Road derailleur cables and housing

How to choose road bike gear cables and housing

Sluggish gear changes are rarely down to the derailleur. In the vast majority of cases, the cable is rubbing or the housing has compressed. The cable is the cheapest part of the drivetrain and delivers the biggest improvement in feel for the money.

Do not confuse them with brake cables

The gear cable is thinner — 1.1 to 1.2 mm versus 1.6 mm — and has a differently shaped head. The housing is different too: gear housing has longitudinal wires, which is incompressible so it does not compress under tension; brake housing has a spiral construction. Swapping them results in vague shifting and spongy braking.

Cable finishes

• Galvanised steel : the most affordable option, but needs replacing more often.
• Stainless steel : corrosion-resistant and a good compromise for year-round riding.
• Coated — Shimano Optislick and Polymer, Jagwire Slick, SRAM SlickWire: the coating reduces friction inside the housing. The difference is clear on frames with sharply curved internal cable routing.

Individually or as a kit

• The cable only is enough when the housing is in good condition — the most common situation.
• A complete kit — cables, housing, end caps and seals — are the way to go when rebuilding a bike or changing handlebars.
• The kits SP41 from Shimano are designed for recent groupsets and include the seals that protect the internal cable routing.
• Keep plenty of end caps end caps to hand: they get crushed during removal and cannot be reused.

Length

Standard cables are 2,100 mm long, enough for the vast majority of frames. Longer 3,000 mm and tandem versions are available for longer frames. Better to trim a cable than find yourself a few centimetres short.

To find out more: How to adjust a road bike rear derailleur

See also: Road rear derailleurs · Road bike brake cables and housing · Road bike drivetrain spare parts