Why Brakes?

Brakes are vital to the safe operation of your motorcycle…no doubt. Brakes are used on moving vehicles to bring them to a stop. That applies for motorcycles, cars, airplanes, and even we humans use our muscles and the grip/friction of our shoes or bare feet to stop in time before hitting the wall…ouch.

“Brakes” meaning brake shoes (as used on older motorcycles) or brake pads (as used on most newer bikes) are used in conjunction with hydraulics (master cylinder, brake calipers, brake hoses etc.) and its hydraulic clamping force, with the use of friction from the brake material against the brake disc or brake drum to stop you from hitting that hard object.

Brake Fluid:

Basic Hydraulics: Fluids cannot be compressed thus they are used as a medium to transmit force from the hand/foot lever to the master cylinder (which becomes hydraulic force) then via the brake hoses to apply clamping force via the brake calipers directly unto the brake disc. Brake fluid (Dot 3 or 4) with the exception of Dot 5 (silicone fluid) is hydroscopic, meaning that it will over time absorb moisture/water directly from the atmosphere. Remember: the brake master cylinder is vented via a small hole (directly located in the cover) to atmosphere, for proper function. Over time, brake fluid will change color from a light straw color or nearly clear in color to a dark brown or worse yet, almost black color. Tests have shown that a brown color indicates that the fluid has an approx. content of 25% water already. Therefore, it is vital from a safety point to flush out the bad brake fluid, since the absorbed water will boil within the brake fluid if the brakes are used hard and will give you that "OH NO" feeling when the brake lever pulls all the way back to the handlebar (because you have just compressed the air bubbles of the boiling water within the brake fluid). And that's usually when you need the brakes the most… in a panic stop.

Note: Brake fluid reaches high temperatures when riding in stop and go traffic or when going downhill in the mountains. Think: Constant brake applications. Dot 3 vs Dot 4:

The difference between the two fluids is the heat tolerance, thus Dot 4 fluid will tolerate a greater heat level, before the brake fluid itself begins to boil. CAUTION: Dot 3-4 and Dot 5 brake fluid are not to be intermixed. Dot 5 brake fluid is not approved for BMW motorcycles.

Using Brake Fluid:

When refilling your master cylinder, use only the recommended brake fluid as indicated on the cover of the brake reservoir. Refill only from a sealed brake fluid container. CAUTION: Never allow brake fluid to come in contact with the paint surfaces etc of your bike, as it will melt the paint etc., be sure to immediately clean off any spilt brake fluid with lots of water. Maintenance of Your Bike:

Seriously consider having the Annual Service done on your motorcycle, regardless of the mileage. Brake fluid flush is part of it…since the brake fluid gets dirty/absorbs moisture just like the engine oil. Also consider the consequences if it not done on a timely basis: moisture will damage the vital components such as the ABS Hydraulic Pump Unit.

Using Your Brakes:

Just like the racers: ya can’t go fast if ya can’t stop. As taught in the MSF courses, learn to use your brakes effectively, for the “sudden stoppage” will get you each time, as they say in the airplane business. Thus practice panic braking to hone your skills in getting the bike stopped in a big hurry. Certainly it is wise to practice panic braking in a safe location, such as an empty parking lot. You can increase your braking feedback by pressing your knees against the gas tank while applying full brakes. A Word About ABS Brakes: The beauty about ABS brakes is that you can still control the direction of the travel while braking, thus sometimes you can go around the danger/object…certainly helpful. When in ABS mode, it will certainly apply/release the brakes faster than you can manually, while keeping the tires from skidding. Remember tires slide only when locked up or when spinning, which in turn creates an unstable situation…the bike goes sideways! And so does a car/truck. Standing on the foot pegs at this time may help gain control of the bike.

CAUTION: Mother Nature will remind you that you cannot defy gravity, inertia, etc., not even with ABS brakes!! Remember that if there is little or no friction/traction (think: ice, snow, rain, sleet, gravel) between the tires and the road surface/ground then the bike cannot stop in due time, because it is not getting enough traction via the tires to the ground. Thus inertia will carry you out of the curve off into the boonies or likewise, you may hit that object you just wanted to avoid. Similarly, the safety effects of ABS are reduced somewhat when the bike is leaned over hard in a corner, i.e., if you're going way to fast in the corner, you could still wash out, ABS or not.

Brake Pads and Brake Discs: These two vital components do all the work and generate lots of heat. The action results from turning the bike’s inertia into heat via the friction of the brake pads against the brake disc in order to stop your bike. Both items wear out, meaning that they should be checked and replaced in due time before metal to metal contact of the brake disc and brake pad backing plate occurs. As part of our routine safety check while your bike is in for any service, we will check the brake pads for remaining thickness and advise you if the replacement will be necessary before the next scheduled service is due. We recommend staying with the BMW stock brake pads since these, like your tires, have been extensively tested by BMW to provide the best possible performance.

