CoachingAnswer

HOW TO ADJUST BIKE GEARS?

By Anthony WalshRoadman CyclingUpdated 10 July 2026

ANSWER

Gear adjustment on a modern derailleur system involves three components: cable tension, limit screws, and derailleur hanger alignment. Most shifting problems are caused by cable stretch — a quarter turn of the barrel adjuster on the rear derailleur resolves skipping in 80% of cases. If the chain overshifts into the spokes or drops off the small cog, the limit screws (marked H and L) need setting. If the gears are imprecise across the entire cassette despite correct cable tension, the derailleur hanger is likely bent — this requires a shop alignment tool. Electronic groupsets (Shimano Di2, SRAM AXS, Campagnolo EPS) self-index and only require limit screw setup.

KEY TAKEAWAYS

Cable stretch is the most common cause of poor shifting — a quarter turn of the barrel adjuster fixes most skipping.
H and L limit screws prevent the chain from overshifting into the spokes or off the small cog.
A bent derailleur hanger causes imprecise shifting across all gears and requires a shop alignment tool.
Electronic groupsets self-index and rarely need adjustment beyond initial limit screw setup.

WHO THIS IS FOR

IS THIS YOU?

The rider with skipping gears

Your gears shift fine in some positions but skip or hesitate in others, especially under load.

The home mechanic

You want to learn basic gear adjustment so you can fix shifting issues yourself rather than visiting a shop.

The cyclist after a crash or transport

You packed your bike for travel or had a minor crash and now the gears are not shifting properly.

THE ROADMAN VIEW

Gear adjustment is the most common maintenance task that riders feel intimidated by but should not be. In 80% of cases, it is literally one quarter turn of one screw. Cable stretch is natural — it happens to every mechanical drivetrain, especially new ones. When the chain starts skipping or hesitating during shifts, turn the barrel adjuster on the rear derailleur anti-clockwise by a quarter turn and try again. That is it.

The limit screws are your safety net. The H screw stops the chain from dropping off the smallest cog (into the frame). The L screw stops it from going past the largest cog (into the spokes). These should be set once during initial setup and rarely need touching after that. If you have never set them, turn the H screw clockwise until the chain can just reach the smallest cog without overshifting, and do the same with the L screw for the largest cog.

The one job you should leave to a shop is hanger alignment. If you have crashed or dropped the bike on the drive side, the derailleur hanger — the soft aluminium tab that holds the derailleur — may have bent. A bent hanger makes every gear imprecise because the entire derailleur sits at the wrong angle. A shop alignment tool costs under $50 to use and solves the problem in five minutes.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

Calvin JonesDirector of Education, Park Tool
The most common shifting complaint — hesitation when moving to a larger cog — is caused by insufficient cable tension. Cable stretch is an inherent property of steel cables under load and occurs most rapidly in the first 200-500 km after installation. A quarter to half turn of the barrel adjuster anti-clockwise restores correct indexing in the majority of cases.
Shimano Technical TeamComponent manufacturer technical documentation
Limit screw adjustment should be performed with the cable disconnected to set the physical boundaries of derailleur travel independently of cable tension. The H screw is adjusted first so the guide pulley aligns directly below the smallest sprocket, then the L screw so the guide pulley aligns below the largest sprocket. Cable tension is adjusted last to achieve precise indexing between these limits.

PRACTICAL APPLICATION

DO THIS WEEK

Fix skipping with the barrel adjuster
If gears skip when shifting to larger cogs, turn the barrel adjuster anti-clockwise by a quarter turn. If they skip when shifting to smaller cogs, turn clockwise. Test-shift after each quarter turn. Small adjustments make large differences.
Set the H limit screw
Shift to the smallest rear cog. Turn the H screw clockwise until the guide pulley sits directly below the smallest cog. If the chain drops off the small side, the H screw is too loose. If it will not shift into the smallest cog, the H screw is too tight.
Set the L limit screw
Shift to the largest rear cog. Turn the L screw so the guide pulley sits directly below the largest cog without pushing past it. This prevents the chain from going into the spokes — a safety-critical adjustment.
Check for a bent hanger
Look at the rear derailleur from behind the bike. The guide pulley should sit directly below the cassette, perpendicular to the axle. If the derailleur visibly angles inward or outward, the hanger is bent. Take it to a shop for alignment — do not bend it by hand.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

MISTAKEMaking large barrel adjuster changes.
FIXA quarter turn moves the derailleur significantly. Making full turns at a time overshoots the correct position and creates new problems. Adjust in quarter-turn increments and test after each one.
MISTAKEAdjusting limit screws when the real problem is cable tension.
FIXLimit screws set the physical boundaries of derailleur travel. They do not affect indexing between gears. If gears skip in the middle of the cassette, the problem is cable tension, not limit screws.
MISTAKEForcing gears to shift by applying heavy pressure on the lever.
FIXGears that require excessive force to shift have either a cable tension issue, a worn cable, or a bent hanger. Forcing the shift risks dropping the chain or damaging the derailleur.

FAQ

FREQUENTLY ASKED QUESTIONS

Why do new bikes need gear adjustment?

New cables stretch during their first 200-500 km of use. This is normal and expected. Most shops include a free first service at 200-300 km specifically to address cable stretch.

Can I adjust gears without a bike stand?

Yes. Lean the bike against a wall, lift the rear wheel, and pedal by hand while making adjustments. A bike stand makes it easier but is not essential for basic barrel adjuster and limit screw work.

How do I know if I need new cables?

If the outer cable housing is cracked, kinked, or compressed, or if the inner cable is frayed where it exits the housing, replace both cable and housing. Sluggish shifting that does not improve with barrel adjuster changes usually indicates cable friction from wear or contamination.

Do electronic gears need adjustment?

Electronic groupsets (Di2, AXS, EPS) self-index and do not suffer from cable stretch. They occasionally need limit screw adjustment and firmware updates. If electronic gears misshift, the most common cause is a low battery or a bent hanger.

What tools do I need to adjust gears?

For basic adjustment, no tools are required — the barrel adjuster turns by hand. For limit screws, a small Phillips or cross-head screwdriver is needed. For cable replacement, you need a 5 mm Allen key and cable cutters.

Why does my chain drop off when shifting to the small ring?

The front derailleur limit screw (L) is set too loose, allowing the cage to push the chain too far inward. Tighten the L screw clockwise in quarter-turn increments until the chain stays on the small ring without rubbing on the inner cage plate.