How to Adjust Bicycle Gears? | Stop The Skipping And Slipping

Nothing kills a ride faster than a chain that skips or refuses to shift. Most shifting problems boil down to four adjustments on the rear derailleur, plus three for the front. The fix takes about thirty minutes with a Phillips screwdriver, a 5mm Allen key, and maybe a penny.

Work through the steps in this order — hanger alignment first, then limits and tension — because each adjustment builds on the last. Park Tool’s repair guides cover the same sequence their master mechanics use.

Why Hanger Alignment Comes First

A bent derailleur hanger is the most common cause of shifting problems that appear out of nowhere. The hanger is the small aluminum tab that bolts the rear derailleur to the frame; it bends easily when the bike falls over or takes a knock. Even a few millimeters of bend makes the derailleur sit at an angle, so it can never line up with the cogs no matter how you set the screws.

Checking it requires a hanger alignment tool like the Park Tool DAG-2.2, which threads into the derailleur mount and uses a gauge to measure the rim’s position. Per Park Tool’s hanger alignment guide, the job is done with the rear derailleur removed, and the tolerance is forgiving: if three points measured 90 degrees apart are within 3 millimeters of each other, the hanger is straight enough.

If bent, straighten it gently — the tool doubles as the bending lever — then reinstall the derailleur. Every rear adjustment after this must be rechecked, because the new, straight hanger changes all reference positions. Skip this step and you’ll chase a problem that lives in the metal, not the cables.

Rear Derailleur Setup: Limits, Tension, And Indexing

Start with a clean baseline. Shift the front derailleur to the largest chainring and the rear to the smallest cog, then keep clicking the rear shifter until no more clicks remain. This removes all cable slack so adjustments start from a known zero point.

Set the H-limit screw. This screw stops the derailleur from pushing the chain past the smallest cog and into the frame. Back it out a few turns, pedal to confirm the chain shifts outward freely, then use the barrel adjuster on the cable to restore proper shifting.

Index the cable. Pedal at a normal cadence and shift one single indexed click at a time while staying on the rear small cog and an appropriate front ring. If the chain hesitates, turn the barrel adjuster counterclockwise a quarter turn to add tension; if it overshoots, turn it clockwise to release. One click, one cog, no skipping.

Set the B-screw last. The B-screw controls the gap between the top pulley wheel and the cassette. Tighten it to increase the gap, loosen it to decrease. Park Tool’s rear derailleur guide notes that after any major B-screw change, you must recheck indexing — the gap changes the angle of approach and can undo your cable tension work.

If the chain keeps skipping under load after all four steps, the cassette or chain may simply be worn — a mechanical issue no adjustment can fix.

Front Derailleur Setup: Height, Angle, And Cable

The front derailleur has the same limit screws but needs physical positioning before you touch the cable. Two things matter: where the cage sits, and how it angles.

Set the height. The outer cage plate should sit just above the largest chainring, with a 1–2 millimeter gap between the big ring’s teeth and the lower edge of the outer plate. Park Tool’s front derailleur guide confirms this 1–2 mm guideline.

Set the angle. The derailleur cage must sit parallel to the chainring. Viewed from above, the front edge shouldn’t point inward or outward. A quick visual check from the top is usually enough to spot a twisted cage.

Set cable tension. Shift to the innermost rear sprocket and the innermost front chainring. The inner wire should be fairly loose; if taut, use the barrel adjuster to release tension before proceeding.

Set the limit screws. Identify which screw is L and which is H by turning each one and watching the derailleur. The screw that moves the derailleur is the corresponding stop screw. The L screw stops the chain from falling off the small ring toward the frame; the H screw stops it from overshooting the big ring. Adjust each until the chain shifts cleanly without rubbing the cage at either extreme.

Front derailleur setup varies with drivetrain layout. A 2x system starts from a different cable position than a 3x, so follow your drivetrain’s baseline if the steps feel off.

Common Mistakes To Avoid

• Adjusting cable tension before confirming the hanger is straight.
• Turning the wrong limit screw, or moving more than one shift at a time during indexing.
• Skipping the post-adjustment indexing recheck after B-screw changes or hanger correction.
• Setting front derailleur height without the 1–2 mm gap guideline.
• Ignoring the chainring and cassette position when setting front cable tension.

When the system finally shifts cleanly — rear clicks up and down without hesitation, the front drops onto the small ring without drama — the whole bike feels new again. For a gear upgrade or a worn-cassette replacement, our tested roundup of the best bicycle gear can point you toward parts that shift well and hold up under load.