So, you’re looking to do a mountain bike to gravel bike conversion.
If you’re looking to get into the exciting new off-road discipline of gravel, but don’t want to break the bank buying another bike, learning how to convert a mountain bike to a gravel bike could be your best bet.
This process is a little technical, but with this straightforward guide, you’ll have your MTB to gravel bike conversion done stress-free. We’ll take you through the 10 steps.
Read on, because in this article we’ll be covering:
- The Differences Between A Mountain Bike And A Gravel Bike
- How To Convert A Mountain Bike To A Gravel Bike In 10 Steps
- Why Do A Mountain Bike To Gravel Bike Conversion?
Let’s dive into how to convert a mountain bike to a gravel bike!
The Differences Between A Mountain Bike And A Gravel Bike
- Check out our Complete Mountain Bike Vs Gravel Bike Guide here!
Mountain biking and gravel biking have plenty of similarities, but are essentially different off-road disciplines.
Gravel biking refers to riding over all sorts of relatively mild, unpaved terrain at speed: gravel, single track, and anything else. It has more in common with cyclocross than mountain biking.
Mountain biking generally means tackling uneven, pitched off-road terrain, including sharp ascents and gut-wrenching downhill drops.
Though any labels for cycling styles are subjective, the design of mountain bikes vs gravel bikes reflects these differences.
Though there’s a broad spectrum of gravel bikes, they actually tend to have more in common with road bikes than mountain bikes. If you’re starting with a mountain bike frame, though, yours will end up a little further to that side.
- Check out our Ultimate Guide to Converting a Road Bike To a Gravel Bike here!
So a successful mountain bike to gravel bike conversion will mean bridging the gap between the different designs as best you can.
For your MTB to gravel bike conversion, the parts you’re most likely to want to change are:
- Wheels
- Tires
- Handlebars
- Cassette (optional)
- Chainring (optional)
Thankfully, the two designs do have enough in common that you won’t need to change everything.
The frame, suspension, disk brakes, pedals, and crank can all stay. When it comes to your drivetrain, that’s up to you – some mountain bike drivetrains are perfectly suitable for gravel too, whereas others won’t quite cut it.
How To Convert A Mountain Bike To A Gravel Bike In 10 Steps
#1: Take The Mountain Bike Apart
Start by stripping off any parts you’re not planning on keeping.
It’s true, some of the parts will be going back on just as before, but it’s better to have everything clear and to build back up from scratch.
You’ll need:
- Bike stand
- Allen keys
- Screwdriver
- Cassette tool
- Chain breaking tool
- Torque wrench
We’d recommend leaving your bottom bracket in, as long as it doesn’t need replacing.
Gravel cycling can be a bumpy ride, but if you’re happy with your mountain bike’s saddle and seat post then they can be left alone too.
This is also a good opportunity to give the frame and individual parts a good clean. Grease, grime, and debris should lift off nicely with hot soapy water and a brush.
With proper care and attention, your mountain bike to gravel bike conversion can feel like a shiny new bike!
#2: Wheels
Large 29-inch wheels (700c) typical of road bikes and some modern mountain bikes are popular for gravel biking. Smaller 650b wheels also work well.
Swapping your wheels basically depends on your frame’s clearance. You need the wheel to be able to run with a thick tire and tread.
You may not feel the need to change your wheels if they’re already a suitable size, but you might want to swap them out for something a little more speed-oriented when switching from MTB to gravel bike.
You will, however, need to take the wheels off to fit the new cassette if you’re changing it, and to change the tires.
If you’re going to be using rim brakes for this build, take the time now to give the brake track a good clean too.
#3: Change The Tires
Tubeless tires are a great choice for gravel, as they’re less puncture-prone than clinchers.
You’ll want an aggressive tread for traction, without sacrificing too much in terms of rolling resistance for speed. So, look into tubeless tires specifically for gravel cycling.
You’ll need to make sure your rims are tubeless-compatible too if you’re planning on making the switch.