Brake Hoses: Brake hoses will wear out over time. Routinely check your brake hoses for chafing, ballooning bulges, scrapes, dry rot, ozone damage. A spongy feeling hand or foot brake usually indicates a problem.

Also: Replacing rubber brake hoses with stainless steel versions will change the brake feel and feedback (if only little). It will take some time and practice stopping to get used to the “new feel” which is usually a more abrupt ON-OFF braking feel. Stainless steel brake lines were first on the Butler & Smith roadracers in the early 1970’s to improve the stopping under racing conditions.

Brake Dust:

When working on brakes, avoid the brake dust which usually over time covers all the brake components and wheels. Wash and dry these items first, before beginning the work. Also, remove brake dust from the cast wheels routinely, since over time the brake dust can etch and discolor those beautiful wheels. When washing your bike or car, use a separate sponge and wash those dirty wheels last, thus avoiding the scratching effect of brake dust on the painted surfaces/body panels.

We are here to help and advise you on your brake system, so call us or come by should you need any assistance.

Because motorcycles like all motorized vehicles travel down the highway at speed. The suspension system must provide among other things, ride comfort; secure handling (for those emergency situations), optimum braking power.

It Is Not All Suspension Springs Suspension springs, either the front springs within the front fork assembly or as part of the shock absorber on the Tele-lever system, or the rear shock(s), are used to carry the weight of the bike, including rider/passenger/luggage. Hint: Since suspension springs are under constant compression due to the weight of the bike and rider/passenger/luggage, they are subject to collapsing over time. This will alter the correct ride height and handling characteristics of your bike. The opposite (as an example) occurs with the ignition advance springs on older /5, /6, etc. bikes. These springs are constantly stretched and, over time, could alter slow timing and idle speed. Therefore, all springs under tension will eventually lose their original force.

Shock Absorbers - Controlling the Bounce

The function of the shock absorbers is to control the bounce/pogo effect the suspension springs would deliver after they are compressed and rebound, such as going over a bump on the road surface. Have you ever pushed down on the fender of an old car with worn shock absorbers and seen it bounce up and down? This uncontrolled bounding can be downright scary on a motorcycle! Control is accomplished by filling the shock absorber body with oil and forcing the oil from one chamber to the next via a fixed set of oil bores as the suspension moves up (extension or rebound) and down (compression). Thus a dampening force (or damping, in suspension lingo) is applied in both directions to prevent the suspension springs from acting like that pogo stick we may have owned as kids.

Ride Height - Keeping Things at the Right Level

Ride height determined by design and testing is the correct height of the bike to the ground. This means that the bike is balanced so that the front and rear suspension can operate in unison and function well for many different riders.

Where do I start?

Please do take the time to read your Owner's Manual, especially those pages dealing with suspension adjustments. Should you have any questions regarding the suspension adjustments, please come by for additional help. Remember that your bike is capable of allowing you to make a number of suspension changes. Rear suspension "preload" is easiest to understand and adjust. The more weight the bike is carrying (gear or passenger), the more preload (or spring tension) is required to keep the ride height correct. CAUTION: Do not exceed the maximum weight limits for your model as set forth in the Owner's Manual. Those extra pounds will indeed affect the handling (tires will slide and things will bend), especially when you need it the most: in an emergency. Remember that your tires will affect handling as well, so mind those tire pressures and reread our prior Newsletter on Tires.

It All works Better in Unison BMW's typically require more damping than spring pressure. Many riders, however, make the mistake to ordering stiffer springs for their bike…. remember the Pogo stick? Additional bracing of the front forks, swing arm and frame was originally done to the Butler & Smith roadracers for conditions on the racetrack (sometimes for each track), and for the riding styles of the different riders. Some of these items may indeed make your suspension too stiff for the street, thus increasing the potential for instability. Other factors come into play: Do not forget to check your wheel bearings, swing arm bearings, swing arm bushings on the rear Para-lever, and steering head bearings. If not adjusted or maintained correctly, each can affect handling.

Some thoughts on Suspension Tuning We do benefit from the constant development and testing, as done by BMW. It appears that today's bikes offer better handling and are to a certain extent more forgiving and safer. Constant tire technology improvements and ABS brakes have helped, as well. Nearly all riders should be satisfied with the handling of the BMW. Aggressive changes in your spring rate, compression damping and rebound damping my hurt more than help. In most cases, factory or approved aftermarket shocks (for example, Ohlins or Bitubo) standard settings are fine. Just be aware that springs do collapse and shock absorbers will loose their dampening in both directions over time. When in doubt, please ask us to check your suspension during a service.