An endless FAQ to road disc brakes

An endless FAQ to road disc brakes
Love it or hate it, disc brakes on drop-bar bikes are here to stay. With all major drivetrain manufacturers now committed to the cause, and an increasing number of brands pushing the advanced brake system, there ’ s a high prospect your following bicycle ( or motorcycle after that ) will feature disk brakes. however, the total of advantages they offer do bring about a phone number of quirks and unique maintenance demands .
The lapp questions regularly appear with about every mention of disc-equipped bikes, so we figured it ’ s clock time to answer them. This article may not be the most stimulate to read, but we hope it ’ mho at least useful. Let us know if we missed anything ; This is the endless FAQ to road disk brakes, after all, and despite the length, there ’ s constantly room to add more .
Last updated: August 16, 2019 .

The Basics of Road Discs

What is a disc brake?
Modern Dura-Ace disc brake
Disc brakes have been around on bicycles for a properly sum of time – adenine early as the 50s, in fact. Mountain biking actually brought phonograph record to popularity, and they ’ ve been the standard braking system there for about twenty years. But in terms of what makes them different, it ’ sulfur truly quite simple. like to the brakes found in modern cars or motorbikes, disk brakes move the braking airfoil from the rim to a dedicated metal ( normally steel ) rotor attached to the hub – that ’ s all .
In concept, disc-brake calipers aren ’ t all that different from rim-brake calipers, either, except that the caliper bodies are much smaller, and the pads are made of much harder materials than the versatile rubbery compounds used in rim brakes .
Mechanical versus hydraulic disc brakes: what’s the difference?
TRP Spyre mechanical brake
A mechanical phonograph record bracken is much like a traditional rim brake, using a standard road bicycle brake lever and cable television that are connected to the brake caliper. When the pry is pulled, the cable actuates a piston that pushes a single brake pad, flexing the rotor enough for it to get squeezed between the moving brake embroider and a fixed one. Some mechanical magnetic disk brakes, such as the TRP Spyre, exercise by pushing both brake pads simultaneously against the rotor .
A hydraulic brake ( pictured at the top of the article ) is more like what a modern cable car would use, where fluid is used to transfer force. here, fluid is stored in a reservoir called the headmaster cylinder, which resides inside the brake lever body. When the pry is pulled, it pushes fluid out of the chief cylinder and through the brake hose to the caliper. That fluid then pushes the caliper pistons ( to which the pads are attached ) against either side of the rotor .
Why is hydraulic braking superior?
mechanical brakes are highly dependable, however the cables and caparison are less effective at transferring world power from the lever to the caliper, they ’ re more susceptible to contaminant, and have to be manually adjusted as the pads wear .
By contrast, hydraulic magnetic disk brakes automatically compensate for pad break, they ’ re generally lighter, and they ’ re in full sealed from the elements. additionally, the hydraulic design produces less mechanical friction in the system, and impressive impel amplification can be engineered in, besides, meaning a light feat at the pry equates to a hale lot of braking pull generated at the roulette wheel .
Can I turn a mechanical brake lever into a hydraulic one?
TRP Hy/Rd hydraulic brake caliper
Simply put, no. however, you can connect a mechanical brake lever to some hydraulic calipers. Options are limited for this, but both TRP and Yokozuna offer such a thing. Both of these feature a hydraulic caliper where the maestro cylinder is in the caliper torso itself. Your mechanical brake pry pulls a mechanical cable television, which pulls on the piston perch at the caliper. It ’ randomness still a compromise, with cable friction losses and increased slant as issues. But if you ’ ra looking for better brake performance on your mechanical disc-equipped bicycle, or looking to re-use some existing shifters on a new bicycle, it ’ s a feasible option .
How much heavier is a disc-brake system?
This is a street fighter question .
Simply comparing something like the Shimano Dura-Ace R9100 brake levers and rim-brake calipers ( including an estimate slant for cables ) with the equivalent disc-brake system, you ’ ll see the magnetic disk brakes are approximately 200g heavier, accounting for cables, house, and brake hoses .
however, disc-brake hub are besides heavier since they require interfaces for mounting the rotors, and disc-compatible wheels are besides heavier since they have to handle more flex loads. As a solution, disk wheels are typically built with a higher talk count, crossed address lace and frequently chummy gauge spokes, excessively. Some of that can be offset with a lighter rim, since it no longer has to include a brake come on, but it ’ mho hush a net profit in mass .
conversely, some – but not all – modern disc-compatible road frames are actually lighter than their rim-brake counterparts, but the stiffer thru-axles normally paired with them add some of that weight unit back. Overall, many top-tier brands claim the system of weights difference between rim-brake and disc-brake frames is between 30-90g .
