| Early bicycles such as the high wheeled | | | | generally require less finger effort to |
| penny-farthing bikes had no brakes as we | | | | achieve the same braking power. The |
| would recognize them today. As the machines | | | | disadvantages are that they are usually |
| were fixed gear bicycles a rider could reduce | | | | heavier and more expensive than rim brakes, |
| speed by reversing the thrust on the pedals. | | | | and require a hub built to accept the disc |
| Otherwise, a rider who wanted to stop quickly | | | | and a bicycle frame or fork built to accept |
| had to jump off the bike as it was moving. | | | | the caliper. Also, rigid forks on road bikes |
| Unsurprisingly there were many accidents, | | | | and tandems that are made to handle the |
| some of them fatal, which limited the appeal | | | | forces of a front disc brake are heavier and |
| of cycling mostly to young and adventurous | | | | may not have the ride quality of a regular |
| men. | | | | fork. Furthermore, a disc brake puts more |
| | | | stress on a wheel's spokes than a rim brake, |
| The 1870s saw the development of the "safety | | | | since the torque of braking occurs between |
| bicycle" which was roughly the bicycle we | | | | the hub and the rim with disc brakes, unlike |
| would recognize today, with two wheels of | | | | with rim brakes. For this reason, |
| equal size, initially with solid rubber | | | | cross-lacing of spokes is usually employed |
| tires. These were generally equipped with a | | | | with disc brakes, while rim brakes sometimes |
| front spoon brake and no rear brake, although | | | | allow the option of lighter radial lacing. |
| with no free wheel, back-pedalling was an | | | | |
| option. This was undoubtedly a big | | | | There are two general categories of disc |
| improvement on having no brakes at all, but | | | | brakes, mechanical and hydraulic. Mechanical |
| it was not very powerful and almost useless | | | | disc brakes (which are almost always less |
| in wet weather. | | | | expensive than hydraulic) use regular brake |
| | | | cables and levers to actuate the pads. |
| With the introduction of the pneumatic tire | | | | Hydraulic disc brakes use fluid from a |
| also came the next advance in bicycle braking | | | | resevoir, pushed through a hose, to actuate |
| around the 1890s, the invention of the rim | | | | the pistons in the disc caliper, that then |
| brake. This is the type of brake most | | | | actuate the pads. Hydraulic disc brakes |
| commonly used on bicycles today. Track | | | | occasionally require bleeding of the brake |
| bicycles, however, which are ridden at top | | | | lines to remove air bubbles. There are two |
| speed continuously, continue to be built with | | | | types of brake fluid used in disc brakes |
| no brakes; since they are fixed gear | | | | today: mineral oil and DOT fluid. Mineral oil |
| bicycles, braking on these bikes is still | | | | is generally inert and while DOT has a higher |
| achieved only by reversing the force on the | | | | boiling point, it is known to be corrosive to |
| pedals. This is not a disadvantage for the | | | | frame paint. The two are generally |
| very specialized manner in which these | | | | interchangeable as the different fluids may |
| bicycles are ridden. | | | | cause seals to swell or be corroded |
| | | | |
| Types of bicycle brakes | | | | Many disc brakes have their two pads actuated |
| | | | from both sides of the caliper, while some |
| Rim brakes | | | | (less expensive in both hydraulic and |
| | | | mechanical varieties) have only one pad that |
| There are several types of rim brakes. In all | | | | moves. Many hydraulic disc brakes have a |
| of these designs, the braking force is | | | | self-adjusting mechanism so as the brake pad |
| applied by the rider squeezing a lever | | | | wears, the pistons will keep the distance |
| mounted on the handlebar; this causes | | | | from the pad to the disc consistent in order |
| friction pads (usually made of leather or | | | | to maintain the same brake lever throw. |
| rubber) to contact the rim of the rotating | | | | Mechanical discs have a manual adjuster to |
| wheel, thus slowing it and the bicycle. | | | | dial in the pad to rotor distance. Calipers |
| | | | are now generally made in one piece to |
| Rod brakes use a series of rods and pivots | | | | increase stiffness and reduce the threat of |
| (rather than Bowden cables) to pull the | | | | leaks, although the two piece design still |
| friction pads upwards onto the inner surface | | | | reduces heat builup more effectively than the |
| (facing the hub) of the wheel rim. They were | | | | one piece, and most top end models still |
| often called "stirrup brakes" due to their | | | | feature the 2 piece caliper. |
| shape. In order to fit the rear wheel as well | | | | |
