Belfast Bicycles

Cable Maintenance - a diy guide

This article covers regular maintenance of brake and derailer cables, and assumes that the equipment is in good operating condition at the outset. The procedures do not include instructions for replacing or adjusting brake pads, or for adjusting derailer end stops or position. The article is intended for adults with average mechanical ability but assumes no previous bicycle repair experience. Please consult with your local bicycle shop if you have any doubts that the procedures apply to your bicycle or of your ability to carry out the procedures.

Sooner or later all bicycle cables need to be cleaned and lubricated; it makes a lot of sense to do this at the start of each riding season. For casual riding, lubing cables once a year will probably suffice. For off-roading and commuting, clean and lube the cables when they begin to feel gritty. At the same time replace cables that are badly corroded, kinked or frayed, or that are cut too short to be correctly adjusted. We sell excellent quality, teflon coated stainless steel inner wires for many applications for just $5.

In my experience, products that inject lubricant between the inner and outer cables without disassembling the cables do not work well or save time.

Tools & supplies required: Oily lubricant such as FinishLine "Cross Country" chain lube (not a dry lube or wax lube; we sell FinishLine for $6 per 4 oz. bottle), 5mm Allen wrench for most newer bikes (we sell a set for $6), 8 or 9mm box wrench for older and/or less expensive bikes, cable cutters or 8" diagonal cutting pliers, WD-40 spray (use as a cleaner not a lube), cable end crimps (get 5 for a $1).

Procedure: Once you've collected the tools and lubricant and have cleared a work space, you may as well clean and lube all of the cables at once, brake and derailer.

Exposed cables with slotted cable stops

If your cable stops look like this and the cables do not feel especially gritty, the outer casing can be moved to expose the entire inner wire for cleaning and lubing without removing the inner wire from the outer casing. This procedure can be completed in less than half the time of removing the inner wire and requires no tools.

Brake cables - Loosen the cable adjuster to add play to the cable. Apply the brake and hold the brake pads against the rim with your hand. Release the hand brake lever, then pull the outer casing away from the cable stop and guide the inner wire through the slot in the cable stop.

Derailer cables - Do not loosen the derailer cable adjusters. Instead, engage the chain to the largest sprocket (for both front and rear derailers), then move the shifter in the opposite direction while pulling the outer casing away from the cable stop and guide the inner wire through the slot in the cable stop.

Once the cables are released from the stops, clean the exposed inner wire with a WD-40 soaked rag. Then slide the outer casing aside to expose the inner wire that is normally covered. Clean the normally covered section of inner wire and generously lube it with wet chain lube. Reset the outer casing in the stops. To adjust brake and derailer cables, see "Cable adjustment" below.

Covered, trapped or gritty cables

If the outer casing cannot be moved to expose the entire inner wire or if the cable feels very gritty, use this procedure to remove the inner wire from the outer casing.

  1. For derailer cables - first engage the chain on the smallest front and rear sprockets.
  2. Loosen the cable clamp bolt or nut on the brake caliper or derailer and release the inner wire.
  3. Use cutting pliers to cut 1/4" from the loose end of the inner wire; the cut end must be straight and unfrayed.
  4. From the control lever end, pull the inner wire out of the outer casing and control lever. (On some shifters, you must remove an outer cover for access.)
  5. Wipe the inner wire clean. If the cable action felt gritty, use WD-40 with a spray tube to flush the outer casing sections and cable guides.
  6. Lubricate the inner wire with wet chain lube and reinstall it through the control lever, outer casing, cable stops and guides.
  7. Use the flattened section at the loose end of the inner wire as a guide to reattach it to the caliper arm or derailer in the same position as it had been.
  8. To prevent the inner wire from fraying, slip a new crimp fitting to the end of the inner wire and crimp across it twice using the diagonal pliers (do not cut through the crimp).

Cable adjustment

Brake cables

Turn the cable adjuster so that when the brake is applied, the hand lever is approximately 1" from the handlebar grip. If this cannot be achieved, adjust the position of the cable inner wire in the brake caliper clamp.

Derailer cables - for bicycles with indexed shifting

  1. Raise the rear wheel so that it will spin freely when the pedals are cranked, this can be done most easily using a bicycle stand (we sell one for less than $14).
  2. Engage the chain on the smallest front and rear sprockets.
  3. Turn the cable adjusters until the outer cables have a small amount of free play (more than 0 but less than 1/16").
  4. While cranking the pedals at a normal speed, move the shifters to each gear position in succession, and then back again. The chain should engage each sprocket smoothly in both directions.

    Turn the cable adjuster in to add free play if ...

    the chain overshifts (shifts too far) when shifting toward the larger sprockets, or

    the chain engages well when shifting toward each larger sprocket but undershifts (does not shift far enough) when shifting toward the smaller sprockets.

    Turn the cable adjuster out to reduce free play if ...

    the chain undershifts when shifting toward the larger sprockets, or

    the chain engages well when shifting toward each larger sprocket but overshifts when shifting toward smaller sprockets.

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