Taking everything into bill, you ’ re typically looking at a 300g disadvantage with disk brakes, and that ’ s truly a best-case scenario. More much, and where stricter budgets are involved, the weight gain is typically closer to 500g ( 1.1lb ) .
That ’ s likely to change over the coming years, though. For model, there was a turning distributor point for disk brakes in cross-country mountain bike racing about 15 years ago, where phonograph record brakes as a arrant organization ( including wheel weights ) became lighter than equivalent rim-brake options. While we may never see that happen on the road side, for indisputable the gap will continue to narrow .
I can already lock up a wheel with rim brakes, so why should I even bother with discs?
Being able to lock a wheel is not a sign of great braking operation, and yes, ultimate braking ability is dictated by the sum of traction your tires have on the road airfoil. however, disk brakes provide finer dominance of your braking power fair before lock-up, which is where you get the most effective brake. Better known as modulation, this ability to more precisely apply the power reduces your brake distance. In a rush, this allows you to brake late into corners and have the confidence to carry more speed out of them .
Those who ride in moisture conditions will besides benefit from improved braking confidence careless of the weather, adenine well as reduced alimony. about all hydraulic phonograph record brakes will automatically adjust to pad wear, and you won ’ triiodothyronine suffer from wear rims due to gritty brake .
Hydraulic magnetic disk brakes require less hired hand attempt, excessively, meaning a single finger is often all that ’ sulfur needed to keep your speed in check .
Enve SES 4.5 AR Disc
last, there are the engineering freedoms disc brakes bring. By removing the brake caliper from the branching crown or seatstay bridge, manufacturers have been able to greatly increase sur clearance and improve skeleton conformity. Likewise, hydraulic phonograph record brake lines can be routed with tighter bends than mechanical cables and housings, which greatly eases routing complications. Wheel manufacturers besides have the potential to build lighter rims ( although in practice, those differences are very minor at deliver ) .
But yes, there are celebrated disadvantages to disc brakes. They ’ ra heavier, the initial frame-up is more complicate, and they have their own idiosyncrasies. And yes, the engineering is silent more expensive .
Are disc brakes more or less aero than rim brakes?
All things being peer, disk brakes alone are marginally less aero than rim brakes. however, an increasing number of bicycle brands, such as Giant with their Propel Disc, claim that by removing the clutter of rim brakes, the aero effects of a magnetic disk rotor can be balanced out .
More importantly, some of the fastest aero bikes have traditionally used rim brakes that perform with doubtful quality, not to mention the fact that braking operation on carbon paper rims isn ’ thyroxine arsenic good as on aluminum ones. Regardless, phonograph record brakes are opening up possibilities for aero benefits elsewhere on the bicycle, and we ’ re only starting to learn how .
Can I race with disc brakes?
Discs allowed for racing
Come the 1st of July 2018, phonograph record brakes are authorised for use in all UCI-governed events. And given barely about every amateur event, including Gran Fondos, looks to the UCI rules for guidance, disk brakes are now widely accepted .
Is the industry going to force us onto disc brakes?
not arsenic hanker as rim-brake bikes are distillery being sold. There ’ s no denying the tendency toward disk brakes on road, and a few brands, such as Giant, have been highly outspoken in stating that rim-brake bikes have a limited life .
even if the boastful brands shift off from flange brakes, which will take a number of years, you ’ ll still be able to work with any total of custom-made builders, or smaller brands, to get a bicycle with rim brakes .
Yes, more and more disc-equipped options will become available over the adjacent couple of years, and it ’ ll come at the cost of fewer and fewer rim-brake bikes. But if you ’ ve got a rim-brake bicycle nowadays, or you ’ re looking to buy one, it won ’ thyroxine become disused any time soon .

Road Disc Installation and buying basics

Can I fit discs to an existing bike?
Chris king R45 rim brake hub
Simply, no. Disc brake calipers require specific mounting points on the pitchfork and frame, while the wheels need specific hubs onto which the rotor can be installed. While there were a handful of older ( most cyclocross ) bikes manufactured during the nascent days of phonograph record brakes that could accept either format, the find that you can install phonograph record brakes to your existing rim-brake motorcycle are highly modest .
If I imagine my wheel as a disc, surely I have disc brakes already, don’t I?
In theory, yes. however, the advantages of magnetic disk brakes lie not in the size of the rotor, but how efficiently push is transferred from the lever to the braking come on. The friction coefficients of carbon fiber and aluminum rims aren ’ metric ton about ampere full as steel disc-brake rotors, and rim-brake calipers and housings are much more prone to power-robbing flex than compress hydraulic disc-brake calipers. Exceptions do exist, such as some specially treated rim-brake sidewalls and hydraulic rim-brake calipers, but for the most part, it ’ s actually not the same thing .
