The chain fell off your mountain bike again, didn’t it? You were flying down the trail, standing up to power over some rocks, when suddenly your pedals spun free. Dang it! Now you’re stranded miles from the trailhead with a chain dangling uselessly from your derailleur.
We’ve all been there. A dropped chain can ruin a great ride in an instant. But with the right technique, you can get that chain back on quickly and be on your way again.
In this article, I’ll walk you through the proper way to put a chain back on your mountain bike so you can fix it fast when this inevitable mishap occurs on the trail. With just a few simple steps, you’ll be pedaling again in no time.
Let’s get started and get you back to shredding singletrack!
How Often Should You Replace Your Chain?
The frequency of replacing your mountain bike chain really boils down to two key factors:
- Miles ridden
- Riding conditions
For the average mountain biker putting in 2-3 rides per week, expect to go through at least 2-3 chains per year.
But…that’s assuming relatively dry conditions. If you’re constantly slogging through mud and wet trails, you could easily be replacing chains once a month. The grime accelerates wear.
Full-suspension mountain bikes also tend to devour chains faster than hardtails. All that rear suspension movement puts more tortured stress on chains.
My recommendation is to check chain wear monthly with a gauge tool if you ride frequently. At the first sign of 0.5% elongation, swap that chain out.
Now let’s get to the good stuff – how to actually remove and install a new MTB chain. Grab some lube and tools of your choice, and let’s ride!
Step-by-Step: Removing an Old Chain
Before the new chain goes on, the old one’s gotta come off. Here’s the process:
Things You’ll Need
- Bike chain tool
- Degreaser and rag
- 5mm hex wrench
Step 1: Shift to Small Ring & Cog
Using your shifter, shift the chain into the smallest front chainring. Also, shift into the smallest rear cassette cog.
This gives maximum chain slack to allow removal from the derailleur.
Step 2: Unbolt the Rear Derailleur
Using a 5mm hex wrench, loosen the bolt that attaches the rear derailleur to the hanger bracket.
Rotate it counter-clockwise a few turns until the derailleur is free to swing back.
Step 3: Remove the Chain from the Cassette
With the derailleur unbolted, carefully pull it back and down to loosen the lower portion of the chain.
Lift the top portion of the chain up and over the upper jockey pulley wheel and off the cassette cogs.
Step 4: Break Chain with Chain Tool
Drape the free chain over your chain breaker tool’s spikes. Position a link pin over one of the holes.
Turn the handle to push the chain pin halfway out of the link. Then flex the chain sideways to disconnect.
Step 5: Clean Cassette & Chainrings
Take a few minutes to scrub the cassette and chainrings using a degreaser and a rag.
Remove all old grease and dirt so the new chain runs cleanly.
New chains and dirty drivetrains don’t mix well.
The old chain is now removed. Time to focus on the new one.
Step-by-Step: Installing a New Chain
Here are the key steps to safely install a new chain on your mountain bike:
Things You’ll Need
- New chain
- Chain lube
- Quick connecting link (usually included)
Step 1: Drape Chain Over Cassette
Start by draping the new chain over the smallest rear cog.
Run the chain up through the rear derailleur pulleys.
Step 2: Wrap Chain Over Chainring
Pull the derailleur forward to create slack. Wrap the top portion of the chain over the smallest front chainring.
The ends should meet close to the bottom bracket area.
Step 3: Connect with Quick Link
Most modern chains come with a special quick connecting link.
Push the chain ends together following the manufacturer’s directions to secure.
Step 4: Check Chain Tension
Pedal the crank backwards to shift the chain onto the largest rings front and rear.
Gently pull the derailleur backward to take up excess slack in the chain length.
You want no tight links but also no sagging.
Step 5: Reattach Rear Derailleur
Using the 5mm hex wrench, bolt the top jockey pulley back into place on the rear derailleur hanger.
Snug it down securely but don’t force it.
Step 6: Lubricate Thoroughly
Apply chain lube to all the inner and outer plates and rollers.
Rotate the cranks to work the lube into all the links. Put it in well.
Step 7: Check Shifting
Slowly shift through every gear combination while turning the cranks.
Confirm smooth, crisp shifting performance. Break in the new chain!
The fresh chain is now installed and ready to hit the trails! It wasn’t so bad, right? A little practice, and you’ll be swapping chains in minutes.
Why Do Mountain Bike Chains Need Replacing?
Before we dig into the detail of how to swap out your chain, it’s helpful to understand what causes chains to wear out and need replacement.
There are a few key reasons you’ll find yourself needing to put a new chain on your MTB:
This is the #1 cause of chain replacement. As you ride, chains are pulled back and forth through the gear shifter, slowly stretching out the metal inner links and rollers.
This gradual stretching leads to inaccurate shifting and accelerated wear on cassettes and chainrings. That’s no bueno.
Using a chain checker tool, you can measure the expansion. Once a chain reaches 0.5% stretch or greater, it’s service life is at the end. Time for a new chain.
Pedaling along, and you suddenly feel some resistance or hear a grinding sound? You likely have a stiff link that no longer bends and pivots properly.
