an LBS, or yourself if you have a bleeding kit and know how to do it. The reason for the behavior you described is that air is trapped in the system and makes things mushy and unpredictable. The fact that ...


10

Most likely cause if the disc and pads are contaminated. What did you wash it with? Many cleaners leave a residue. Worst case the pads need replacing. The discs should be well cleaned before installing new pads - Use a solvent such as brake cleaner, methylated spirits or Isoprop alcohol, and rub the discs to be certain no contamination is left on them. ...


10

I believe it is not worth trying it. You risk contaminating, scratching, or bending your rotors, as well as scratching or cracking a brake pad. Consider also whether there are bigger problems with your bike setup if it's too much hassle to remove your rear wheel to change your brake pads — how often does that happen: every 2–3 thousand kilometres? Is there ...


10

I've had my fair share of hydraulic brake woes this year so I'll list the things I'd check - I am aware that you've done some already. Firstly some questions though: Are these brakes using mineral oil or dot fluid? If it's dot fluid, when attempting to bleed the system you may want to take extra care and de-gas the liquid like with Avid brakes. The comments ...


9

Bedding-in is a common process with new disc brake pads. Disc brakes were developed much earlier for motorcycles and cars, from which the technology and the terminology has been transferred to MTBs: see https://ebcbrakes.com/articles/motorcycle-bed-in/ and http://www.centricparts.com/files/White%20Paper%20Revisions%204-2012/Centric%20White%20Paper%20C3-2012-...


9

As mentioned in comments you most likely applied the brake without the disc between the pads. The pistons advance and do not return all the way to their original position - this is how hydraulic brakes automatically adjust for pad wear. The pistons can be pushed back in. Remove the pads then use a tire lever to push the pistons back in. Then replace the ...


9

TL;DNR - single finger levers have little (if any) advanatage and some disadvantages. Most people do not start out cycling with XT/Ultegra quality bikes and therefore (do not) start out on bikes that have brakes good enough for one finger control. Even today, many low end disc brakes cannot reach full braking potential (i.e. wheel lock), with one finger. ...


8

My mechanic claims that the brakes cannot be switched. You route the cable/hose to the lever on one side of your bars instead of the other. Maybe you have to swap mismatched levers from one side of the bars to the other. Either way, it's a trivial change. Get a new mechanic. So should I get used to it? Even though I'm American, I wire all my bikes so ...


8

I just had to look this up for a friend, who accidentally completely closed them. The recommended way, taken from "Zinn and the art of Mountain Bike Maintenance" is as follows. "Sometimes the pads in hydraulic disc brakes can rub because the pistons get pushed out too far, especially if the lever is applied without a rotor or spacer between the pads. You ...


8

There are 2 types of hydraulic brake systems, referred to as open systems and closed systems. Open systems have a reservoir, with a cap, usually on the brake lever, above the master cylinder. These systems, when proper care is taken, can have fluid added, or hoses trimmed without rebleeding the brakes. Closed system brakes, like most older Hayes brakes, (...


8

I store my bicycles this way for the summer (winter fat tyre bikes) and winter (non-commuter mountain and road bikes). I haven't ever had any issues with this and the shop I worked at previously stored all the most expensive bikes this way as well (less expensive bikes were warehoused). I haven't ever had any issues where my brakes suddenly didn't work ...


8

From Shimano Service Instructions: When turning the bicycle upside down or on its side the brake system may have some air bubbles inside the reservoir tank which are still there when the reservoir tank cover is replaced, or which accumulate in various parts of the brake system when it is used for long periods. The M755 disc brake system is not ...


8

The official answer from Shimano as of now is no, as per their road hydraulic systems compatibility chart. Someday there may be flatbar road hydraulic levers that make their way onto a new version of that chart, but for now bikes like that just come with conventional MTB/hybrid systems. There may be combinations that work acceptably, but they will be hacks ...


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