Front Derailleur Installation and Adjustment — Step by Step
The front derailleur has a reputation as the fussiest part of the drivetrain — dropping the chain, rubbing, grinding. In reality it's a simple mechanism, and 90% of problems come down to three things: wrong height, wrong angle, and badly set limit screws. Here's the install and adjustment, step by step.
What you need
Allen keys (usually 5 mm and 2 mm), a Phillips or Allen screwdriver for the L/H limit screws, and optionally cable cutters and a new cable end cap.
Step 1 — cage height
Position the derailleur so the outer cage plate sits 1–3 mm above the teeth of the largest chainring. Too high and the chain will drop and shift slowly; too low and the cage will rub the chainring. Check by sighting down from above the big ring.
Step 2 — angle (parallel alignment)
Viewed from above, the cage must run parallel to the chainrings and the chain. A twisted cage guarantees rubbing and poor shifting. Tighten the clamp only after the angle is set.
Step 3 — low limit screw (L)
Shift the chain to the smallest chainring in front and the largest cog in back. Slacken the cable. Use the L screw to set the inner cage plate about 0.5 mm from the chain — close enough that it doesn't rub, but not so close the chain drops inward.
Step 4 — cable tension
Pull the cable taut by hand and tighten the anchor bolt. Shift the chain onto the largest chainring — if the derailleur won't fully engage, add tension via the barrel adjuster at the shifter (turn counterclockwise).
Step 5 — high limit screw (H)
With the chain on the largest chainring in front and the smallest cog in back, use the H screw to set the outer cage plate about 0.5 mm from the chain — close enough that the chain doesn't overshift off the ring, but engages smoothly.
Step 6 — trim and test ride
Shift through every combination. At extreme cross-chain combinations (big-big, small-small) light rubbing is normal — that's what the shifter's intermediate "trim" clicks are for. Avoid cross-chaining regularly, since it accelerates drivetrain wear.
| Symptom | Cause | Fix |
|---|---|---|
| Chain drops inward | L limit too loose | Tighten the L screw |
| Chain drops off the outside | H limit too loose | Tighten the H screw |
| Won't shift onto the big ring | Not enough cable tension | Add tension / use barrel adjuster |
| Constant rubbing | Wrong angle or height | Redo the clamp alignment |
Bottom line: front derailleur adjustment follows a sequence — height, angle, L limit, cable tension, H limit, trim. Take it one screw at a time. And once the bike's already upside down, it's a good moment to check your chain lubrication schedule too — a clean drivetrain shifts noticeably better.