| as the more directly actuated front wheel, | | | | There are two standards for mounting disc |
| these brakes need a mechanism to transmit the | | | | brake calipers - IS (International Standard) |
| force but still allow rotation where the fork | | | | and post mount. IS is the more common of the |
| attaches to the frame. Although rod brakes | | | | two. Manitou is the inventor of post mount. |
| are heavy and the linkage is complex, they | | | | The advantage of post mounting is that it's |
| are reliable and durable and can be repaired | | | | easier to align the caliper to the rotor |
| or adjusted with simple hand tools in areas | | | | since there is some allowable side to side |
| where replacement Bowden cables are not | | | | adjustment. You must use spacers to properly |
| available or are too expensive. They are | | | | align IS calipers. The disadvantage to post |
| still used on some bicycles, typically | | | | mount is that the bolt is threaded directly |
| roadsters, particularly in the Far East. | | | | into the fork lowers. If the threading was |
| | | | stripped or if the bolt was stuck, then it |
| More modern designs use similar friction pads | | | | would require purchasing new fork lowers. |
| to squeeze the sides of the wheel rims, with | | | | Frame manufacturers have standardized the IS |
| the force transmitted to the brake from the | | | | mount for the rear disc brake mount. |
| lever by means of a Bowden cable. Designs | | | | |
| include the scissor-action "side pull" and | | | | There are two standards for disc hubs - IS |
| "centre pull" brakes, and the lever action | | | | and centerlock. IS is a six-bolt mount and is |
| "cantilever" and "V" brakes. | | | | the industry standard. Centerlock is patented |
| | | | by Shimano and uses a splined interface along |
| Single pivot side-pull caliper brakes are | | | | with a lockring to secure the disc. The |
| currently used on the most inexpensive bikes, | | | | advantages of centerlock are that the splined |
| before the introduction of dual-pivot caliper | | | | interface is stiffer, removing the disc is |
| brakes they were used on all types of road | | | | quicker because it only requires one lockring |
| bicycles. They consist of two curved arms | | | | to be removed, and the hubs and discs are |
| that cross at a pivot above the wheel and | | | | lighter than the 6 bolt ones. The |
| hold the brake pads on opposite sides of the | | | | disadvantage is that the design is patented |
| rim. These arms have extensions on one side; | | | | requiring a licensing fee from Shimano. |
| the cable housing is attached to one | | | | Advantages of IS six-bolt are that you have |
| extension and the inner cable to the other, | | | | more choices when it comes to hubs and |
| so that when the brake lever is squeezed, the | | | | rotors. IS rotors use allen bolts or Torx |
| arms move together and the brake pads squeeze | | | | bolts to secure them to the hub. This also |
| the rim. These brakes are simple and | | | | makes IS rotors harder to remove and the |
| effective when designed for relatively narrow | | | | possiblity of stripping the bolts and |
| tires, but have serious disadvantages if made | | | | requiring a new hub. |
| big enough to fit wide tires. The low quality | | | | |
| varieties also have a tendency to rotate to | | | | The rotors come in several different sizes, |
| one side during actuation and to stay there, | | | | generally six, seven, or eight in diameter. |
| so that one brake pad continually rubs the | | | | These are the industry standard sizes, some |
| rim even when the brake is released. | | | | prototype versions are coming out with 9 in |
| | | | diameter rotors now. As the rotor size |
| Center-pull caliper brakes in the past filled | | | | becomes bigger, so does the torque on the |
| the price niche between the cheaper and the | | | | wheel resulting in a more powerful brake. |
| more expensive models of side-pull brakes, | | | | Also for every revolution of the wheel more |
| being reasonably priced but without the | | | | area of the disc passes through the caliper |
| tendency of the cheaper sidepull brakes to | | | | making the bigger rotors run cooler. If too |
| have one brake pad continually rub the rim. | | | | small of a disc is run for your specific type |
| In this type of brake the actuation of the | | | | of riding, brake fade may be experienced |
| two brake arms is designed to be symmetrical. | | | | because of the brake fluid boiling. |
| The cable housing is attached to a fixed | | | | |
| cable stop attached to the frame, and the | | | | Drum brakes |
| inner cable attaches to a sliding piece or | | | | |
| sometimes a small pulley, over which runs a | | | | Drum brakes are used mainly on bicycles which |
| straddle cable which connects the two brake | | | | are operated in wet or dirty conditions. |
