Motorcycle Brake Mod Test: Slower Is Faster
This article was originally published in the June 2017 issue of Dirt Rider.
You can only go as fast as your brakes allow you to slow down. That doesn’t sound quite right, does it? But if you don’t have good stopping power on your dirt bike, chances are you will not be able to get around the track or scoot down that trail at any reasonable rate of speed without missing your mark or crashing. Most of today’s off-road motorcycles come stock with fairly good brakes and are usually plenty capable for 90 percent of the riders out there. But what about those 10-percenters who want just that little extra or maybe are super picky about how their brake engages or feels? We wanted to “brake” down several ways that you can alter your brakes’ performance to get the most out of that lever and pedal.
Who comes with the best stock brakes, out of all the new off-road machines? KTM has used Brembo brakes, Galfer rotors, and steel-braided brake lines for quite some time. This combination has proven to be the most powerful, yet the most progressive, way to get stopped or slowed down from an off-the-showroom dirt bike. If you’re on a Nissin brake system, using some of these modifications below will get your bike to this point, or using all of these mods will get you past it.
A fixed brake rotor is a simple, solid, one-piece rotor. A fixed brake can also increase lever pressure and power but is susceptible to more warpage when hot due to its solid mounting points. Fixed rotors are lighter than a floating rotor, and, remember, rotors are unsprung weight, which is key to a bike’s handling on motocross machines. A floating rotor system uses bushings that attach a mounting bracket to the brake area where the pads grab. The bushings offer a slight bit of play, allowing for a more centered or equal grab by pads, leading to more even pad wear. Also, in case of an impact, floating discs can take more abuse than a fixed disc. However, floating discs are heavier and more expensive.
This is the most common of all brake purchases. An oversize rotor can dissipate heat more (due to its larger circumference), increase brake pad life, and increase the stopping power to your front brake lever because of its extra leverage. Most stock competition off-road bikes come with a 260mm or 270mm front rotor and a 240mm or 245mm rear rotor. Aftermarket brake companies usually offer their “oversize” front rotors in either 270mm or 280mm. When going to a larger rotor than stock you will need to also change the caliper carrier, which usually comes with the rotor.
Steel-braided lines reduce expansion when the brake fluid gets hot. This keeps the lever engagement consistent and in the same spot over a longer period of time. The life span of a steel-braided line is longer than a standard rubber/nylon line that comes on most machines. You get more consistent feel at the lever, and consistency is key for any rider.
Another option for Nissin brake riders is installing an aftermarket brake caliper. A couple companies offer different calipers (Ride Engineering and MotoStuff) that can dramatically increase your stopping power. An aftermarket caliper has pistons that are larger than a stock Nissin caliper, and with this comes increased power at the lever. But unlike just going to an oversize rotor, a caliper can give you a more progressive feel. Going to larger pistons changes the leverage ratio when using the stock 11mm master cylinder that most Nissin-equipped bikes come with (Honda, Kawasaki, Suzuki), so it feels more gradual and less grabby. Flex is also reduced and airflow is increased with wider fins.
If you’re a picky rider and want to take it even further for that personal touch, there is the ARC adjustable front brake lever. The ARC lever lets you choose from three degrees of lever ratio that will let you dial in where you want the lever to grab. Some riders like a very touchy lever right at the beginning of its pull, and some riders like the lever to grab closer in to the handlebar. With the ARC adjustable front brake lever you are able to dial in your personal setting.
People often ask if they should use DOT 4 or 5 brake fluid. There is nothing wrong with sticking to DOT 4 brake fluid. Its boiling point is plenty high for any modification that you have read about here. However, do not mix DOT 4 and 5 together. DOT 4 is a glycol-based oil and DOT 5 is silicone based. If mixed, your brake will start to feel mushy and less powerful. DOT 5.1 is glycol based and can be added to DOT 4 if necessary, but it is also wise to flush your brake fluid out completely before adding anything different.
On The Track: No performance difference was felt on the track with DOT 4 or 5 brake fluid.
Many companies offer the option of brake pads made with different types of material to alter the response and power of the pads’ feel.
On The Track: After some time riding on rotor-kit-specific brake pads and using stock OEM pads, we say stock pads usually wear more consistently (longer) and have a less grabby feel than most aftermarket pads. Some sintered pads were as powerful as OEM, but nothing proved to be any better than a standard OEM brake pad. We experienced more noise (squeak) on some rotor-kit-specific pads when dragging the brakes, more so than OEM pads. Riders who are known to be brake draggers preferred sintered pads, as heat buildup wasn’t quite as bad as OEM pads that were not sintered.
All of these mods above will help your stopping power, but it is how you want that stopping power delivered that should guide you on which of these mods you make to your machine.