How To Get Great Braking Power

Simple hacks to halt.

This is the year we’ve noticed that it’s no longer odd to see lots of disc-brake bikes on any ride – from hardcore roadie world-championship-grade training grinds to the weekly mates’ ride to the urban pub crawl, the brakes that were once a staple only on mountain bikes have become the standard. (Even World Tour teams have been riding them during cycling’s biggest races, since the UCI approved them for the 2018 season.) And even the purists at Bicycling who vehemently resisted discs on aesthetic principles have accepted their excellent stopping power, superior speed modulation, and better allweather performance. Whether you’re a holdout or already rocking them, here’s how to make the most of discs.

// THE BASICS: MECHANICAL VS. HYDRAULIC

There are two main types of disc brake: mechanical, which works with cables (just like rim brakes), and hydraulic, which replaces the cables with hydraulic fluid in a fully sealed line. When you

brake, the pressure forces the fluid to move into the caliper, pressing the pads against the disc.

If you’re interested in buying a discbrake-equipped bike on the cheaper side, you’re probably going to end up with mechanical brakes. This lower-cost option will allow you to spend less and still own a bike with reliable, all-weather stopping power. Apart from price, some riders prefer cable-activated disc brakes because they’re easier to work on at home, and they’re compatible with most mechanical brake levers. But more bikes are coming stock with hydraulic disc brakes. This pricier option is generally more difficult for the home mechanic to maintain. We suggest getting a shop mechanic to bleed your brakes (the old hydraulic fluid is flushed and replaced with fresh fluid). While this costs more than replacing cables, it only needs to be done every six months.

THE INTERMEDIATE SKILL: ALIGN YOUR CALIPERS // AND ROTORS

If your rotor doesn’t spin freely, you’ll know – the resulting rubbing, grinding, and squealing will drive you nuts, and cost you some momentum. Usually, the caliper is misaligned. Fix this by loosening the two bolts attaching the caliper to the frame or fork just enough so that the caliper can move side-to-side. Wiggle the caliper to make sure it moves freely, then pull the corresponding brake lever hard. This will clamp the caliper to the rotor. Hold the brake lever down to keep the caliper in place while tightening the top and bottom bolts until snug. Then retighten the top bolt to torque spec, followed by the bottom bolt.

If you’ve adjusted your caliper but still hear rubbing, check your rotor – sometimes they warp from a hit or excess heat.

“Almost no rotor is perfectly straight,” says Mike Perejmybida of VeloFix in Ontario, Canada. To find out if your rotor is warped, set the bike in a stand or flip it over so the wheel can spin freely. Look between the pads for a wobble, or a gap opening and closing. If you see either, the rotor is out of true. Often, but not always, warped rotors can simply be bent back using a rotortruing tool like the Jagwire Disc Brake Multi-Tool. Note the section that needs truing, and rotate it away from the caliper. Gently work the tool around the rotor at that section to straighten it.

This only works if the rotor is rubbing in one specific spot. If you’re unsure if it’s the rotor or the brake, you’re better off taking your bike to a professional to get it done properly. Rotors are strong stoppers, but are fragile side-to-side. “If you do try it yourself, be very gentle,” Perejmybida says.

// THE EXPERT HACK: SAND YOUR ROTORS

Once you’ve put some big hours in on your disc-brake-equipped bike, you’ll start to incrementally wear down the pads and the rotors. If your brakes start to feel less effective but you’re certain there’s still life left in the pads and that everything is aligned, check to see if the rotors look glossy. If so, it’s time to grab some sandpaper and get to work.

Opt for a minimum of 200-grit sandpaper. Remove your wheels, then gently sand each rotor until the glossy haze disappears and you see a dull colour with a slightly textured finish. With this new texture, your bike’s rotors will provide more friction against the brake pads when you pull the levers, restoring the performance you expect from discs. This inexpensive hack isn’t a cure-all, but it has helped our staff mechanic and logistician, Joël Nankman, extend the life of disc brakes for years.