| arms. Thus tension on the cable is evenly | | | | Though heavier, more complicated, and |
| distributed to the two arms, preventing the | | | | frequently weaker than rim brakes, they |
| brake from taking a "set" to one side or the | | | | require much less maintenance and are less |
| other. | | | | affected by road conditions. Both cable- and |
| | | | rod-operated drum brake systems have been |
| Dual-pivot caliper brakes are used on most | | | | widely produced. While most common on utility |
| modern racing bicycles. The cable housing is | | | | bicycles in certain countries, especially the |
| attached like that of a side-pull brake. | | | | Netherlands, they are also frequently found |
| Centering of side-pull brakes was simplified | | | | on freight bicycles. |
| with the mass-market adoption of dual-pivot | | | | |
| side-pulls (an old design re-discovered by | | | | A bicycle drum brake's operation is identical |
| Shimano in the early 1990s). These brakes | | | | to that of a car's with the exception of the |
| also offer a higher mechanical advantage. | | | | absence of a ratching adjustment mechanism |
| Dual-pivot brakes have slightly higher weight | | | | and hydraulic actuation. Two pads are pressed |
| than conventional side-pull calipers and | | | | outward against the braking surface on the |
| cannot accurately track an out-of-true rim. | | | | inside of the hub's shell, which is packed |
| One arm pivots at the center, like a | | | | with grease. Shell diameters on a bicycle |
| side-pull; and the other pivots at the side, | | | | drum brake are typically 70 - 120 mm. Drum |
| like a center-pull. | | | | brakes have been used on front hubs and hubs |
| | | | with both internal and external freewheels. |
| Cantilever, direct-pull, and V-brakes have | | | | |
| each arm attached to a separate pivot point | | | | A common design of drum brake is the Roller |
| on one side of the seat stay or fork just | | | | Brake, manufactured by Shimano. This is a |
| below the rim. The wider tires on mountain | | | | modular cable-operated drum brake for use on |
| bikes present a problem with standard | | | | specially splined front and rear hubs. Unlike |
| calipers because the long distance from the | | | | a normal drum brake, the Roller Brake can be |
| pivot to the pad allows the arms to flex, | | | | removed entirely from a hub, allowing it to |
| reducing braking effectiveness. Cantilever | | | | function as a regular freewheel. It also |
| brakes are one solution to this problem. | | | | contains a torque limiting device which |
| | | | reduces its effectiveness on bicycles with |
| The traditional cantilever has an L-shaped | | | | adult-sized wheels. |
| arm protruding outwards on each side, with a | | | | |
| cable stop on the frame or fork to hold the | | | | Drag brake |
| cable housing and a straddle cable between | | | | |
| the arms similar to the centerpull brake. The | | | | In addition, drum brakes are also installed |
| cable from the brake handle pulls upwards on | | | | on some tandems used in mountainous areas as |
| the straddle cable, causing the brake arms to | | | | a so called drag brake. In this application, |
| rotate up and inward and squeezing the rim | | | | the drum is not intended to stop the bike |
| between the brake pads. | | | | but, rather, to keep the speed down on long |
| | | | downhill sections where extended use of rim |
| V-brakes (sometimes called linear- or | | | | brakes can cause the tire to become hot |
| direct-pull) mount similarly, but the arms | | | | enough to explode. |
| extend straight up, and the outer housing is | | | | |
| attached to one arm and the inner housing to | | | | The largest manufacturer of this type is |
| the other, similar to the cable attachment | | | | Arai, whose brakes are screwed onto hubs with |
| for sidepull brakes. They are generally more | | | | conventional freewheel threading on the left |
| powerful and easier to adjust than cantilever | | | | side of the rear hub and operated via Bowden |
| brakes, and have the additional advantage of | | | | cables. |
| functioning well with the suspension systems | | | | |
| found on many mountain bikes because they are | | | | Coaster brakes |
| self contained and do not require a separate | | | | |
| cable stop. However due to their higher | | | | A coaster brake, also known as a back pedal |
| mechanical advantage, the brake pads must be | | | | brake or foot brake (or torpedo in some |
| positioned very close to the rim. Also see | | | | countries), is a drum brake integrated into |
| V-brake adjustment. | | | | hubs with an internal freewheel. Freewheeling |
| | | | functions as with other systems, but, when |
| Closely related is the U-brake; this type has | | | | back pedalled, the brake engages after a |