#4: Cassette (Optional)
Next, it’s time to fit the cassette to the rear wheel. You’ll want something nice and big for a wide gear range and low gear ratios for gravel bikes.
This is especially true if you’re running a 1x chainring, often recommended for off-road cycling.
Align the cassette sprockets and fix them in place with the lockring.
- Check out our Gravel Bike Groupset Guide here.
#5: Chainring (Optional)
For a single chainring at the front, a moderately large 40t ring is often a good choice for gravel biking.
2x chainrings will be a little better suited to cycling at a consistent speed but bear in mind it will require that you fit a front derailleur, which the original mountain bike may not have.
It’s probably easiest to just go with whichever chainring setup your mountain bike already has.
#6: Derailleurs And Chain
Find yourself a dedicated clutched gravel bike derailleur for this build to give your chain a nice amount of tension over the gravelly bumps and wobbles.
Screw your derailleur into the frame’s hanger using an Allen key.
If you’re running a 2x crankset and your frame doesn’t already have a front derailleur hanger, you can buy mounts that do the job.
With your derailleur(s) and wheels on, it’s time to refit your chain.
Whether your chain needs replacing will depend on whether you’ve made any changes to the rest of your drivetrain – and how worn your original chain was.
- Check our guide to Replacing a Bike Chain here.
To do this, thread one end of the chain over both the cassette and chainring, as well as through the derailleurs, bringing both ends to meet below.
Finally, rejoin the chain and turn on the clutch on the rear derailleur.
#7: Pedals
With the crankset on, you can fit your pedals. Two-bolt SPD cleats are ideal and are possibly what the mountain bike is already fitted with.
Whilst a favorite for road cycling, three-bolt cleats such as SPD-SLs aren’t ideal for gravel. They clip into a plastic platform on the sole of your cycling shoe which will quickly wear down and make stepping off the bike difficult and awkward off-road.
#8: Handlebars and Stem
Next, you’re going to want to do away with your mountain bike handlebars in favor of gravel bike handlebars.
Start by changing your stem.
Mountain bikes typically use short stems to take on sharply pitched terrain, but you shouldn’t need this out on gravel, so you can afford something slightly longer for better aerodynamics.
Mountain bike stems have typical lengths of around 35 mm to 80 mm, while road bike stems are usually between 90 mm and 140 mm. For gravel, you’ll want to meet somewhere in the middle: generally between 80 mm and 100 mm.
For gravel biking, your best bet is the flared drop handlebar.
These give you the aerodynamic gains of road bike drops, while the flares and extra width give you a balance of control and speed off-road.
Cyclocross handlebars would also be fine, the two designs do have a fair amount in common after all.
#9: Brakes
With your gravel bike handlebars fitted you can start by connecting up your brakes.
As mentioned, disk brakes are preferable. Their modulated braking offers better control and they’re less prone to being clogged with debris.
However, you’ll also need to have a frame and wheels that are disc-brake compatible if you want to use them.
Unlike downhill mountain biking, where disks are a must for your safety due to extended periods of heavy braking, rim brakes can also work ok on gravel too if discs aren’t an option.
Just make sure you take care of them and keep the brake track clean!
#10: Gear Shifter
Last of all you need to fit your gear shifters.
If you’ve switched from flat handlebars to drops, you’ll need to replace your shifters to be compatible.
Thread shift cables through the bike’s cable housing to link the gear levers and derailleurs. With the components hooked up, retape the handlebars, give the bike a thorough check-over to ensure it’s all set up correctly and safely, and you’re good to go!
Why Do A Mountain Bike To Gravel Bike Conversion?
These types of conversion jobs aren’t straightforward, and you may be left wondering why we bother at all.
As we all know, buying new bikes is costly and they take up space, so a mountain bike to gravel bike conversion is a solid way to get onto the gravel.
And it can be hugely exciting to get to know your gear intimately with a full-on bike overhaul like this.
After a mountain bike to gravel bike conversion you’ll know every inch of your bike, and picked out a number of the parts yourself.
And now you know exactly how to convert a mountain bike to a gravel bike you can make it happen!
