Brake Care Basics - Pt 2
Always ensure that the calliper mounting bolt is long enough. The recessed Allen nut that secures the brake calliper should have at least 8 mm of thread engaged with the calliper mounting bolt. The recessed nut can be obtained in various lengths as required.
Most brakes have a quick release system of some description. Undoing it will provide greater tyre clearance when removing the wheel. It can also be used as an emergency ‘get me home’ solution if you get a badly buckled wheel whilst out on a ride. With a calliper mounted quick release, such as Shimano or SRAM, you will have very poor brake performance when the quick release is undone. Campagnolo’s brake lever mounted quick release makes it difficult to grab the lever but still provides reasonable stopping performance. Only ride with the quick release undone if you absolutely have to and test them first to see how much braking power has been lost.
Never attempt to cut cables with pliers or tin snips—you will wind up with a ragged finish and curse it when you jab your fingers on the frayed ends. Only use proper bicycle cable cutters. They are designed for the task and will last for many years.
Brakes rely on smooth cables to transmit your braking effort through from the lever to the calliper. Good quality cables have a Teflon liner (in the centre of the photo) that sits between the steel inner wire and the metal part of the outer casing. When replacing old cables, you should renew both the inner and outer cable. The friction reducing liner on the outer cable wears with age and should be replaced periodically to ensure good brake performance.
Oil or lightweight grease can help to lower the friction in your brake cables. Some bikes have ‘slotted cable guides’ which make this task much easier. Undo the quick release and hold your brake pads in so they contact the rim. This will slacken your cable tension and allow you to slide the cable out through the slot in the frame mounted guide. You can then slide the cable back and lube it as required.
Always cut off any extra inner cable after the brakes have been set and adjusted. Excessive lengths of inner wire can contact your wheel if they are not cut down. Crimp a cable end onto the inner wire to prevent it from fraying and give your bike a tidy finish.
Heavy braking wears both pad material and the rim surface. The residual mix of alloy and rubber dust can form a glaze on the braking surface of your rims. This can affect your brake performance. Occasional cleaning with a solvent (methylated spirits) and some light emery paper can rejuvenate the braking surface of your rims. Likewise a gentle scrub of the rubber brake pad with sandpaper can clean the glaze off. This does not apply to carbon. You should not attack your carbon fibre rims with emery paper or solvent!
Most brake pads have grooves cut in the pad material. These are designed to allow pad wear material and moisture to escape the rim contact area whilst braking. These grooves should also be used to gauge pad wear (unless the pad has some other form of wear marker). It is time to replace your pads when the friction material is worn to the base of these grooves.