Braking in your bike
Keeping your brakes in good shape will make you a more confident, and therefore a more capable, rider, explains Stephen Huntley.
Bike brakes are a very reliable and efficient mechanical device that work well even if not perfectly adjusted. For this reason, although ongoing brake maintenance is quick and simple, it is often ignored. Many seem to reason that if the brakes worked okay last time, they should work okay next time.
And that may be true for most situations, but what if next time you’re moving quickly down a hill when suddenly another bike rider, or a child, or a car, suddenly pulls out in front of you? Will your brakes be up to the job of pulling you up? Take the guesswork out of the equation by keeping on top of your brake maintenance.
In this article we will be concentrating on the two most common types of rim brakes; the dual-pivot brakes found on many road bikes, and the V-brakes found on many mountain bikes and some road bikes.
Keep it clean
Dual pivot and V brakes use a wheel’s rim to act as a braking disc, which leads to some big advantages over other braking systems, but one of the downsides is that because rims run close to the road, they can become very dirty.
Road grime mixed with brake pad dust leaves a grey, hard to remove residue on the rim that decreases braking efficiency. Isopropyl alcohol (also known as rubbing alcohol) is traditionally recommended as the ideal rim cleaner. It cleans away the grime quickly but unlike other solvents, leaves no residue behind (it’s also popular for cleaning computer components).
You can find spray bottles of 100% isopropyl made by Diggers for about $8 in Bunnings and Big W; look in the section selling solvents such as methylated spirits.
Riding in wet weather will cause rims to pick up a lot of abrasive grit and silt. When you get home after a wet ride, rinse the rims to clear the grit off. It’s also a good idea to occasionally remove your wheels and give the brake pads themselves a scrub, while removing any bits that are lodged in the pads; they will hinder braking and gouge the rim.
Mind the gap
Ideally, brake pads will sit just a couple of millimetres away from the rim, but as the pads wear away, and cables stretch, this distance will increase. It is a quick and simple process to adjust this distance, and you should do so whenever necessary.
Your bike will have a barrel adjustor either near the brake lever (V brakes) or the brake arms (dual-pivot brakes). See our photos for guidance.
These adjustors may have a lock nut you will have to loosen before screwing them in or out. By screwing the barrel adjustors outwards from their holder (counterclockwise turns) you will pull on the brake arms, bringing the pads closer to the rim.
If you have unscrewed the adjustor almost to its end but there is still too much of a gap between pads and rim, you’ll have to take a slightly more complicated approach.
Screw the barrel adjustor in (clockwise), stopping when there is about 3mm of thread left to go.
Squeeze the brakes arms together with one hand, so the pads are against the rim, and with the other hand undo the anchor bolt that attaches the cable to the brakes. Pull the cable through the bolt housing so it is as taught as you can manage (use pliers if necessary), then retighten the bolt against the cable and let go of the brakes.
Now work your brakes on and off a few times. Spin the wheel. It is likely that the brakes will have slipped back off the rim a little, but may be too close. By screwing the barrel adjustor further in (clockwise) the pads will move away from the rim. After each adjustment, work the brakes a few times and spin your wheel. You’ll quickly find your ideal gap.
As a final check, make sure the bolt clamping the brake cable is tight, and do some test braking before going for a ride.
Look down at your brakes and check to see if both pads sit the same distance from the rim. If not, make sure your wheel is centred correctly, and adjust if necessary.
Next lubricate the pivot points of the brakes with oil, being careful not to get any on the brake pads or rim surface. Try the brakes out a number of times and see if this helps.
If not, you’ll have to do some further adjusting. V-brakes have an adjustment set screw located toward the end of either brake arm. Start with adjusting the pad arm closest to the rim. Screw its set screw in (clockwise) and the arm will move away from the rim. If necessary, do the opposite to move the other arm in. Continually apply and release the brakes while adjusting.
For dual-pivot brakes, first ensure the entire caliper unit is centred correctly in your bike frame; if not, loosen its mounting nut, rotate the unit until it is centred, then retighten. Apply and release the brakes a few times. If there is still an uneven gap, adjust the centring screw (see illustration). Tighten the screw (clockwise) if the right pad is closer to the rim, loosen the screw if the left pad is closer.
Get in line
Brake pads are often set on an incorrect angle, which can lead to dangerous wheel failures. Squeeze your brakes on (I like to wrap a Velcro strip tightly around the handlebars and brake lever to keep the brakes on while doing this inspection), get down low and have a close look at where your pads are sitting against the rim.
If the pads are resting high on the rim, the top edge of the pad may be rubbing against the tyre. With regular braking the pad will quickly wear through the tyre, expose the inner tube, and ‘kaboom’; you’ll be running on your rims.
If it sits too low, only part of the pad might be wearing away, causing poor braking, and eventually the pad may slip off the rim and into the spokes, sending you over the handlebars in the process.
