In this guide, nosotros'll explicate how to conform and alphabetize your front and rear derailleurs to fix your shifting, as well as demonstrate how to diagnose and fix common shifting problems with your bike gears.

A silent and polish-running transmission tin make all the difference to your ride and fixing your bike'southward gears is something that fifty-fifty the nearly mechanically inexperienced can handle.

How to diagnose common drivetrain issues

The first thing to exercise is to find out what'southward actually wrong with your gears.

Problem: Gears won't shift upward or down perfectly with 1 click

• Solution: This is most commonly caused by stretched gear cables and you will demand to re-index your gears.

Problem: Gears are well indexed but the chain keeps dropping off of either finish of the cassette or chainrings

• Solution: This is most commonly caused past poorly prepare derailleur limit screws and these volition crave adjusting. It tin can besides exist caused by a bent derailleur hanger.

Problem: My rear gears are properly indexed, but the chain shifts likewise far in i direction

• Solution: If the chain won't run to the bottom of the cassette and shifts over the big cog into the spokes (or vice-versa), information technology sounds like a aptitude rear hanger needs straightening or replacing. If you've been in a crash or damaged the wheel somehow, this is the likely cause. It is as well possible, but less probable, that the limit screws are causing this.

Trouble: Downwardly-shifting is fine but upshifting is pasty or dull

• Solution: When were your cables last replaced? Muddied cables and housing tin crusade slow or inaccurate shifting.

Problem: Chain slipping, jumping and generally misbehaving

• Solution: Audit your cassette, chain and chainrings for habiliment. Can yous run into a pointy shark-fin-like profile on your cog teeth or chainrings? Nosotros're distressing to say, but that sounds like yous may need to supersede your chain, cassette and chainrings.

How to index the gears on your bicycle

If the gears on your bike are properly indexed, each single click of the shifter will cause a single shift up or down the gears, front end or rear. If you find y'all're skipping a gear or that your shifting is getting stuck, then there'southward a good adventure you lot need to adjust your indexing.

Indexing bug can be caused by cable stretch, which is a normal role of the bedding-in process for new bikes or cables.

Check that a aptitude or damaged rear derailleur isn't to blame first. If information technology's all proficient, here's how to index or re-alphabetize your gears.

What you need

• A hex key to fit your derailleur cable memory bolt, unremarkably a size 4mm or 5mm

How to index wheel gears

Stride 1

Carefully and slowly move the derailleur manually to make sure it won't allow the chain to drop off either end of the cassette

Shift your forepart derailleur into the middle or smallest ring, and then air current your rear butt adjuster in fully clockwise, then out one turn. Release the cable mounting commodities on the back of the derailleur.

Step 2

Pedal gently and push the derailleur until the chain moves up to the second-smallest cog, then stop pedalling. Pull the shifter cablevision taut and retighten the memory commodities, taking care non to overtighten it, which can crusade the cablevision to fray.

Pedal gently and the concatenation should render to the smallest cog, then exam the indexing by using the shifter to move through the cassette.

If upshifting is hesitant, gradually increase cable tension past turning the barrel adjuster a quarter plow anticlockwise and trying over again. If your bike over-shifts, reduce the cable tension by turning your barrel adjuster clockwise until the concatenation runs smoothly in the second smallest cog.

If upshifting is responsive, but downshifting isn't, then at that place'southward a high chance the problem is dirty inner cables or housing, in which case you lot should try lubricating them or replacing them.

Adjust your cable tension using your barrel adjuster until the concatenation runs smoothly in the 2nd smallest cog

Step iii

Shift your front derailleur to the smallest band and your rear to a cog near the middle of the cassette and so slacken the front end derailleur cablevision by winding the barrel adjuster fully clockwise.

The barrel adjust will either exist at the shifter, inline on the cable or, if information technology's a modern front derailleur, one of the bolts on the derailleur itself.

Release the cablevision retention commodities, take any slack out of the cable and so re-tighten the cable retention commodities.

Attempt to shift to the eye or outer ring. If shifting is hesitant, current of air the butt adjuster i half plow anticlockwise earlier pedalling once more.

Repeat this process until the concatenation steps upwardly cleanly onto the bigger ring. If you accept a third chainring, try upshifting to it and add another half turn if shifting is withal hesitant.

