If you’re a cyclist, you know that there are a lot of moving parts to your bike. And if one of those parts isn’t working properly, it can make for a very frustrating ride. Case in point: the rear derailleur. This crucial component is responsible for shifting the chain from one sprocket to another, and it’s what allows you to change gears while you’re pedalling.
So what do you do when your rear derailleur stops shifting to the lowest gear? In this blog post, we’ll take a look at some of the most common causes of this problem and how to fix them.
Why Won’t My Rear Derailleur Shift to Lowest Gear? (4 Main Reasons)
There are 4 main reasons that are causing the issue:
1. The Limit Screws Aren’t Set Properly
One of the most common reasons why a rear derailleur won’t shift to the lowest gear is because the limit screws aren’t set properly. The limit screws are responsible for keeping the derailleur from over-shifting, and if they’re not set correctly, the chain can fall off of the sprockets.
To adjust the limit screws, start by putting your bike in its lowest gear. Then, slowly turn each screw until the chain is aligned with the smallest sprocket. Once you’ve done that, pedaling backwards should cause the chain to fall off of the sprocket. If it doesn’t, turn the screws a little bit more until it does.
2. The Derailleur Hanger is Bent
If your bike has been involved in a crash or if it’s been stored improperly, the derailleur hanger can become bent. A bent derailleur hanger will prevent the derailleur from shifting properly, and it’s a problem that can only be fixed by replacing the hanger.
If you suspect that your derailleur hanger is bent, take your bike to a local bike shop and have them take a look at it. They’ll be able to tell you for sure whether or not the hanger needs to be replaced.
3. The Cable Is Stretched or Damaged
Another common reason for shifting problems is a stretched or damaged cable. If your cable is stretched, it will cause your shifters to feel loose and won’t allow the chain to move as smoothly as it should. Likewise, if your cable is damaged, it can prevent the shifters from working altogether.
Fortunately, both of these problems are relatively easy to fix. Start by removing the old cable and replacing it with a new one. If you don’t have a new cable on hand, you can also try adjusting the tension on your existing cable using an Allen key. Just be sure not to adjust it too much—you don’t want the cable to be too tight or too loose.
4. The Derailleur Is Worn Out
Over time, even with proper care and maintenance, your rear derailleur will eventually wear out and need to be replaced. This is especially true if you ride frequently or if you often ride in harsh conditions (like mud or sand).
When this happens, you’ll probably notice that your shifters feel less responsive than they used to and that shifting between gears is becoming more difficult. If this sounds like what’s happening with your bike, then it’s time for a new rear derailleur.
What is the Solution to the Gear Shifting Problems?
There are a few possible solutions:
- A fine-tuning
- Adjust the cable tension: This is the most common solution, and it’s usually done by tightening or loosening the screw on the cable clamp.
- Lubricate the gear shifter: Sometimes the gear shifter can become gummed up with dirt and dust, which can cause problems with shifting. A light coating of lubricant can help to solve this problem.
- Replace the cables: If neither of these solutions fixes the problem, it’s possible that the cables need to be replaced.
Conclusion:
There are a number of reasons why your rear derailleur might not be shifting properly but fortunately, most of them are relatively easy to fix yourself. By troubleshooting common issues like bent limit screws or stretched cables, you should be able to get your bike back up and running in no time at all.
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