The Most Common Shifting Problems and How to Diagnose Them at Home
The drivetrain was working perfectly just a month ago, and now you feel like the chain is playing a guessing game? You click, and it doesn't respond. You shift into gear, and you get a grinding sound instead of a gear shift. It's a classic. Derailleurs, even the best ones, are sensitive to a whole host of small factors: from cable tension, to cassette wear, to a misaligned hanger. The good news: many of these problems can be diagnosed yourself—and often fixed without the need for a service visit. Although sometimes, you know... it's better to just drop in and get it over with.
Specifically about the front/rear derailleur - Adjusting the front derailleur - a guide for cyclists in 2025 - Adjusting the rear derailleur on a bicycle - a guide 2025
The derailleur does not respond to the click
Clicking the shifter but nothing happens? First suspicion: a loose or seized cable. Cables stretch over time, but in older drivetrains, especially those ridden in winter, dirty housing can also be a problem. Water, salt, and dirt get inside, and then even a new cable won't do the trick. Check if the shifter "pulls" – press it and see if the derailleur even budges. If not, you probably have a problem along the way, not at the end. A spray of penetrating cable sealant and a few cable strokes might help. Or... a new cable and housing.
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The chain doesn't stay in one gear
If the chain is skipping a gear, "wobbles" between sprockets, or jumps to one side, the cable tension is usually to blame. The adjustment barrel on the shifter (or derailleur) is your lifeline. Tighten it slightly (increasing tension) or loosen it (reducing) and observe the chain's response. One full rotation of the barrel makes a big difference – work in quarter turns and test patiently.
If the response is delayed in only one direction (e.g., it shifts quickly but is sluggish when disengaging), it's almost certainly due to the barrel or a worn cable. But if the problem occurs in every other gear, the chain jumps erratically – check the cassette wear or chain length.
Worth a look - When and how to replace your bike's chain and cassette? A step-by-step guide.
The derailleur rubs, but the gears work
A common symptom on bikes with a front derailleur. If the chain rubs against the cage in the outer gears, check the L and H screw settings. Set the cranks to the small chainring, the cassette to the largest cog, and check that the derailleur isn't pulling the chain inward. Then shift to the largest front sprocket and the smallest rear sprocket – if the chain "runs away," the H screw needs adjusting.
Properly adjusted limiters eliminate noise and the risk of chain drops. Newer Shimano and SRAM groupsets also offer micro-trim mode, which allows for a gentle "tightening" of the lever without a full click.
Jumping under load
If your chain grinds on climbs or only skips under heavy torque, the problem is most likely a worn cassette or an overly stretched chain. This is a classic symptom that many cyclists ignore until they need to replace their drivetrain.
Check the chain length with a chain gauge (also known as a "gauge"), and if it's above 0.75, it's time for a replacement. Otherwise, the new chain won't be able to connect with the worn sprockets.
See also: The best bike repair shop in Wrocław? 5 reasons to trust us for your drivetrain repair
Derailleur hanger – small but crucial
Sometimes everything looks fine, but something just doesn't click. If the drivetrain works sometimes well, sometimes poorly, and all the bolts and cables are in place, check the derailleur hanger. This small component bends easily—sometimes even after transporting the bike in the trunk.
If the hanger isn't perfectly straight, the derailleur won't be able to align perfectly with the cassette. It's difficult to check this at home without a special tool, but if you feel something's not right, it's best to take your bike to a service center and rule out this issue.
Electronics not responding? That can also be resolved.
If you're riding AXS or Di2 and your derailleur suddenly stops responding, don't panic. In 90% of cases, the culprit is a dead battery (SRAM) or a loose cable connector (Shimano Di2). Check the charging, connections, and cable condition. Make sure the app recognizes the device (for SRAM AXS).
If everything appears connected and the shifting still doesn't work, you may need a system reset or a software update. But in most cases, a new CR2032 battery will return everything to normal.
Gear shifting is like the steering system in a car – even the slightest misalignment and the entire vehicle stops moving properly. Sometimes, turning the barrel a millimeter is enough. Sometimes you need to replace the towbar, cable, and chain. And sometimes… there's simply no point in bothering.
📍 If you're not sure what's wrong, come see us. At Antymateria (Warsaw and Wrocław), we diagnose these kinds of issues every day. No scaremongering, no trickery. We'll simply check what's wrong—and your drive will run like a Swiss watch after an espresso again.
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