| the pivots for the arms mounted to the frame | | | | fraction of a revolution. It can frequently |
| or fork on each side above the rim. The arms | | | | be found in both single-speed and geared |
| cross over similarly to sidepull or | | | | hubs. |
| centerpull brakes, and BMX bikes; its main | | | | |
| advantage was that it did not protrude | | | | When such a hub is pedalled forwards, the |
| sideways from the frame like the early | | | | sprocket drives a screw which forces a clutch |
| cantilevers. This advantage was reduced by | | | | to move along the axle, driving the hub shell |
| redesigned low-profile cantilevers, and | | | | or gear assembly. When pedalling is reversed, |
| nearly eliminated with V brakes. | | | | the screw drives the clutch in the opposite |
| | | | direction, forcing it either between two |
| One of the least common rim brakes is the | | | | brake pads and pressing them against the |
| hydraulic rim brake. These brakes are | | | | shell, or into a split collar and expanding |
| generally able to be mounted on the same | | | | it against the shell. The braking surface is |
| pivot points used for cantilever and | | | | often steel, and the braking element brass or |
| linear-pull brakes. They were available on | | | | phosphor-bronze, as in the UK Birmingham made |
| some high-end mountain bikes in the early | | | | Perry Coaster Hub. |
| 1990's, but declined in popularity with the | | | | |
| rise of disk and linear-pull brakes. The | | | | Coaster brake bicycles are generally equipped |
| moderate performance advantage (greater power | | | | with a single cog and chainwheel and use a 1" |
| and control) they offer over the latter is | | | | chain. However, there have been several |
| offset by their greater weight and | | | | models of coaster brake hubs with derailleurs |
| complexity. The only significant current use | | | | in the past, most notably the Sachs 2x3. |
| of these brakes is on bicycles used for | | | | These use special extra-short derailleurs |
| trials riding. | | | | which both can stand up to the rigors of |
| | | | being straighted out frequently and don't |
| Another design is the delta brake. In this | | | | require an excessive amount of reverse pedal |
| design, the pivot points for the arms are | | | | rotation before the brake engages. |
| above the rim but the arms do not cross over, | | | | |
| and instead of a straddle cable, the inner | | | | Although coaster brakes have the advantage of |
| brake cable attaches to a wedge shaped piece | | | | being protected from the elements and thus |
| between the brake arms; when the brakes are | | | | immune to ice or water, because they are |
| applied the wedge forces the arms apart at | | | | located in the rear wheel only limited |
| the top, squeezing the rim between the pads. | | | | braking force can be applied before the rear |
| This has an advantage in that the shape of | | | | wheel locks up. This is due to the placement |
| the wedge can be varied other than | | | | of the rider's weight ahead of the rear |
| straight-sided, to allow for a very high | | | | tyre's contact with the ground, as well as |
| mechanical advantage at the point where the | | | | the weight transfer forward proportional to |
| pads contact the rim to give high braking | | | | braking force, which further unloads the rear |
| power, but a lower mechanical advantage when | | | | wheel. Additionally, although coaster brakes |
| the pads are not contacting the rim so that | | | | generally go years without needing |
| the pads move well away from the rim when the | | | | maintenance, they are more complicated than |
| brake is not applied, preventing any rubbing. | | | | rim brakes to repair if it becomes necessary. |
| | | | |
| The advantages of rim brakes are that they | | | | Spoon brakes |
| are inexpensive, lightweight, mechanically | | | | |
| simple, and easy to maintain, as well as very | | | | The spoon brake was one of the first types of |
| powerful. The main disadvantage of rim brakes | | | | bicycle brakes and precedes the pneumatic |
| is that their performance deteriorates in wet | | | | tire. They were first used on penny farthings |
| weather when the rims are wet. This problem | | | | with solid rubber tires in the late 1800's |
| is less serious on more expensive bikes which | | | | and continued to be used after the |
| use rims made of aluminum alloys than on | | | | introduction of the pneumatic tired safety |
| those with steel rims. They are also prone to | | | | bicycle. It consists of a pad (often leather) |
| clogging with mud, particularly when mountain | | | | which is pressed onto the top of the front |
| biking. Rim brakes also need regular | | | | tire. These were almost always rod-operated |
| maintenance. Brake pads wear down quickly, | | | | by a right-hand lever. In developing |