Once you're happy with your upshifting, drop back downwards through the rings to check your downshifts.

Setting derailleur limit screws

Limit screws control the range of movement of a derailleur. If they're not set properly, then your concatenation may be able to driblet from the cassette or chainrings, which can be unsafe – for both you and your cycle.

Earlier getting started, ensure your derailleur hanger hasn't been bent. If it is, you'll need to fix or replace information technology.

What you need

• A small crosshead screwdriver or hex key

How to prepare derailleur limit screws

Step 1

Push on the derailleur to manually shift up to the highest gear possible – this should take you to the second or third biggest band on the cassette.

While still manually pressing on the derailleur, gently turn the cranks and wind out the low stop screw until the cassette shifts to the biggest cog and isn't jumping or clicking.

Step ii

Wind out the loftier (H) adjuster and allow the chain to move towards the bottom of the cassette by pedalling gently.

Current of air in the high adjuster until the concatenation returns to the smallest ring/highest gear and runs smoothly without jumping or clicking.

Your rear loftier and low limits should now be set.

Step 3

Adapt your jockey-bike clearance by locating the spiral on the height-rear of the derailleur. This adjustment is referred to as the B-tension or 'dangle-angle'.

With the bike in the highest gear, the upper jockey bike should run just clear of the cassette. Turning clockwise volition increase the gap, anti-clockwise will close it.

Arrange until there is about 2mm of clearance betwixt the cassette and the upper jockey wheel.

Step four

Shift the forepart gears to the smallest band and the back gears to the largest cog. Fully wind in the front derailleur'south low limit (50) adjustment screw.

You should complete this procedure with a slack gear cable, so you can exist sure that cable tension isn't overriding your low limit setting.

To do this, release the cable retention bolt on the derailleur. Slowly plough the pedals and current of air out the screw until the concatenation returns to the modest ring and runs smoothly, without rubbing on the derailleur cage.

Pull the slack from the cable and re-tighten the retention bolt, not then tightly that you fray the cable. Wind in the high limit (H) cease spiral. Shift the rear gears to the smallest cog.

Pull on the gear cable manually, non with the shifter. You can use a tyre lever to pull on the cablevision so that it doesn't dig into your hand.

Keeping pressure on the cable, current of air out the screw a half turn at a time until the chain jumps to the biggest ring. After this, quarter turns volition allow you to adjust the derailleur and then it doesn't rub the chain.

Your high and depression stops are now set, but you will probably need to make adjustments to your front end indexing using the barrel adjuster.

Replacing a aptitude rear derailleur hanger

Derailleur hangers are sacrificial parts that are specifically designed to bend or break in the outcome of an impact to prevent more costly harm to your derailleur or frame.

If your rear shifting isn't working properly and your bike has suffered a knock – in a crash or while loading into a auto, for instance – then there'due south a good hazard your hanger is bent.

Bending a hanger is easily done, which is why nosotros'd recommend always carrying a spare with you on the road or trail, too as a multi-tool with the right size hex keys.

Any hanger volition work with any derailleur, but y'all might need to do some inquiry to find i that is compatible with your frame.

Don't exist tempted to try to bend your hanger back to shape during a ride because it's likely to break, leaving you with a long walk domicile.

Instead, you could try readjusting your rear derailleur limits and indexing, by following the videos above, to compensate for the misalignment. This might not requite you access to your whole cassette, but information technology'll get you dwelling.

Bold you have a spare to hand, here's how to install it.

For the more mechanically inclined, it is possible to straighten a hanger just should but be washed with the correct tools and the knowledge of how to use them properly.

What you lot need

• Multi-tool
• Appropriately sized hex keys
• A new hanger

How to supersede a bent derailleur hanger

Footstep 1

From behind the cycle, sight the line of the chain as it runs over the cassette and through the upper and lower jockey wheels.

All 3 should be bundled in a straight line, and if they're not, you're going to have to become alee and supplant the hanger.

Bends towards the cycle are the most common, though outward misalignment is possible too.

Footstep 2

Remove your rear wheel. And then remove the derailleur from the hanger, assuasive it to remainder on the concatenation.

Pace three

Next, undo any bolts connecting the hanger to the frame, taking care not to lose them.

Reverse this procedure to fit your new hanger, rapidly check your limits and indexing, and y'all're ready to ride.