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My Rear Derailleur Won’t Shift to the Highest Gear- How Do I Fix It?

My Rear Derailleur Won’t Shift to the Highest Gear

How to Fix a Derailleur that does not Shift to the Highest Gear

Bicycle mechanisms are quite simple to understand. However easy to get as they are, it may have happened to you that you could not fix something that was malfunctioning in your ride.

Fortunately for us, who love doing our repairs on our own, it does not take much research to get to the point and fix it ourselves. In the case of derailleurs, this is no exception to the rule, and when something is not working properly in them, all of our riding gets affected.

How Do Derailleurs Work?

As we mentioned before, understanding how our rides work is not a difficult task to achieve. However, it is of high relevance to know how they do in order to learn to fix them. Derailleurs are not difficult to understand, and before we jump into fixing them, we will give you a little tour of what they do to shift gears.

Derailleurs are in charge of shifting the chain at the rear sprocket. The cage moves inward to move the chain to a different one utilizing a cable. This creates more or less chain tension and causes our pedaling effect to change. When this cable is released, a return spring is in charge of returning the derailleur – and, thus, the chain – back to the previous position or even further.

My Rear Derailleur Won’t Shift to the Highest Gear

Main Causes for a Derailleur Not to Get to the Highest Gear

Whenever we find out that our derailleur is not working properly and cannot shift to the highest gear, the first thing we should do is check the cable. Use a bike stand to help and pedal as you shift gears to the highest gear – in your lever, of course; your bike will not shift.

Once this is done, use your finger to check on how tense the cable is. If the cable is too tight – it will not give in – you have found the source of your problem.

Next, you should check if you can manually force the derailleur to shift to the highest gear. Gently and carefully push it while the chain is moving towards the smallest cog. If it does not work, then the problem is that the screws of the highest shift in your derailleur are too tight.

As a final check, you can look for dents or damages your derailleur may have. These can prevent it from working properly and, thus, not be able to reach the highest shift.

How to Fix a Derailleur that Does Not Shift to the Highest Gear

So, once we have found the source of our problem, we can now go on and fix it ourselves.

This video shows how to repair a derailleur that does not shift to the highest gear(credits to RJ The Bike Guy):

Tackling the first example, if the problem was that the cable was too tight, you need to loosen it up a bit.

To do so, loosen the screw that holds the cable, and let it use some more of it. If, on the other hand, your chain does not shift to the smallest cog when doing it manually, you should look for the screw in charge of that shift – possibly marked with an “H” – and loosen it up a bit, too.

For bent or damaged derailleurs, you should clean up any clogged dirt using a lubricant. After that, you could try adjusting it back into position.

Check for other less common issues that may be affecting your shifts, and see what you need to do to fix it yourself!