| and have to be replaced. Over long periods of | | | | countries, a foot-operated form of the spoon |
| time and use, rims also become worn. Bowden | | | | brake is sometimes retrofitted to old rod |
| cables can jam if not regularly lubricated or | | | | brake roadsters. It consists of a |
| if water gets into the housing, causing | | | | spring-loaded flap attached to the back of |
| corrosion. The cables also wear, requiring | | | | the fork crown. This is depressed against the |
| frequent checking and replacement. If the | | | | front tire by the rider's foot. |
| inner cables are not replaced when they fray, | | | | |
| they will suddenly break when brakes are | | | | Perhaps more so than any other form of |
| applied strongly, causing brakes to be lost | | | | bicycle brake, the spoon brake is very |
| precisely when they are most needed. Rim | | | | sensitive to road conditions and increases |
| brakes also require that the rim be | | | | tire wear dramatically. |
| relatively true; if the rim has a pronounced | | | | |
| wobble, either side to side or inwards and | | | | Though made obsolete by the introduction of |
| outwards, it will be impossible to adjust the | | | | the coaster brake and rod brake, they |
| brake pads so that they can apply sufficient | | | | continued to be used supplementally on adult |
| pressure to the rim but do not rub when | | | | bicycles until the 1930's and children's |
| released and do not contact the tire, which | | | | bicycles until the 1950's, in the West. In |
| would lead to a rapid blowout. | | | | the developing world, they were manufactured |
| | | | until much more recently. |
| Rim brakes also suffer from the disadvantage | | | | |
| of rim heating, because the brake converts | | | | Braking technique |
| kinetic energy into heat, which increases the | | | | |
| temperature of the rim (the brake caliper and | | | | Effective use of a bicycle brake is highly |
| frame do not become hot because brake pads | | | | counter-intuitive. The casual rider will at |
| are excellent thermal insulators). In normal | | | | first avoid using the front brake, due to the |
| use and with lightweight bicycles this does | | | | unsettling feeling of "toppling up", or fear |
| not present a problem as the brakes are only | | | | of being sent flying over the handlebars. |
| applied with a limited force and for a short | | | | |
| time, with the heat being quickly disspated | | | | However, the most effective technique for |
| to the surrounding air. However, on | | | | powerful stopping is to use the front brake |
| heavily-laden touring bikes and tandems in | | | | almost exclusively. There are several |
| mountainous regions the heat build-up can be | | | | exceptions where the rear brake is preferred; |
| sufficient to increase tire pressure to the | | | | these are listed below. In any stop, the |
| extent that the tire blows off the rim. If | | | | rider should shift their weight toward the |
| this happens on the front wheel a serious | | | | rear and use their arms to brace against the |
| accident is almost inevitable. The problem is | | | | deceleration. |
| worse when descending cautiously at slow | | | | |
| speeds because the brakes are "always on" and | | | | During braking (either with the front or rear |
| the cooling airflow over the rim is | | | | brake), the bike deceleration causes a |
| insufficient. The risk can be minimised by | | | | transfer of weight to the front wheel. This |
| not over-inflating tires and the adoption of | | | | means that there is more force pressing the |
| an aggressive riding style, only braking for | | | | front wheel to the ground, and the back wheel |
| the corners, but the real solution is a hub | | | | nearly none. Therefore, the front wheel can |
| brake or a disc brake which allows the rim to | | | | generate more frictional braking force than |
| remain cool. | | | | the back wheel before locking up and |
| | | | skidding. In any conditions and especially in |
| Brake pads (brake blocks) are of many | | | | wet conditions or going downhill, the rear |
| designs. Most consist of a replaceable rubber | | | | brake can exert relatively little braking |
| pad held in a metal channel (brake shoe), | | | | force before the wheel locks and starts |
| with a post or bolt protruding from the back | | | | skidding. For a more-detailed analysis, see |
| to allow attachment to the brake, but some | | | | Bicycle and motorcycle dynamics. |
| are made as one piece with the attachment | | | | |
| directly moulded in the pad for lower | | | | A skidding rear wheel can lead to dangerous, |
| production costs. The rubber can be softer | | | | uncontrollable bicycle movements eventually |
| for more braking force with less lever | | | | resulting in the cyclist falling on the |
| effort, or harder for longer life. The rubber | | | | ground. A key scenario for this is "light" |