Stiff chain links are a reliability issue that can lead to chain breaking. Don’t mess around; just swap out the chain.
Water and mud + lack of lubrication = rust. Unfortunately, mountain biking exposes chains to many elements.
Heavy rust builds up on the links, rollers, and pins hampers on pedaling smoothness and chain strength. A little surface rust is ok, but deep rust requires chain replacement.
Bent or Broken Links
If you inspect your chain and see any bent, damaged, or cracked links, it means game over for that chain.
Attempting repairs will leave you with weakened, dangerous links. Bite the bullet and install a new chain.
Brand New Bike
In another scenario, you’ll need a new chain right out of the box on a brand new bike.
Manufacturers usually include only the bare minimum length chain. Opting for a higher quality chain immediately can improve shifting performance and durability.
Next, let’s go over some pro tips for making your mountain bike chains last longer.
6 Pro Tips to Extend Your Chain’s Life
Chains are a wear and tear item, but you can take steps to maximize chain life between replacements:
1. Keep Your Chain Squeaky Clean
Regular cleaning is a clutch for long chain life. Grit and grime act like sandpaper, accelerating wear.
Give your chain a thorough scrub with degreaser every few rides to avoid build-up. Even a quick wiping with a rag after muddy rides helps too.
2. Lubricate After Every Wet Ride
Lube reduces friction between the chain components. But more importantly, it also displaces moisture inside the links.
Re-apply lube after any wet ride to prevent corrosion and keep things running smoothly.
3. Maintain Proper Chain Tension
Too loose or too tight both negatively impact chain life. Strive to keep chain tension optimized via rear derailleur adjustments.
No sagging, but also no overly tight links. Just right.
4. Avoid Cross-Chaining
Running the chain at extreme diagonal angles between large and small rings causes uneven wear.
Shift wisely and try not to cross-chain in the big-big or small-small gear combos.
5. Replace at 0.5% Stretch
As soon as your chain gauge tool shows 0.5% elongation, replace that chain soon. Don’t try to get out more miles, as it can give you an uncomfortable ride.
Exceeding 0.5% stretch risks damaging cassette and chainring teeth as they mesh with a worn chain.
6. Upgrade Drivetrain Components Together
For optimal shifting performance and reduced wear, replace chains, cassettes, and chainrings around the same time.
Mixing brand new chains with worn cassettes accelerates damage to both. Keep your drivetrain new!
Just remember – chains are a consumable item. Implementing these tips will help maximize longevity, but regular replacement is part of bike maintenance.
Now let’s go over some key indicators that signal your chain is due for replacement.
6 Signs Your Bike Chain is Ready for Replacement
Your chain gauge tool provides the definitive measurement, but there are also symptomatic clues that your chain is ready for a replacement:
- Slipped or skipped shifts
- Grinding noises while pedaling
- Stiff, binding, or squeaky links
- Visibly thinned and elongated links
- Excessively loose links without adjustment
- Oversized rollers or wavy bushings
Addressing worn chains promptly reduces damage to other (more expensive) drivetrain components. Don’t run chains until they snap – stay ahead of the wear.
On that note, let’s cover some common questions about mountain bike chains.
Let’s tackle some frequently asked questions about replacing chains on mountain bikes:
Can I reuse a chain once it’s worn out?
In a word – no. Once a chain is stretched out beyond 0.5% with worn rollers and pins, it’s done. Attempting to extend the life via link swapping just leads to unreliable performance. New chains are cheap – just replace them.
What’s the downside of running a worn chain too long?
Excessively stretched chains accelerate wear and damage on cogs and chainrings as they mesh together. Replacing chains promptly reduces this drivetrain damage. Think of it as preventative maintenance.
What’s the best lube for mountain bike chains?
For wet, muddy, or dusty conditions, a “dry” wax-based chain lube works well. It doesn’t attract grime like wet lubes. Apply after cleaning and work it into the links.
Can I install a new chain on a worn cassette?
Technically you can, but it’s not ideal. The unevenly worn cassette cogs put extra wear on a brand new chain. The best practice is to replace the cassette when you replace the chain.
How do I know which chains are compatible with my bike?
Most modern mountain bikes use standard 1/8” wide chains. Width is the key factor. Nearly any 8-speed, 9-speed, 10-speed, 11-speed, or 12-speed chain will fit. Just match the speeds.
Still have lingering questions? Drop me a comment, and I’ll get back to you!
If you made it this far, it means you now have all the tools and knowledge needed to safely remove and install new chains on your mountain bike.
While replacing a chain may seem daunting at first, it’s one of the easiest drivetrain jobs you can tackle after some practice.
Keep your chain maintenance skills sharp, and you’ll keep your bike shifting smoothly for seasons to come.
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Mahin Abrar is a passionate writer and outdoor enthusiast. As a regular contributor to Bikepics.net, Mahin shares his knowledge and experiences in the fields of biking, cycling, hiking, and camping. With a deep understanding of these activities and a keen eye for detail, he offers valuable insights and practical advice to help readers get the most out of their adventures. Whether you're a seasoned pro or just starting out, Mahin's writing is sure to inspire you and guide you on your journey.