What is the difference between a Center Lock and six-bolt disc rotor?
six-bolt versus centerlock rotors
These are the two common ways to mount rotors to hubs. Center Lock uses a splined interface to hold the rotor, and a lockring ( which typically uses a cassette lockring cock, but sometimes an external bed bracket creature ) secures it in home. It ’ s an elegant system introduced by Shimano and now offered by the likes of SRAM and Campagnolo, besides .
typically found on cheaper bikes, six-bolt rotors are simple and see the rotors attach to the hub with six bolts. A Torx T25 is the common tool for these bolts .
You can identify either rotor type by merely looking at either the hub or rotor. A splined interface is Center Lock, and six-bolt is, well, six-bolt .
centerlock adaptor
It ’ south worth mentioning that six-bolt rotors can be installed on to splined hubs with the proper adapter, but the invert international relations and security network ’ triiodothyronine possible .
What is Ice Tech?
Ice Tech is the estrus management engineering built into specific models of Shimano brake pads and rotors .
In the rotors, Ice Tech refers to a three-layer rotor construction, with an inner aluminum level sandwiched between stainless steel braking surfaces. Since aluminum is a better heat conductor than steel, the claim is that this plan dissipates braking heat better than an all-steel rotor. On higher-end models, such as the RT-99, this is combined with Freeza engineering, where the aluminum core is besides formed into a fin heating system cesspool. Shimano claims them to be approximately 50 % more efficient at cooling than rotors with just Ice Tech .
Shimano IceTech
In the brake pads, Ice Tech refers to backing plates with built-in heat sinks. Like with the rotors, these help pull hotness away from the bracken pad and dissipate into the surrounding air. The disadvantage of the fin brake pads is marginally increase weight and monetary value .
While it may not be fitted on the bicycle you ’ ra buy, most of Shimano ’ s road-specific brakes are Ice Tech-compatible. Sometimes an upgrade in brake pads is all that ’ s required .
What is the difference between flat-mount and post-mount calipers? Are they compatible?
post mount brake example
Post-mount calipers were adopted from batch bikes in the early on days of road phonograph record brakes. here, the brake caliper ride onto thread posts on the frame, with the bolts running through the caliper. The arrangement allowed for easy repositioning and alteration of the caliper, deoxyadenosine monophosphate well as shared caliper bodies in the early days of road magnetic disk brakes .
Flat mount brake example
Flat-mount is a newer road-specific disc brake hop on, and is more compendious and lighter than post-mount. With flat-mount, the rear caliper affixed with two bolts running through a flatten frame surface and then threading directly into the caliper ( or adapter affixed to the caliper ). At the front, the caliper is first bolted to an adapter, which is then bolted to two string inserts on the branch .
Post-mount calipers can be installed for use on some flat-mount frames ; however, adapters for going the early way aren ’ deoxythymidine monophosphate generally available .
What is the standard rotor size?
This one is hush up to debate, and varies based on which manufacturer you ask. A larger-diameter rotor provide more leverage, and consequently increased braking world power, than a smaller matchless. additionally, a larger open area means better inflame management. On the flipside, smaller rotors are light, less likely to get damaged in a wreck, offer a more easy braking action, and are more aerodynamic .
Most companies, including SRAM and Campagnolo, suggest 160mm-diameter movement rotors on the road, as a conservatively safe option for managing heat on strain downhills. however, Shimano says that most riders will be fine on a 140mm-diameter front rotor thanks to the temperature-reducing Ice Tech technology .
There is a tendency, borrowed from mountain bikes and other disc-equipped vehicles, to mismatch rotor sizes on a motorcycle, since ampere much as 70 % of your braking power comes from the front wheel. An model of this is with the new Specialized Tarmac Sl6 Disc, where a larger 160mm rotor is featured up front man for increased brake power and heat control, with a lighter 140mm rotor at the back .
regardless of the argumentation, frames are typically optimised for a finical size. A bicycle like the Giant Propel Disc uses 140mm rotors, while others provide adaptors to size up .
What are two-piece rotors?
Let ’ s first base cover one-piece rotors. Most of these are stamped from a single piece of steel. many cheaper six-bolt rotors are one-piece .
two-piece rotors see the braking surface attached to a separate carrier or spider. This is often done to allow for a splined Center Lock attachment, but on higher-end models, it can besides reduce weight unit, increase rotor stiffness, and help with heat management, helping draw the heat away from the braking surface .
What’s the difference between metallic and organic pads?
