Is there a reason why the range of acceptable indexing varies across gears?

Asked by: James Henderson

What does indexing gears mean?

Today rear gears are ‘indexed’, which means that the shifters can only click into pre-defined positions. Thus modern gears have to be setup far more accurately if they are to work properly and the different parts of the system – sprockets, rear mech and shifter – must be designed to work together.

How do you adjust indexing?

Quote from video: And you can micro adjust it very simply by turning this little dial here which is called the barrel adjuster. And that effectively makes the cable tighter or looser.

Why won’t my front derailleur shift down?

Common Front Derailleur Problems. Front derailleurs may cause sluggish or inaccurate shifting because (A) the derailleur body is not positioned properly, (B) the derailleur limit screws are not adjusted correctly, (C) the mechanism is dirty or (D) the cable is damaged or improperly tensioned.

What do limit screws do?

The main purpose for the limit screw is to prevent the chain from going into the spokes or into the frame. Tightening the H-limit screw restricts the limit as shown.

How do I index my gears?

Quote from video: Simple really your gears are not indexed if the derailleur doesn't fit directly beneath the caucus. And the process of indexing is how you'd correct this problem.

What does L and H mean on derailleur?

You need to adjust the high (H) and low (L) limit screws on the derailleur. Viewed from behind the bike, the H screw limits how far the derailleur can move to the right, while the L screw limits how far the derailleur can move to the left.

Can you change bike gears when stationary?

The changing of gears itself is unlikely to cause any damage, you’re just going to move the derailleurs back and forth until the chain prevents them moving further.

How do you adjust gears on a bike?

If you have trouble shifting as you lower your gears (lower gears are closer to the wheel), then loosen the cable adjuster by turning it counterclockwise. Turn the adjuster slowly, turning until the chain falls into the correct gear. Always work slowly, adjusting by a quarter-turn at a time at most.

How do you calibrate a derailleur?

Quote from video: Set to increase this gap tighten the B screw. To decrease the gap loosen the B screw. If you made significant changes to the B screw double check the indexing adjustment.

What happens if front derailleur is too high?

Derailleur Alignment & Positioning



Most front derailleurs can be adjusted for height and rotation. If the cage is set too high over the largest ring, it may not perform well. Too high a cage can cause a slow shift, and can allow the chain to shift over the largest ring.

How tight should front derailleur cable be?

It is generally a good idea to lubricate the pivot point of the front derailleur with a light lubricant. The cable inner wires should also be lubricated. If you have loosen the inner wire pinch bolt, lubricate those threads as well. When tightening this pinch bolt, secure to approximately 30-40 inch-pounds.

How high should my front derailleur?

Quote from video: The height should be checked with the lower edge of the outer cage. Directly over the largest ring here we'll pull the shifter or cable to line up these two planes.

Why does my chain slip under pressure?

These include worn out or misaligned derailleur pulleys, old or malfunctioning shifters throwing off the indexing in some gears, or broken/bent teeth on one or more cassette cogs. Build up of dirt and grime on drivetrain components will also cause shifting issues, including skipping chains.

Why is my derailleur loose?

Likely the issue is either a bent derailleur hanger or the low limit screw needs to be adjusted. First, try to wiggle the cassette, then the derailleur and hanger to make sure everything is tight.

Why is my derailleur clicking?

If you hear a constant clicking (especially in certain gears), it could mean that your shifter cables have stretched enough to pull your derailleur out of alignment, causing your chain to ride between gears or rub on the derailleur cage. First, make sure your derailleur is aligned and that the hanger isn’t bent.

How do you index a front derailleur?

Quote from video: Front indexing in a nutshell there's two things to remember firstly. The limit screws. Just how far the derailleur can move either out or in but to actually control the movement of the derailleur.

How do I reindex my mountain bike gear?

Quote from video: So I'm going to give that barrel just a half turn anti-clockwise to put more tension on that cable.

How do you calibrate a derailleur?

Quote from video: Set to increase this gap tighten the B screw. To decrease the gap loosen the B screw. If you made significant changes to the B screw double check the indexing adjustment.

How do I stop my bike chain from rubbing on the front derailleur?

If the chain is rubbing the outer edge of the derailleur cage, try increasing the cable tension using the barrel adjuster by turning it counterclockwise one quarter to one half turn at a time—increasing the tension will pull the cage out and farther away from the bike.

What happens if front derailleur is too high?

Derailleur Alignment & Positioning



Most front derailleurs can be adjusted for height and rotation. If the cage is set too high over the largest ring, it may not perform well. Too high a cage can cause a slow shift, and can allow the chain to shift over the largest ring.

How tight should shifting cable be?

Quote from video: The bolt that crimps your cable tight and pull that slack tight with your hand or with a pair of pliers not too tight you don't really need to wrench.