How to Fix Bike Gears That Won’t Shift

Bicycles are powered by a manual drivetrain that includes a shifter that controls the cogs, derailleur, and chain. This system is what allows your bike to move and lets you control your bike’s speed.

And how do you do that? Well, by shifting gears.

But what if your gears don’t work properly? And you don’t know what to do to get it back to optimal performance? That’s what this article is about because here, we’ll show you the right way on how to fix and adjust your gears to give you that smooth and lovely ride we all want.

How does gear shifting work?

Every bicycle has a drivetrain that includes a shifter. You can control this shifter by pressing it with your thumb back and forth.

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Every press means that it shifts gear and puts your chain either a step up or a step down through the cogs at the back, with the help of the moving derailleur. All these need to be set and aligned properly for it to work smoothly.

This can be done by adjusting it, or what is more commonly known as indexing. Unfortunately, these gears can easily be out of tune with one another, especially if you have a budget drivetrain. What do you do when this happens? Well, you adjust and index it.

Here’s how.

How to Properly Adjust Bike Gears

Step 1

Slowly move the position of the derailleur so that it won’t let the chain drop at the end-part of the cogs. Then shift the front derailleur into the smallest cog and gently wind the rear adjuster clockwise. Release the bolt of the cable mountain at the rear derailleur.

Step 2

Now that the chain runs on the smallest cog, slowly pull the shifter cable and tighten it using the retention bolt. Double-check your front and rear derailleurs and make sure the gear cables are in the right rear gears. Give it a pedal and slowly push the rear derailleur until the chain goes to the smallest cog. Then stop pedaling. Retighten the retention bolt just enough to secure it in place.

Slowly pedal so that the chain returns to the smallest cog. Test it out by moving the shifter through the cassette.

If it doesn’t smoothly upshift, then increase the cable tension by adjusting the barrel adjuster with a quarter-turn counterclockwise. If it shifts too much, then reduce the cable tension and turn it back clockwise.

If it upshifts smoothly but downshifts slowly, the problem might be because of dirty or damaged inner cables and housing. This is also a common reason why a mountain bike gets a bent derailleur hanger. You can avoid this by lubricating or replacing the cables.

Step 3

Then shift the front derailleur to the smallest cog and the rear derailleur to the middle cog. This slackens the cable and winds the barrel adjuster.

Slowly release the cable retention bolt and remove the slack from the cable. Re-tighten it back using the retention bolt. Then shift to the outer ring. Adjust the barrel adjuster a half counterclockwise turn if shifting is still rough.

You can then repeat this process until the chain smoothly moves through the bigger chainring. Do this to prevent going to the local bike shop just to repair your derailleur hanger. Adjust it until you find the shifting to be in pristine performance.

How to Set Limit Screws

Step 1

Setting limit screws is another important part of being a mountain biker because this is where your pedaling efficiency depends.

The first thing to do for this is to locate the lower limit screw which is usually marked with an L. Then rotate it clockwise. Push the front derailleur and rear derailleur to shift it to the highest gear. Then turn the crank and rotate the low stop screw. This pushes it to the biggest cog.

Step 2

Rotate the high adjuster so the chain can move to the bottom of the cassette. Gently pedal it so that the high adjuster allows the chain to get back to the smallest cog. This should make the gears run smoothly without any clicking or unnecessary jumping.

Step 3

Now is the time to adjust the clearance of your jockey wheel. Locate the screw on the derailleur and put the bike at the highest gear.

The upper jockey wheel will then be near the cassette. Turn it clockwise to increase its gap, or turn it counterclockwise to close it completely. Adjust it until there’s only around 2 mm of clearance between the cogs and upper jockey wheel.

Step 4

Then slowly shift the front gears to the smallest cog, while simultaneously doing this to the back gears and bringing them to the biggest cog.

Wind out the derailleur’s low limit screw until the chain is on the small ring and is running smoothly. It shouldn’t also run with the derailleur cage.

You can also further adjust the derailleur by indexing the barrel adjuster and truing the rear wheel. And you’re all set.

Benefits of Proper Bike Shifting

Speed

Shifting is a huge factor in speed because you can control the maximum speed of your mountain bike. Simply go to the smaller cogs if you want to go faster.

You can then climb steep uphills with ease if you shift to the larger cogs. We recommend 12-speed drivetrains because these are light and capable of XC and downhill rides.

Safety

Having your mountain bike gears shift properly also makes you safe because there is less chance of you falling out of your bike and losing your grip on the pedal just because of an unindexed gear.

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There have been multiple instances where riders crash because their bike didn’t shift to a heavier gear and they put in a lot of pedaling effort.

Convenience

Smooth-shifting lets you enjoy your bike ride because you don’t get annoyed with the unnecessary clunking of gears.

You also don’t have to worry about crashing or not being in tune with your pedaling because of unindexed gear. Proper gear shifting is all about ensuring convenience and making you enjoy your ride.

Conclusion

Knowing how to fix bike gears is an important part of mountain biking. This is where your enjoyment and biking experience depends.

Nothing beats the feeling of shifting smoothly and keeping up to pace with your desired speed. Well, you can achieve that by having a well-indexed and adjusted drivetrain.

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AUTHOR
Jomar Teves
A writer by day, a tech enthusiast by night, and a mountain biker at the weekends. After four years in business school and working for multinational clients, Jomar believes he can improve the world through his writings. Jomar has six years of experience as a writer and has a degree in entrepreneurial marketing. Some of his works have been published on Blokt, Clutch Points, and iTech.