If your gear cable’s looking a bit rough around the edges, follow these simple steps to replace it and get it set-up sweet.
Undo the derailleur pinch bolt and snip off the cable end. Pull the cable out of the derailleur, through the cable outer and remove the cable entry screw covers on the gear shifters. Shift into the top gear and then push the old cable out.
The new cable will be dry, so take a small amount of fresh grease and put it on a clean cloth. Pinching the cloth where the grease is, pull the new cable through the cloth to ensure that some grease is on the cable. Don’t apply too much.
Insert the non-nipple end of the cable into the shifter and it should pass easily through. When you’re done, pull it to ensure the nipple is fully seated and then try the gear lever to check it’s pulling and releasing cable correctly.
Thread the inner cable through the outer housing. You can usually do this without unhooking the end of the outer from the frame’s cable stops, but occasionally the outer has kinks that mean you need to do the process by eye.
As you work the inner through the outer, it’s possible to accidentally knock the shifter out of gear. Hit the downshift to double check that you’ve selected the right gear – the highest one, and smallest rear cog – before tensioning the cable.
A ‘third hand’-style tensioner is useful for tensioning cable. This pulls the cable out, allowing one-handed fine-tuning while you nip up the anchor bolt with a 5mm Allen key. You’re done when the mech starts to move from its stop.
Once you’re done, run through the gears. SRAM gears are likely to be nigh on perfect, since their 1:1 ratio is more tolerant of issues. Begin in the smallest sprocket and click up one shift at a time. The shifts should be quick and clean.
If you find the derailleur won’t upshift, you’ll need more tension. Wind the adjuster at the gear lever out, exposing more thread. Do this a half turn at a time. If you need to turn the barrel more than twice, readjust the overall cable tension.