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Adjusting Direct-pull Cantilever Bicycle Brakes ("V-Brakes ®")
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by Sheldon "Direct Pull" Brown
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vbrake

About Rim Brakes

Direct-pull brakes are a type of cantilever rim brake. In connection with this article, please read the lead article about rim brakes. It covers, among other things,

Most brake problems result from excessive friction or poor installation of the cables, not poor setup, or poor quality brakes. Also see the article on cables for information on cable selection and adjustment of brake cables and brake levers.

Direct-pull vs Traditional Cantilever Brakes

Traditional cantilever brakes used two cables, a main cable running down the centerline of the bike, and a second, "transverse" cable connecting the cantilever units on each side of the wheel. The main cable would pull upward on the middle of the transverse cable, causing the cantilever units to rotate inward.

The "direct pull" cantilever, also commonly known under its Shimano trademark name "V-Brake" is a simpler design, using only a single cable. The cable housing connects to one arm, and the inner cable runs across the top of the tire to the opposite arm. When the brake is applied, the housing pushes on one cantilever while the inner cable pulls the other.

Since the cable runs straight across the top of the tire, direct pull cantis need longer arms to get the cable high enough to clear the tire. This increases the mechanical advantage of the system, requiring the use of special matching brake levers.

Quick Release

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Normal Position
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Boot Pulled Away
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Noodle Unhooked

For wheel removal, the noodle may be unhooked from the arm link. This will allow the brake shoes to open up wide enough to clear even a fat tire. First, pull the boot away from the end of the noodle. Then squeeze the brake arms together with one hand while unhooking the lower end of the noodle from the keyhole-shaped slot in the arm link.

Make sure to hook the brake back up immediately after you re-install the wheel!

Parallel-Push Linkage

v-type brake
Some himano XTR, XT and LX V-Brakes feature a special parallelogram linkage. This serves two purposes: Unfortunately, the extra pivots considerably complicate the mechanism, and this has caused maintenance problems and excessive squeal in practice.

Direct-pull Brake Adjustment

First, remove the arms from the studs, and make sure the studs are free of rust. Coat the studs liberally with grease (this is VERY important!)

Install the arms with them at their maximum spread and tighten the bolts that hold them to the frame. This is how you set the springs.

Shoe adjustment is covered in the article about rim brakes, but there are a few special things about direct-pull brakes:

 

Centering

When the brake is released, the brake shoes retract away from the rim. Ideally, the shoes on both sides should back off by the same amount. If they don't, the brake is not properly centered. In extreme cases, one of the shoes may not retract, and may rub on the rim even when the brake is not being applied.

If a brake appears off-center, check first that the wheel is installed straight in the frame/fork. If the wheel is crooked, and you maladjust the brake to compensate, you are creating two problems where there was only one before.

Spring Adjustment

If your wheels are centered, and your brakes are not, and, if the pivots are properly lubricated and free-moving, the brake shoes should be centered. If they are not, you probably need to adjust the spring tension on one or both of the cantilevers.

Most direct-pull cantilevers have adjustable spring tension. The adjustment will be a small screw with the head facing outward to the side of the bike. The screw is generally located near the bottom of the cantilever, below the pivot point. Sometimes it works with a Phillips screwdriver; other times, a small Allen wrench may be needed.

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Tightening this screw tightens the spring, so you want to tighten the spring of whichever arm is too close to the rim. This will make it spring back farther.
  

Brake Levers for Direct-pull Cantilevers

Direct-pull cantilevers have double the mechanical advantage compared with traditional brakes, so they require special brake levers. Direct-pull brake levers pull the cable twice as far, half as hard. The lower mechanical advantage of the lever compensates for the higher mechanical advantage. of the cantilever. It is not generally safe to mix and match levers/cables between direct-pull and other types for this reason.

Drop-bar Levers

To make a brake lever with low enough mechanical advantage for direct-pull cantilevers, the cable must run twice as far from the lever's pivot point. This is easy enough to do with levers for straight/upright handlebars. Levers for drop handlebars are harder to configure for direct-pull brakes, and currently, there are only a couple of drop-bar levers made that are compatible, the Dia Compe 287V and the Cane Creek SCR-5V "Æro" levers.

Most newer drop bar bikes are have Ergo or STI brake/shifter units as original equipment. Direct-pull cantis are not compatible with these. Other types of shifters may of course be used, along with the special brake levers. In any case many cyclists prefer bar-end shifters. These are simpler and less expensive than brake-lever shifters, and give an indication of what sprocket is in use: brake-lever shifters return to the same position after every shift.

Drop-bar Workarounds

If you want to use Ergo or STI brifters with direct-pull cantis, there are two workarounds available: QBP Travel Agent

Neither of these systems is ideal, and neither is really any better than traditional center-pull cantilevers.

Compatibility

Note the differing levers and pivot stud positions.

Cantilever Brake Compatibility/Interchangeability
Cantilever
Type
Frame
Pivot Studs
Levers Cable Routing
Direct Pull
V-Brake ®
Below the Rim Long Pull
Low Tension
Cable comes in from the side.

Lower housing stop is part of the cantilever

Traditional
Center Pull
Standard
Short Pull
High Tension
Cable runs down the bicycle's center line.

Lower rear housing stop on frame,
either special braze-on ,
or mounted to the seatpost bolt.

Front housing stop on headset ,
fork or handlebar stem .

U-Brake
Cantilever
Above the Rim
Roller-Cam
Cantilever

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