An endless FAQ to road disc brakes
Both materials offer different characteristics, and your choice should depend on your riding style, discipline, location, and leaning for riding in foul weather .
Resin, otherwise known as organic, disk pads broadly offer better modulation and placid brake. Some brands, such as SRAM and Campagnolo, besides claim they dissipate heat better than metallic pads .
By contrast, metallic, besides known as sintered, pads are made of hard materials and have a higher metallic content than organic pads. As a leave, metallic pads offer greater crude stopping ability and last longer than organic pads, albeit at the expense of noisy run and fast rotor wear .
batch bikers have long had this choice, and the better lastingness means they much use sinter metallic pads. With less grit, less indigence for raw stopping power, and a demand for silent brake, the majority of disk users on the road prefer resin pads .
note : Some cheaper Shimano-equipped bikes come with “ Resin merely ” disk rotors, which are made of less-durable steel alloys. You ’ ll need better rotors if you decide to use metallic pads .
I see premium pads offered with aluminium or titanium; what’s the story?
This is all about system of weights savings. Disc-brake pad materials are normally bonded to sword backing plates, but ones made of aluminum or titanium will obviously save a few gram. broadly speaking, high-end resin pads will much use aluminum back plates, while the metallic versions will use titanium backing plate. Between the two, the aluminum ones are light .
This is not to be confused with Ice Tech finned pads, which are detailed above .
My bike looks like a bird’s nest. Can I trim the hydraulic brake hoses?
Shimano brake hose trim
Yep ! Being able to trim the bracken hoses is a feature of all systems on the market. however, it can be a more involved job .
At a minimal, you ’ ll need a way to trim the reinforced hosiery cleanly, and successor barb and olives to push into the fresh end of the hose. This is what creates the airtight sealing wax for wherever the hose is attached. While it is possible to cut most hoses without having to bleed the system, it ’ mho more likely a bleed will be needed .
Can I mix and match components between brands?
exchangeable to mixing and matching drivetrains, magnetic disk brake systems officially have very limited cross-compatibility, but there are some exceptions .
Cross-compatibility is one of the key benefits of mechanical disc-brake systems, and blend and matching different levers and calipers isn ’ deoxythymidine monophosphate equitable possible, it ’ randomness much baked into the purpose of the caliper. however, be mindful that not all brake levers pull the same come of cable for a given total of lever bowel movement, and certain combinations will work good than others. Shimano levers will broadly produce a firmer lever feel with more embroider clearance, but less ability, while SRAM and Campagnolo levers will typically yield excellent ability, but less pad headroom and a softer pry feel .
hydraulic systems are far more restrictive. Fluid capacity, brake fluid types, piston diameters, and hose fittings are enough cause to match the caliper manufacturer with the pry. There are some cases where you ’ re able to mix and match between different generations from within the same brand, but again, the manufacturers rarely suggest doing so .
Brake rotors are a different story, and while you ’ ll probably get the best performance by matching the rotor to the brake system ( specially with higher-end Shimano models ), mixing brands rarely results in any major issues .
Is there an easy way to swap between wheelsets on a disc-brake bike?
If the wheels you ’ re swapping between have the like hub, or possibly you ’ re lucky, there should be no remainder in rotor placement, and you ’ ll be all right to swap between wheels. But with so little clearance between the brake pads, and just adequate variability between different makes and models of hubs and wheels ( and sometimes even within the lapp name and model ), bracken rotors can often be placed in a unlike position relative to the dropout. If you only rarely swap wheels, then readjusting the caliper is the obvious answer. however, if you ’ re looking to swap regularly, then it ’ ll be worth spending the clock to set the wheels up indeed that all of the rotors are in precisely the same plane .
For where there is a difference in placement, the solution is rotor shims. A variety of brands ( e.g. Syntace ) produce shim kits for 6-bolt rotors while November Bicycle recently launched the foremost shim kit for Center Lock rotors. In both instances, all that is needed is to add a shim ( s ) to the wheel ( second ) where the rotor sits inboard until it no longer rubs on the inboard brake pad .

Road Disc Maintenance

How long do brake pads last for?
It depends. We ’ ve seen disc-brake pads disappear within a single wet farinaceous ride, and then other pads concluding two full seasons .
by and large speaking, if ridden in conditions where grit international relations and security network ’ t an topic, disc-brake pads will go further than rim-brake ones, particularly if you use metallic pads ( see the section about brake pad types above ). however, any sum of wet backbone will see the pads abrade aside decently quick .
How do I check for brake pad wear?
The brake diggings consists of the braking fabric and the backing plate. You can see how a lot embroider material is left by peering through the caliper. however, it may be necessity to take the roulette wheel out for a closer ocular inspection .
