Of all the possible issues that could occur when out for a ride, anything to do with the drivetrain tends to terrify cyclists the most.
A flat tyre is easy enough to diagnose and fix, but what happens when it comes to your bike chain skipping between gears while you’re riding, or shifting twice instead of once when you try to change gears when pedalling hard?
Well, this problem is annoying as it will usually occur when you need good gearing the most; like when you are pedalling hard uphill or taking off, however it is not hard to fix.
Why Does My Bike Chain Skip When Pedaling Hard?
There are many scenarios in which your bike chain skips when pedaling hard, and it is up to you to funnel through the most relevant scenario to diagnose the problem with your bike. The first and most common scenario happens due to the natural stretching of cables that comes with usage.
You should not be alarmed at this, the most stretching happens within the first few times one rides a new cable. However, if a cable is old it can stretch too much, which in turn means that your cable doesn’t have enough tension to regulate derailleurs.
In plain English the component that precisely places the chain from one sprocket to another according to what gear you are in will be wonky and miss gears, double shift etc.
To fix this issue, you may need to repeat this process separately on each derailleur. The process is the same, the only difference being the direction in which you add tension to the barrel adjuster.
First, you need to place your chain on the lowest cog, and press the shifter up to see if the bike changes up a gear. If not, its’s time to add more tension. First, locate the barrel adjuster, which is usually located on your brake, with the brake cable running through it before going into the shifter.
Once it is located, to adjust simply turn it half a turn away from you (rear derailleur) or towards you (front derailleur). Once it’s been adjusted, shift into the lowest gear/cog again, and see how it shifts.
If it performs properly the first time round, you are done and very lucky. If not, rinse and repeat the process, adjusting the barrel adjuster until your gears are shifting smoothly and consistently.
This is the most common cause and fix of the problem. If this doesn’t work, the most advisable thing to do would be contact a mechanic, however there are a few simple scenarios and some other issues worth at least being knowledgeable of, if not possessing the skills to fix.
If Your Bike Chain Keeps Falling Off
It is possible that your chain was either too stretched or long to begin with, which may make it fall off altogether. In the latter case, removing a few links may help your chain be at the optimal tension. In the former case, you may want to consider replacing the chain altogether, because just like most moving bike parts it is consumable and wears down over time.
If this isn’t an option, and adding tension didn’t do anything, it is good to analyse the state of your cables. Sometimes, cables can have difficulty moving through the cable housing due to simple rust and corrosion that has built up over time. In this case, pull your chain off and douse it in some chain oil. This is a very temporary fix but will get your bike moving in a pinch.
Are Your Derailleurs Bent?
Also check for bent derailleurs, derailleur hangers, and finally bent teeth on a cog. Unfortunately, all of these except derailleur hangers can be straightened out, and if it is these they most probably need to be replaced.
This bending is most common for MTB riders due to the heavy impact, yet few riders look at their bike closely enough to even recognize these issues.
Bigger Issues To Consider With Bike Chain Slip
Now, a bigger problem in terms of bike chain slip is when the chain starts skipping over actual teeth. The pedals will start to fall and become useless when they have pressure applied on them, making it impossible to ride uphill and what’s worse is that you might even get hurt or fall down from the bike if unaware of the problem or you leave it.
The biggest cause, is a worn-out chain or cogs. As I mentioned, all moving bike components are consumable and have a limited mileage. Each and every link on a chin rotates and eats away at itself, which eventually adds length to your chain, causing it to sit poorly on the chainring. This can be slowed down by regular maintenance like oiling and cleaning.
Same applies to the cogs in terms of how they are slowly worn down and can be maintained. Other issues that will cause bike chain slip over teeth include: stuck chain links, a chain that is too long, wrong chain link width, and in rare cases freehub skipping.
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Now you are equipped with some scenarios that would cause bike chain slip and for them to skip, whether that be gears when shifting or over teeth themselves.
In most cases, you’ll have luck with simply adding tension to you cable, but if the problem lies within your chain, derailleurs or cogs, just remember all moving parts need to be properly maintained and looked after to slow down their eventual wear and replacement.