The leading and trailing ends of the pad should align with the rim, with neither end being higher than the other. Looked at from directly in front, or behind, the pad surface should also be flat against the rim.
If the pads aren’t sitting in a good position, loosen the bolts that hold them in place, and while they’re still sitting against the rim, manipulate the pads into correct alignment, then tighten their bolts again.
You may find that in the last few turns of tightening the bolt that holds the pad in place, the pad itself starts to twist clockwise. For right-side pads, keep a finger firmly in place against the back of the pad to stop it twisting, and for left-hand pads, keep a finger firmly in place against the front of the pads.
Once the pads are aligned, use the brakes a number of times, take another look, and readjust if necessary. Take your time, be pedantic and get it right.
Sometimes brakes can emit an annoying, attention-grabbing squeal. It is caused by the brakes alternatively gripping and releasing, causing vibration in the brake arms. Because of the length of V-brake arms they are more likely to be guilty of this audible distraction.
First suspect a dirty rim is at fault, and clean it with isopropyl, as mentioned earlier in the article. Also clean the brake-pad surfaces. If that doesn’t work, it is possible that your pads don’t ‘toe-in’ correctly. Apply your brakes slowly while you’ve got a good, close view of the rim and pads. Does one end of the pad hit the rim slightly before the other end?
If the front end connects first, that’s fine; you’re pads are correctly toed in. If both ends hit at the same time, that would also normally be fine, particularly for dual-pivot brakes, but you may want to try toeing them in to see if it eradicates the squeal. If the back end is connecting first, this is the likely cause of the problem.
Most brake pad housings have spherical washers that will allow the brake pad to be tilted as it is tightened. A simple way to achieve toe-in is to loosen the pad bolt a little, apply the brakes but have a slim piece of cardboard, or a rubber band, sitting between the back of the pad and the rim. Align the pad correctly, then tighten the bolt. Release the brakes, remove your cardboard/band, and slowly apply the brake again, watching to make sure the front end of the pad hits the rim first. If not, try again!
If there’s still a squeal, replace the pads.
You brake pads are designed to create friction, and to gradually wear away. Softer brake pads will usually grip better, particularly in the wet, but will wear away faster than stiff pads.
Many pads have indentations that act as wear markers; once they disappear it’s time to buy new ones. Old brakes can also become very stiff and brittle, and not very effective. If you’re finding your brakes are slipping, get new pads.
Pads for V-brakes come as a complete unit, including the backing shaft, washers and bolt, while with most road-bike dual-pivot brakes, the pad itself can slide out of a holder, and a replacement pad is then slid in.
Take your worn pads to your bike shop as a guide to what you need. If your dual-pivot brakes don’t have slide-in pads, you may want to upgrade to them for future use, as they are very convenient and may eventually save you money.
Out with the old
Replacing pads yourself can be a little bit fiddly, and sometimes frustrating, but it is not particularly difficult. Give it a try, but make sure you test your work thoroughly before taking your bike out on a ride. If after trying to replace your pads you feel things aren’t working well, go to your bike shop and have them finish the job off.
New brake block unit
You’ll first need to create slack in the brake cable by unscrewing the adjustor barrel all the way in (clockwise).
For V brakes, squeeze the brake’s arms together and pull back the rubber sleeve protecting the cable, near the noodle. Note how the noodle sits in its hanger, with its nose through a gap. Pull the nose back out of that gap, and the noodle should disengage.
For dual-pivot brakes, there is likely to be a quick release pivot bolt on the brake unit; spin it up to release more cable. Campagnolo brakes have a quick-release button on the handlebar’s brake levers.
Now you can get at the brake pads. Undo their bolts, making a careful note of the order of the washers, and which direction they’re facing, as you do so.
Bolt the new pads loosely in, ensuring any directional arrows are pointing forward (if a pad has a longer end, it will go to the rear). Squeeze the brake arms together, and tighten the quick release for dual-pivots, or slip the noodle nose back into its hanger on V brakes.
Undo the barrel adjustor a few millimetres. Squeeze the brake arms together again so the pads are against the rim, then loosen the bolt anchoring the cable to the brakes. Pull the cable taught and retighten the bolt. Let go the arms and use the barrel adjustor to position the pads the correct distance from the rim.
Adjust the alignment of the pads as per our earlier section. Test thoroughly before going on a ride.
Create slack in the brake cable (see last section), unscrew the retaining screws that hold the pads in their shoe and slide the old pads out (towards the rear). Insert new pads, taking care to follow any directional arrows that indicate a left/right pad, and which end is at the rear/front. Screw in the retaining screws.
Reset the brake cable then undo the barrel adjustor so a few millimetres of screw is showing. Squeeze the brake arms together so the pads are against the rim, then loosen the bolt anchoring the cable to the brakes. Pull the cable taught and retighten the bolt. Let go the arms and use the barrel adjustor screw to position the pads the correct distance from the rim.
Adjust the alignment of the pads as per our earlier section. Test thoroughly before going on a ride.
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