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amount of friction and initial bite ) and graphites ( the level of which controls the amount of brake dust produced ). Tungsten additives are also used to enhance friction performance . A premium sintered pad has a smooth surface , whereas a lower quality pad has a rougher feel , as the metal particles aren ’ t so finely cut or evenly distributed , and acts like wire wool on brake discs .
Which pads are good options ? Sintered pads ( designed for use with stainless steel discs ) are good for a lot of uses . Sintered pads originated from aircraft brakes as planes needed consistent braking in all-weather conditions and a sintered composition worked best . Characteristics include high initial bite and decent braking power at low temperatures as they ’ re made out of aggressive materials .
What about backplates ? Higher end pads have a high-grade metal backplate and even a sprayed-on bonded ceramic heat shield . This keeps the pads hot and also prevents heat transfer to the caliper and brake fluid when the brakes are worked hard . Others have a stainless metal heat shield to reduce heat flow ( achieved by the drilled holes allowing air-flow over the end of the piston ).
What ’ s a friction rating ? Brake pad material gets rubbed at a certain specified load against a cast iron drum , and the resulting torque is measured . The torque is measured hot and cold , and the friction level determined equates to a letter rating ; A is low friction and H is the highest . Brake pads have two letters on the back that specify the friction level : e . g . a HH pad has the most powerful performance .
Why use steel hoses ? With standard rubber hoses , pressure within the brake system can push outwards causing the hose to swell under heavy braking . Steel hoses are much stiffer , so more of the rider ’ s effort is transferred direct to the caliper . A lot of bikes run the traditional ‘ over the mudguard ’ hose set-up , but this can allow more air in the system and lead to a spongy set-up .
Why can brake levers feel soft / spongy ? The main cause of when a lever feels soft and can be pulled all the way back to the bar without stopping ) is brake fluid fade : brake fluid boils in the system , which produces bubbles . As bubbles are compressible , it is this which makes levers feel spongy . Brake fluid can also go ‘ off ’ just sitting in a brake system , as it ’ s hydroscopic ( can absorb water from the atmosphere , especially in hot or humid conditions ). This is why brake fluid should be changed regularly . Warped backplates can often be a culprit too .
64 KIWI RIDER