With Shimano pads, it ’ mho suggested that you replace your pads when there is less than 0.9mm of braking material impart. For SRAM, the minimal measurement is 2.5mm including the back pads. Campagnolo makes it easier with a wear furrow through the center of its pads ; substitute is required arsenic soon as the groove is no longer visible .
In addition, front for uneven wear on the slog surface or rotor, as this is typically a sign of a ailing adjusted brake .
And some brake pads are designed to make make noise once they ’ ra break. For exemplar, Shimano brake pads will begin to squeal when they have reached the recommend refilling charge .
Which brake pads do I need for my brakes?
An endless FAQ to road disc brakes
Disc-brake pads vary greatly based on the brand and model of bracken. It ’ s extremely important to match the pad with the brake caliper model.

once you ’ ve done this, you ’ ll find a count of third-party brands offering aftermarket pads. Some do it to be a cheaper option than original manufacturer pads. Others do it claiming superior performance, longevity, and randomness reduction ( such as SwissStop and KoolStop ) .
If you want to play it dependable, it ’ randomness broadly recommended to stick with the authentic stigmatize of disk pads ( rim brakes are a unlike story ) to match your caliper. It ’ s what your brakes were engineered to use, and honestly, I ’ ve had excessively many mix experiences to suggest otherwise .
What’s the difference between Shimano brake pad models?
The first letter in Shimano ’ s brake pad naming designates the pad shape and fitment. Certain brake calipers call for certain pads, and thus if you ’ ra diffident, match the model diagnose found on your caliper to the suggest list from Shimano. Shimano Dura-Ace, R9100, Ultegra R8000 and 105 R7000 disk calipers use an L-series pad. previous generation R785 calipers use a J-series diggings, which is the lapp as many previous generation mountain bike calipers .
The letter at the conclusion of the brake pad model name designates the back plate material. For example, “ A ” is for alloy ( aluminum ), “ S ” is for steel, “ Ti ” is for titanium and “ C ” is for cooling ( typically sword backing plate with alloy cooling fins ) .
If you ’ re shop for fresh resin disc brake pads to suit your newer Shimano road calipers, you may notice a choice between J02A, J03A, or L02A and L03A. The “ 02 ” are the previous interpretation resin slog, nowadays superseded by the 03 which call to offer 50 % better lastingness without giving up anything else. If given the choice, pick the newer “ 03 ” option .
Is it really that important to keep oils away from my disc-brake pads?
Yep. Disc brakes are allergic to any form of contamination. evening the anoint on your fingertips can be enough to upset the brake performance. Car brakes are arguably no different, but they offer far more surface sphere, and a far higher heating system that burns away such issues .
An endless FAQ to road disc brakes
Keeping your disk perfectly clear of any form of petroleum contaminant is the key to happiness. This means not using spray lubes on your chain, and besides being careful when washing your motorcycle in terms of the methods and detergents used. If you insist on spraying degreaser everywhere, don ’ thyroxine put it on the disk, and better even, use a clean and jerk deep-freeze bag ( held with an elastic band ) to cover the brake caliper .
How do I clean my disc brakes?
You shouldn ’ t need to, although possibly the occasional wiping away of brake dust with a clean and lint-free rag will be needed. A drip of water can be good, excessively .
Isopropyl alcohol
If you do need to clean them, use isopropyl alcohol, and preferably the 100 % kind, not the slightly diluted stuff you normally find in pharmacies. Yep, it ’ s not that bum, nor easy to find, but it ’ mho guaranteed to clean the brake surfaces without leaving any oily residue or causing cachet damage .
Automotive disk bracken cleaners can often be baffling. Some leave an buttery remainder, while others strip life out of condom seals. And fair about all degreasers will cause more damage than good .
Bicycle-specific disc-brake cleaners are more likely to be fine to use, but unfortunately, it ’ s not constantly the case. Some are precisely rebadged automotive cleaners, while others are just isopropyl alcohol at a higher monetary value. They ’ rhenium credibly fine, but then again, isopropyl alcohol is hush the recommended cleaner by all major disc brake manufacturers .
What is brake bed-in and why is it needed?
Brake bed-in, or burn-in, is the march of transferring launching pad material to the brake surface for proper affair. It ’ s a all-important dance step any time new brake pads or brake rotors are involved. Read our brake bed-in article for more on this subject .
How do I know when my brakes need to be bled?
SRAM brake bleed
Spongy-feeling levers or inconsistent brake feel are both sure-tell signs your brakes could use a bleed. Both of these symptoms are the leave of air in the system, which can sometimes happen if you let your brake pads wear besides far .
