BICYCLE REPAIR
While bicycle brakes offer excellent stopping
power, over time the cables may stretch, the brake pads wear and a pad
might drag on the rim. Because your safety depends on optimum braking,
here are guidelines for common adjustments to ensure that your grippers
are always at their best.
Please note: These instructions are for
conventional brakes, not disc brakes. Also, because brakes are so important
for safety, do not work on your brakes unless you’re confident in
your ability to do the job right. And, keep in mind that in order for
brakes to work properly and to make the adjustments explained in this
article, the wheels must be true and round (no side-to-side wobbles, up-and-down
hops or bends).
Tightening the Brakes
For off-road, comfort, hybrid and city bikes with upright handlebars; look at the brake levers for a handy device called an adjusting barrel (photo).
It will have a knurled edge for easy gripping and it makes adjusting your brakes easy without tools. It’s perfect for making your brakes feel like new after you’ve logged a good many miles and worn down your pads. And you can even use it on rides if your brakes begin to feel weak as sometimes happens when it's muddy or wet.
To use adjusting barrels, turn them counterclockwise by hand and check the setting by squeezing the levers. When the brakes feel right, lock the barrel adjusters in position by turning the lockring (the second knurled piece) clockwise until it's tight against the lever.
On road bikes with dropped handlebars, you’ll find the adjusters on the brakes (photo below). To tighten the brakes, turn the adjusters in the direction that moves the pads closer to the rims.
Keep
in mind that when your brake pads wear out, the adjusters won’t do
any good and you’ll need to turn the adjusters all the way back and
replace your brake pads.Wheel Centering
One of the most common brake problems is a dragging brake pad; one that remains against the rim or stays close to it after you’ve released the brake lever.
The most common cause of this problem is a misaligned wheel. This can occur when you reinstall your wheel after removing it to put your bike on a roof rack or to fix a flat tire, and you don’t get it exactly centered in the frame.
This causes the brake to work improperly because it’s tight on the frame and has been adjusted to align properly only on a perfectly centered wheel. Now that the wheel is crooked in the frame, the brake can't work correctly.
To correct the dragging shoe, simply center the wheel in the fork or frame. For most wheels, all that’s usually required is loosening, making sure they’re fully inserted in the fork or frame, and tightening them. (If the bike is standing, just press down on the handlebars for the front wheel and the seat for the rear wheel to push them fully into the frame and center them.)
If you have a frame that lets you place the rear wheel in different positions, check that the wheel is centered between the seatstays and chainstays before tightening it. You can do this by looking at it or use your fingers as “feeler gauges” by sliding the same finger on each hand between the frame and rim or tire feeling if it’s centered (photo; the brake was removed so you can see the details).
Brake Centering
If your wheels are centered and the brake still drags, the brake may have gotten bumped and knocked out of position on the frame. Start by double-checking that the wheel is centered in the frame because you don’t want to ruin the brake adjustment if it’s actually set correctly.
To center sidepull brakes (road bikes), loosen the attaching bolt behind the fork crown or brake bridge until the brake is loose. (It should move sideways when you push it).
Now, squeeze the lever to hold the brake pads against the rim while you
tighten the brake bolt on the back of the frame. If the brake needs minor
fine-tuning after this, look for a small screw (it might be an Allen type)
on top of the brake. Clockwise turns (photo left) will
move the brake shoe on the side of the screw away from the rim and vice
versa. (This screw is not intended for major adjustments.)If adjusting the screw doesn't center the brake, screw it back to where it was and double-check how well centered the wheel is because that's probably the problem.
To center linear-pull brakes (off-road and hybrid bikes), look for a small
screw
in the side of the brake arm. Clockwise turns of this screw (photo
right) will move the pad in the arm with the screw away from the rim and
vice versa.Brake Binding
Brakes should operate smoothly and easily and the brake pads should snap away from the rims when you release the levers. If not, the brake pivots or cables might be dry, causing binding. To free the pivots, lightly lubricate the brakes where the arms pivot (photo below) and squeeze the levers
repeatedly
to work the lube into the brakes. (Be sure NOT to get any lube on the brake
pads or rim. If some gets on them; wipe them clean with rubbing alcohol.)Better? If not, it might be the cable that needs lube. Usually, this is only required on rear cables with split housing (if you have split housing you can see the middle of the inner cable and the housing is in two pieces).
Look closely at where the housing sections enter the stops on the frame. If the stops are split, you’ll be able to remove the housing and lubricate most of the cable. If the housing stops aren't split, raise the bike so that gravity will draw the lube into the housing section, apply a few drops of lube on the cable and squeeze the rear brake lever to draw the lube into the housing. Repeat for the front section of housing.
If the housing stops are split, open the quick release on sidepull brakes or unhook the noodle on linear-pulls. This should provide enough slack so that you can pull gently on the housing sections and free them from the frame stops (photo). If you need more slack, squeeze the brake shut with your hand.
When the housing is released from the stop, slide the rear housing section (with flat-handlebar-equipped bikes you’ll be able to slide the front housing section, too) along the cable so that you can lubricate the cable where it runs inside the housing, which should eliminate the binding. Then reconnect the cables and your brakes should feel as good as new.
