by Barry Fraser
The gear system on your bike maximizes your pedalling efficiency. It gives you a mechanical advantage when tackling hills or headwinds and can amplify your power when you want to go all out. But, a skipping chain can kill a climb or ruin a friendly town-line sprint. Poorly tuned gears can rob you of your energy and make a ride tougher. A few simple steps before you head out can ensure your derailleurs are lined up and working as they were designed to.
For a shifting system to function at its best, the components must be clean and properly lubricated. Replace worn or dirty cables. Clean and lube your chain before spending too much time tuning as removing the gunk may be the simple fix for your shifting woes.
Shift into your highest (smallest, outer) cog. Make sure the upper jockey wheel is directly under that cog. If not, there is a small screw called a limit screw on the back of the derailleur marked “H” for “high.” Turn this screw very slightly until the jockey wheel and cog are aligned.
Next, shift into the lowest (largest, inner) cog. Again, the chain should be directly under that cog. Try to over shift with your shifter to see if the derailleur moves past the largest cog toward the spokes. If it does, adjust the L limit screw in, or clockwise, until the jockey wheel is centred. If the chain is unable to climb onto the largest cog, you need to adjust the L limit screw slightly counter-clockwise.
Your next step is the cable adjustment. Shift to the highest gear and check the cable tension. The cable should be under some tension, with no slack. Next, shift into the middle cog. If you clicked the shifter four times, make sure the chain is on the proper cog (fifth highest). If the chain is not on the correct cog, turn your barrel adjuster to get the chain into position. If you need to turn the barrel adjuster more than two full turns counter-clockwise, your initial cable tension was not tight enough. If the chain over shifts onto the next cog, then your cable tension is too high and you need to turn the barrel adjuster clockwise accordingly.
Once this step is done, you should be able to shift through the range of gears without seeing any hesitation or over-shifts. As a general rule, turn the barrel adjuster in the direction you have trouble shifting. If the derailleur is not shifing well into lower gears, it lacks tension, so turn the adjuster counter-clockwise. For trouble shifting into higher gears, turn the adjuster clockwise to reduce some of the tension.
“A few simple steps before you head out can ensure your gears are lined up and working as they were designed to.”
A front derailleur must be aligned properly to be effective. Ensure the outer side of the cage is parallel to the chainrings. Also, make sure the bottom edge of the outer cage sits 2 to 3 mm above the top of the teeth on the big ring.
Once the position is good, shift into the smallest chainring to check your inner limit screw. The inner side of the cage should be close to, but not touching the chain, with about 1 to 2 mm of clearance. Next, make sure there is no excess cable slack. Pull it snug, but not too tight, if required.
Now shift the rear derailleur into the smallest cog and the front derailleur onto the largest chainring. The outer side of the front derailleur cage should be 1 to 2 mm from the chain. If the chain is rubbing the outer cage, try to over shift. If the rubbing stops while doing this action, you need to increase the cable tension by returning to the small chainring and pulling the cable tighter, or by using an in-line barrel adjuster if you have one. If you over shift and the rubbing doesn’t go away, then the outer limit screw is too tight and needs to be loosened (counter-clockwise) until the rubbing stops. If the setup is done correctly, and you have a middle chainring, there should be no need for further adjustment as it will be set from the work you did on the inner and outer chainrings.