One comfortable way to check for this is to tip the bicycle top down while repeatedly squeezing the brake lever. Does it change the find ? Did the pry just pull to the legal profession ? If sol, you ’ ve got air in the system and need a bleed. If it feels precisely the like, you ’ re finely .
Another reason for re-bleeding is degradation of the fluid, frequently caused by excessive heat. Downhill mountain bikers know this excessively well, with brakes changing feel after extended downhills where rotors become red hot ( where ’ d you be risking blowing a sur with rim brakes ). Another rationality is that DOT fluid, such as that used in SRAM systems, absorb body of water over time, which finally lowers the boiling luff of the fluid .
Whatever the reason, a organization bleed will flush out the old fluid and vomit air out from the caliper, hose, and pry. Most brake manufacturers recommend this to be done per annum, but we know plenty of people who ignore this without publish .
What fluid can I use?
only use the fluent that your specific brake recommends. Shimano, Campagnolo, Magura, and a few others use specific types of mineral oil. SRAM brakes use automotive DOT 5.1 fluid .
mineral oil and DOT fluid are not cross-compatible, and using the ill-timed fluid will cause seals to swell and the brakes to fail. This is surely something to be very careful with, and be sure to not cross-contaminate systems by sharing bleed kits .
How do I bleed my brakes?
Shimano brake bleed
The march will vary depending on the bracken exemplary. The pursue links should help. Generally speaking, bleeding brakes involves a few brand-specific attachments, some basic tools, the right fluid, and a few syringes. Bleed kits are available from each mark ampere well as aftermarket suppliers, which offer a one-stop-shop option .
Why are my rotors a weird colour?
Assuming they ’ ra not just dirty, a change of color is a signal of heat price. Heat-damaged rotors will range in tinge from a picket scandalmongering, benighted yellow, to a increasingly dark colour based on the damage, moving into brown, empurpled, or even blue if sincerely roasted. If your rotors progress past yellow, you should look at ways to better manage the hotness ( such as using IceTech pads for Shimano systems and/or running larger rotors ) .
Do brake rotors wear out?
Disc brake rotors
Yep. Look closely at a Shimano rotor and you ’ ll see “ 1.5mm ” stamped on it. This is the minimum recommended thickness prior to replacement. Most brands hover around this crisscross. For case, SRAM suggests 1.55mm minimal thickness for its rotors .
The good news program is that the stainless steel steel braking surface of disk rotors is inherently durable, and you ’ ll likely go through many sets of disk pads anterior to needing new rotors. And when you do, just be felicitous it ’ second not your rims that are needing substitute .

Traveling with disc brakes

I heard I need to be careful when removing a disc-brake wheel; why?
This alone applies to hydraulic systems. It ’ s ascribable to the self-adjusting nature of the hydraulic systems, where the pistons are designed to push out until they contact an real property object ( the disk rotor ) and then retract a certain come .
If you squeeze the brake lever without a rotor in stead, the pistons will be pushed out until the two pads contact each early. It ’ s not the end of the universe if that happens, though ; in most cases, you ’ ll just need to reset the pads by pushing them back into the caliper body with a brake launching pad wedge ( or a clean flat sword screwdriver and a batch of care ) .
however, if your pads are sternly wear, it ’ s possible that you could push the pistons out back the seals, in which case you ’ ll vomit fluid everywhere and unseat the pistons. badly, this is bad newsworthiness .
If you do need to take a roulette wheel out for travel, either be careful to not touch the pry, or use a pad spacer/travel wedge. These are formative wedges supplied with every bicycle and brakeset ( your patronize should have some spare, if they didn ’ thymine give you some already ). They just clip into the brake caliper for travel and prevent the pads from being pushed together. Always ensure they ’ rhenium indisputable they ’ re clean prior to using them .
Is the brake fluid an issue when traveling?
Nope. It ’ s a non-pressurized varnish arrangement, and the relatively minor changes in atmospheric coerce associated with atmosphere locomotion are no big deal .
I was told not to turn a disc brake bike upside down? Is it true?
It ’ second largely a myth, but with rationality .
The earliest disc-brake systems on mountain bikes could suck tune into the hoses if the bicycle was turned top down. however, none of the newer bracken systems on the grocery store use this design, and in hypothesis, there ’ s no air that can migrate into the lines .
however, modern brakes that are improperly bled can leave air trapped in the fluid reservoir at the lever, which will entirely present itself when the bicycle is inverted. If you have a bicycle with mod phonograph record brakes and the levers go piano when the motorcycle is flipped top down, that ’ s a good sign you ’ re due for a shed blood .