| can also contain abrasives for better | | | | braking on rapid alpine-type hairpin |
| braking, at the expense of rim wear. | | | | (serpentine) descents; further attenuation of |
| Compounds vie for better wet braking | | | | speed to negotiate a decrease in curve radius |
| efficiency. Typically pads are relatively | | | | (tightening of the bend in the road) can be |
| short, but longer varieties are also | | | | executed successfully while pulling through a |
| manufactured to provide more surface area for | | | | tight corner regulating with the front brake |
| braking; these often must be curved to match | | | | only. |
| the rim. It should be noted that a larger pad | | | | |
| does not give more friction, but it does wear | | | | In an emergency stop, it is important to grab |
| more slowly and therefore a new pad can be | | | | the front brake and press it hard to stop in |
| made thinner, simplifying wheel removal with | | | | the minimum possible distance. The rider |
| V-brakes in particular. In general, a brake | | | | should shift his or her weight as far to the |
| can be fitted with any of these many | | | | rear as possible to avoid flipping over the |
| varieties of pads, so long as the pad | | | | handlebars. Maximum deceleration is |
| mounting method is compatible. Carbon rims, | | | | accomplished by maintaining enough pressure |
| as on some disc wheels, generally have to use | | | | on the front brake such that that the rear |
| non-abrasive cork pads. | | | | wheel is barely touching the ground, just |
| | | | before lifting up. In reality this is not |
| Disc brakes | | | | practical for most cyclists. Instead, use |
| | | | light pressure on the back wheel and hard |
| Disc brakes consist of a metal disc attached | | | | pressure on the front. The back wheel is |
| to the wheel hub that rotates with the wheel. | | | | primarily useful as an indicator—when |
| Calipers are attached to the frame or fork | | | | it starts to skid, reduce the pressure to |
| along with pads that squeeze together on the | | | | both brakes to prevent the rear wheel from |
| disc. Although these brake types have been | | | | lifting, then increase pressure to both |
| successfully used on, and have been the | | | | again. |
| principal choice for motorbikes for decades, | | | | |
| numerous (partly successful) attempts at | | | | Incidentally, on tandems, and long-wheel-base |
| introducing disc brakes for bicycles over the | | | | recumbents with their long wheelbase and |
| last decades [citation needed] may now | | | | center of mass farther from the front wheel, |
| finally have reached fruition. Recent weight | | | | it is virtually impossible for heavy front |
| costs/reliability material advances have led | | | | braking to cause the machine to flip. |
| to development and implementation of disc | | | | |
| brake systems by several firms to the extent | | | | There are a few special situations where |
| that they are becoming a standard feature on | | | | limited use of the front brake, and heavier |
| many bicycles, and are almost certainly here | | | | involvement of the rear brake is advisable: |
| to stay. Disc brakes are most suitable for | | | | |
| and used mainly on mountain bikes ridden | | | | Slippery surfaces: It is difficult to recover |
| off-road. They also are used on hybrid | | | | from a front-wheel skid on a slippery |
| bicycles and some road bicycles, although | | | | surface, especially when leaned over, so on |
| this is less common. Many tandem bicycles | | | | surfaces when skidding is likely (e.g. wet |
| have a disc brake fitted on the rear wheel in | | | | pavement, mud, snow, or ice), reduced speed |
| addition to rim brakes; the disc brake can be | | | | and use of the rear brake may be preferred. |
| set to provide a constant drag, so that | | | | |
| during long descents, the rim brakes are not | | | | Bumpy surfaces: If the front wheel comes off |
| overworked by the heavier machine.[citation | | | | of the ground during braking, it will stop |
| needed] | | | | completely. Landing on a stopped front wheel |
| | | | with the brakes still applied is likely to |
| The main advantage of disc brakes is that | | | | cause the front wheel to skid and, possibly, |
| their performance is equally good in all | | | | for the rider to flip over the front bars. |
| conditions including water and mud. They also | | | | |
| avoid the problem that rim brakes have of | | | | Flat front tire: Braking the front wheel when |
| wearing out the wheel rims, especially in | | | | the tire is flat could cause the tire to come |
| muddy conditions, as well as the requirement | | | | off of the rim, which is more likely to cause |
| that the rim be true. Also, disc brakes offer | | | | a crash. |
| better modulation of braking power and | | | | |