JIM'S TECH TALK

RBR Newsletter

3-Step Brake Tune-Up

While we’re starting to see road-style disc brakes, sidepull rim brakes are still the default stoppers found on performance road bikes. The basic design, featuring calipers that squeeze the rims for speed control and safety, has been around for over a century -- and for good reason. It’s light, powerful, simple to adjust and repair, and maybe best, impressively durable.

Fact is, you might need multiple shifting adjustments and even wear out several chains and cassettes before you need to do anything to your brakes besides tightening them with the adjustment barrels and replacing worn brake pads. But, this doesn’t mean you should ignore your brakes. Instead, every 1,000 miles or so, do this quick check (more or less frequently depending on how hard you use your brakes).

Tip: I’m assuming your road bike is in good condition and not in need of major service after years of use without regular repairs. This quick brake check won’t solve serious brake issues like deeply grooved rims, dead brake springs, fraying cables, cracked housing, etc.

Check the wheels for trueness and the rims for cleanliness

“Old-fashioned” sidepull brakes are actually a type of disc brake, when you come right down to it. The rims just take the place of the rotors on the discs. So, the first step in tuning brakes is making sure your rims are ship-shape.

First, spin the wheels and watch for side-to-side wobbles or hops. Ideally they’ll be true and round with no visible imperfections that can cause pulsing or grabby braking and a loss of control. If you spot problems and have the skills, true the wheels. Or have it done by a professional.

Follow that check by looking closely at the braking tracks on the sides of the rims. They should be smooth and clean all around. If you see black marks on the rims, clean them off with a medium-rough piece of emery cloth or sandpaper, or a solvent like alcohol. If you use sandpaper and end up roughing up the surface to remove the black marks, continue around the rim to make the entire braking track equally rough.

Tip: Rims are tougher than they look. Sanding them a little won’t hurt them. If you don’t have any emery cloth or sandpaper, or if you’re trying to tune your brakes on a ride, you can use the piece of sandpaper in your patch kit. Bonus tip:  sanding rims is a good way to stop a squeaking brake, too.

Check and lube the calipers

The calipers attached to the frame are the hardest working parts of the brake system. Because they can loosen, make sure they’re securely attached front and rear by tightening their attaching nuts behind the fork crown and brake bridge (usually it’s a recessed 5mm allen bolt on modern road bicycles). But, BEFORE tightening the attaching nuts, squeeze and hold that brake’s lever. This will ensure that as you snug the nut the caliper will remain centered and not get twisted out of position.

Next, stuff a rag inside the brake and over the tire/wheel. Make sure the brake pads are covered. You’ll now be able to drip or spray lube on the back of the caliper to get lube inside the pivot point(s), under the brake spring tips that ensure the caliper opens fully and operates freely, on the quick release to prevent corrosion and keep it opening/closing nicely when you need it and on the adjustment barrel so it turns for tightening the brake. Operate the brake several times to work the lube into it. Then wipe off any excess.

Tip: Even if you lube your caliper, if it has a quick-release mechanism and/or adjustment barrel built in (some calipers don’t), you should take the extra step of opening/closing the quick release and turning the adjustment barrel. This will get the lube between the parts. If you don’t do this, the lube may sit on top and the parts can end up corroding and not working when you need them.

Check the brake pads

Modern sidepull brakes usually have easy-to-replace brake pads. They just slide in and out once you’ve loosened a set screw. It’s a wonderful design because it means you don’t have to align the brake pad with the rim, which takes time, patience and isn’t easy to get right for even professional mechanics.

But you do still have to keep an eye on your brake pads to make sure they’re not worn out. To tell, look for noticeable grooves in the face of the pads (the surfaces that touch the rims). When the grooves have disappeared, you won’t have much thickness left to the pads. With some brake pads, if you let them go too long, the metal holders will begin scraping on the rims, in which case, hopefully your other brake will still have enough rubber to stop you.

Worn-out pads should be replaced. I always keep a set in my home shop so I can replace them should I discover mine are worn-out the day before an important ride. It only takes a few minutes to put them in.

Just like how rims can develop some wear and deposits that affect the braking, pads can, too. So, if your brake pads still have some life in them, inspect them as well. You might find bits of aluminum from the rim embedded in the pads, or bits of gravel from the road.

Dig anything like this out of the pads with an awl or pick so that it’s just rubber against the rim when you brake, never metal or stone. You might also have black deposit or other hardened material on a pad. Fix these issues by sanding the imperfection off. Using the sandpaper from your patch kit will work in a pinch as it did for the rim.

Tip: As the brake pads wear down, you have to squeeze the brake levers further to get the same stopping power. To keep the braking effort the same, simply use the adjusting barrels to tighten the brakes. But, remember that you did this when you’re replacing your worn-out pads, and turn the adjusters all the way back. If you don’t do this, your brakes will be too tight to install the new pads and that might fool you into thinking something’s wrong when you only need to reset the adjusting barrels.

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Jim Langley has been a pro mechanic and cycling writer for more than 40 years. He's the author of  Your Home Bicycle Workshop in the RBR eBookstore. Check his "cycling aficionado" website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim's streak of consecutive cycling days has reached 7,587.

 
 
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