What can I use to protect the disc rotors in a travel case?
lightweight cassette tools
Disc rotor protectors do exist, and many disc-equipped bikes are shipped with such things. Ask your local shop for some, assuming they ’ ve haven ’ deoxythymidine monophosphate made it to the bin however. however, these will alone do so a lot, and then my advice is to remove your rotors for travel .
Removing your brake rotors is easy with Center Lock rotors, and there are evening lightweight tools designed specifically for this, such as the Wolf Tooth Components Pack Tool scope. Six-bolt rotors are still easy enough to work with, but far slower and fiddly .
once removed, store the rotors in clean resealable plastic bags. This will ensure the rotors don ’ deoxythymidine monophosphate catch contaminated by touching anything else in your sheath .

Troubleshooting

Why do my brakes squeal?
More much than not, this is ascribable to contaminant. Sometimes it ’ mho poor frame-up, sometimes it ’ s a warn of needing new pads, sometimes it ’ randomness because your pads are glazed or of the wrong fabric, but about always, it ’ randomness contamination .
Keeping any shape of oil, degreasers, and motorcycle cleaners away from your disc brake pads and rotors is a sure means to keep them squeak-free. And of course, a proper bed-in process is a must, excessively .
Why do I occasionally hear brake rub at random times?
Discs brakes run on very tight tolerances, with typically only a millimeter or less of space between the rotor and the pads. This doesn ’ t leave a lot room for error. If your brakes make rubbing noises at random times, it ’ s either a sign of the zodiac of flex, a brake needing service, or outside elements .
Hub and frame/fork/axle flex can be the campaign of the rub. Do you only always hear it when leaning the bicycle over in a particular direction or in a sprint ? If thus, it ’ s flex. Checking that your axles are done up close is the first footfall. besides check that there ’ mho no play in your hubs while you ’ re at it. If that doesn ’ t take concern of the offspring, check that the caliper is by rights positioned with an even gap to the pads on both sides of the rotor. If that doesn ’ t fix it, it may be fair be a flexy axle or dropout setup .
sometimes pads rub because the pistons behind them are getting gluey. This can be due to a build-up of debris, or sometimes fair with long-run use. But a brake overhaul ( where the pistons are reset and cleaned ) and the brake bleed will normally solve the problem .
last, mud, grit, or precisely homely water can be enough to make sounds on your disk. If you barely rode through a addle and now they ’ re rub, don ’ t stress about it. Applying your brakes will probably clear the muck and bring back the silence .
My brakes rub, but only at one point of the wheel. What do I do?
Shimano disc rotor
Sounds like you ’ ve got a warped disk rotor. They ’ re only approximately two millimeters thick, so it ’ sulfur expected that they can bend. Because of this, it does pay to be careful : don ’ thyroxine lean the motorcycle up against the rotor, and take extra care when transporting the bicycle in a vehicle or case to keep the rotors from being damaged .
If this has happened directly following a long descent, it may be estrus related. Give the rotor time to cool, and if placid warped, continue with the advice below .
If the rotors are not terribly flex, they can be pulled or pushed back into shape. This is typically done with the wheel in the bicycle, using the brake pads as a gauge. Use a part of clean newspaper towel to touch the phonograph record airfoil with, and lightly use your finger at the point of rubbing to push the rotor in the diametric guidance. Go easy ; it doesn ’ t take much force to bend the rotor second .
For a little more preciseness, just about every creature sword offers a specific tool for this job. alternatively, you can use an adjustable wrench, but fair make certain it ’ mho extremely clean before you do .
My hydraulic brakes constantly rub; what can I do?
Did you just have the wheel out and now they ’ rhenium rubbing like crazy ? If indeed, refer to our section above about traveling with disk. The solution here is to push the bracken pads ( and pistons ) back into the caliper to reset the system .
If this wasn ’ t the case, you ’ ve probable got a bracken caliper that needs aligning. Peer through the caliper and see whether the rotor is rubbing on one specific side. Yes ? Ok, it ’ south time to slenderly loosen the two bolts holding the caliper in position. once at large, many calipers will mechanically centre by pulling the brake lever and then tightening the two bolts while holding the lever. sometimes this doesn ’ t employment, but there are enough of other tricks to overcome this. Sighting through the caliper and cautiously tightening the caliper may work ( with a white nibble of paper on the labor, to making visibility easier ) .
Another option is to use a business card between the rotor and pad that is rubbing. With the business tease in place, repeat the action above. Loosen the caliper bolts, squeeze the lever, and tighten the bolts while holding the lever. This may take some trial and error, but it ’ ll typically fix the write out when the brakes are not mechanically positioning themselves correctly .
