Cycling Brakes

U brakes, named for their shape, are used on racing and mostother road bicycles. There are various variants like center pullbrakes (Campagnolo Delta, an excellent brake but just tooexpensive), and side pull brakes. The smaller they are the betterthey work because less material means less flex. There are cheap Ubrakes that would fit around your arm that you can watch bendingwhen you brake. Good brakes are Shimano 105 and up, and anyCampagnolo brake. Quick-releases help removing the wheel; Shimanointegrates them into the brake and Campagnolo integrates them inthe brake lever. You can ride Campagnolo levers with Shimanobrakes but vice versa is difficult.

Cantilever brakes are most often used on mountain bikes andhybrids whose tires are too fat to fit a U brake. I do not likecantilevers because they are hard to adjust and require continuousreadjustment as the brake pads wear down. They tilt against therim, which means that unlike U brake pads, cantilever pads do nottouch the rim at a constant angle, so the angle must be readjustedfrequently. Unfortunately, loosening the one single nut thatsecures the brake pad makes the whole assembly come loose and youhave to adjust some six degrees of freedom all at once. Somepeople use spacers to adjust the pads while they press the spacersagainst the rim.

Magura cycling brakes replace cantilevers with two hydraulic cylindersthat push the pads straight against the rim. Like regularcantilevers, they need a *brake booster, a flat U-shaped piece ofsteel that connects both brake halves to keep them from pushingthe fork apart. Maguras work really well; if they weren't soexpensive I'd vote for throwing out all cantilevers.

There are other forms, such as Shimano V brakes, but I have noexperience with them. Hub cycling brakes are often used on cheap bicycles;there are also high-quality hub and disc brakes that are usefulfor tandems which are much harder to stop. Hub and disc brakeshave the disadvantage that they brake the hub, and a lot of forceneeds to be transmitted to the rim through the spokes.

There are a variety of brake pads that vary in softness. If the rubbercompound is too hard, it doesn't brake well, especially in wet weather;if it is too soft, it wears down too quickly. Since rubber tends to getharder with time, brake pads should be replaced at least every couple ofyears. I prefer Campagnolo or Aztec. Some brake pads are longer thanothers, but I have not found this to make a difference. Some brake padsare designed for steel rims, but they don't make steel rims safe - neveruse steel rims because they are difficult or impossible to brake in wetweather. Good brake pads are not cheap, but this is about the worstplace to save money!

In road bike shift levers of the kind used for drop (racing) handlebars,the brake cables connect to the inside of the handle and run along thehandlebars under the handlebar tape. The older type where the brakecable connects to the upper tip and arc up and then back down to thebrakes are dangerous because you can accidentally catch the cable withyour gloves, especially if you have aero (triathlon) bars.

Content by Thomas Driemeyer, www.bitrot.deEdited by Reg Gupton, gupton@growthseminars.com

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