If you ’ ve precisely installed new pads, and now the gap is minimal, try pushing the pistons back into the bores of the caliper ( use a fictile tire pry, or a the ring-end of a little wrench ). sometimes your brake system will have besides much fluid in it, which can occur if your brakes were given a quick bleed or top-up with wear pads in space. A clean bleed, or carefully opening the system to release fluid ( without letting tune in ! ) will be required .
I’ve had a few people attempt to adjust my brakes, but no matter what, the pads are not contacting the rotor square. What now?
Assuming the caliper adaptation is proper, and your rotor is directly, then it sounds like your frame/fork mount is to blame. Speak to your frame manufacturer about a solution, but most likely they ’ ll suggest getting the inning surfaces faced ( and hopefully, they ’ ll foot the bill ) .
Park Tool Disc tab facing tool DT-5.2
Park Tool makes a instrument called the DT-5.2 Disc Tab Facing Tool for this very issue. sometimes paint, or just bum manufacture tolerances, can cause alignment issues. The phonograph record tab key facing tool will remove fabric until the brake caliper mounting surface is analogue to the axle. It ’ s an highly expensive cock, sol attend for a workshop that has one ( and unfortunately, few of them do ) .
My spinning disc brake cut off my left leg. What do I do?
Bugger. Are you sure it wasn ’ t the race fencing ? actually, it was credibly the chain closed chain. Either way, you should probably seek medical attention .
My disc brakes lack power. What can I do?
A few things could be causing this, but most likely, it ’ randomness one of the succeed issues .
first, it ’ s most likely your braking airfoil is contaminated. Any measure of oil, flush that of your body oil from your fingertips, can upset the performance of magnetic disk brakes. Cleaning the system may help, but if it ’ south ill contaminated, new pads and a thoroughly cleaned rotor are likely the best answer .
Another campaign can be from an faulty bed-in work, causing glaze or exchangeable on the pads and rotors. See our article about brake bed-in to learn more .
Speaking of glaze, it ’ s potential for this to happen if the brakes are dragged on an extremely hanker descent. This can be identified with a glass-like finish to your brake pad surfaces. Remove the pads and rub them along some clean sandpaper ; that should do it .
It may besides be publicize in your system that ’ randomness preventing power from being transferred efficiently fro the lever to the caliper. A brake bleed will solve this ; see our section about brake shed blood above .
last, it may be that your brake rotors aren ’ t big enough for your riding style or body burden, specially if your bicycle is presently equipped with 140mm-diameter rotors. Speak to your workshop about whether your bicycle can support moving to a larger rotor that will offer greater leverage .
What can I do if my hydraulic brake lever pulls very close to the bar?
Sounds like there ’ s not enough fluid in the system. Check whether a bleed is needed by following the recommendation in the “ How do I know when my brakes need bleeding ? ” department above .
If that ’ s not the cause, then this is known as lever stroke. You have a few early options .
Pumping the brake pads to run closer to the rotor will provide less lever travel. To do this, remove the wheel ( and rotor ) and cautiously wrench brake until you see the pads move. Re-install the wheel and check lever feel. Repeat this process until the lever is american samoa desired. Do be warned that doing this will make it harder to get a rub-free apparatus, and it ’ ll only last until the pads wear .
Some brakes besides offer lever stroke adjustment. If this is an available option, there ’ s likely a adjustment screw that can be used to reduce the pry throw .
Why do my brakes lose power when braking for long periods?
This is known as brake fade. It ’ randomness sometimes a bless that the brake fluid is getting besides hot, and is starting to boil. When that happens, the once-incompressible fluid becomes a compressible gas, and you ’ ll promptly misplace power. If this occurs, it ’ mho powerfully recommended that you move to a larger rotor size, or if available, heat-dissipating brake pads and rotors, such as Shimano ’ second Ice Tech range .
alternatively, it may be a bless that you have air in your arrangement. See the section above on bleeding brakes .
What do I do if my brakes suddenly lose power?
well that ’ s not commodity !
The beginning thing to do is to try and pump the brake. This is simply a matter of squeezing the lever cursorily on and off. If it ’ second breeze causing your sudden brake woes, then pumping the lever will hopefully move the bubble out of the hose and up into the reservoir .
If that doesn ’ thyroxine ferment, then most likely you ’ ll be left with one good brake. Use it carefully to come to a stop and then proceed with absolute caution. Speak to your local anesthetic patronize about the issue and have them check the system. Although highly rare, a faulty part is a likely perpetrator of a broad bankruptcy.

What did we miss ? What are your top tips when it comes to disc brakes ?
Disc brakes are a technical product and require a commodity come of cognition and ability to be serviced. With any of the tips above, be certain to consult with a professional if at any decimal point you ’ re uncertain. Functioning brakes do topic .

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Category : Car Brakes