Depending on what you’re looking to get out of a bike, there are clear advantages and disadvantages to choosing a mountain bike over a gravel bike. Thanks to an explosion in this space, you may also see gravel bikes referred to as adventure or all-terrain bikes. They’re really toted as the modern “do it all” bike.
In most cases, people are trying to pick between a mountain and gravel bike because they can only afford one bike and need it to fit the widest range of needs.
Because the range of needs can be so wide, it’s easy to see why the choice can be a tough one. You want to be able to ride into town, put in a few hours of exercise on smooth gravel or dirt roads, and potentially tackle some offroading.
While there isn’t a single answer for everyone, a hardtail mountain bike is the best all-around bike. It’s better suited to handle the widest range of conditions and can be easily modified to improve its performance on smooth dirt or gravel roads.
Instead of just taking my word for it, I’ll walk through the advantages and disadvantages of a mountain bike for smooth gravel or dirt roads and let you make your own decision.
Advantages of Mountain Bikes for Gravel Riding
Advantage #1 – Durability for tough conditions
Even when sticking to gravel, dirt, or fire roads the conditions can get hairy at times. In these situations, a mountain bike will have a clear advantage thanks to its front suspension fork and larger tires.
Whether it be hitting potholes or hopping over jumping rocks or roots a front suspension can make a world of difference.
The same goes for larger tires. Their increased surface area allows them to roll over obstacles like the aforementioned rocks and roots, while also avoiding flats.
Mountain bike tires also have more tread that will provide better grip in wet or muddy conditions.
Advantage #2 – Versatility
Mountain bikes, especially hardtails, provide a high degree of versatility. They make transitioning from the street to the trail very easy.
Lock out the suspension for smooth or paved roads to make a commute to work or the trail more efficient.
Once arriving at the trail, you’re literally a quick switch away from unlocking hours of singletrack fun! While a gravel bike would surely be able to get you to the same trailhead, it’s not going to be a fun experience trying to ride one on true singletrack.
In fact, you’d most likely end up needing to walk the bike home thanks to the inevitable flats that would occur.
Advantage #3 – Gravel race training
While it might sound counterintuitive, a hardtail mountain bike can be a great tool to train for gravel races.
Its increased rolling resistance and lower aerodynamic profile are the equivalents of adding more weight to the bar in the gym. Rides will be more demanding and force your body to get stronger and adapt.
As the race gets close you can swap back in a true gravel bike, or make some enhancements to your hardtail to make it more efficient. You should feel like a million bucks cruising down the road with most of that resistance removed.
Disadvantages of Mountain Bikes for Gravel Riding
Disadvantage #1 – Limited hand positions
Just looking at gravel bikes one of the most obvious differences is their use of drop handlebars. These are in place for a good reason because they provide a variety of positions for the rider to place their hands.
Over long, multi-hour rides this is very important to allow the rider room to move around and maintain their comfort.
By comparison, mountain bikes use wide flat handlebars. While these are fantastic for allowing for a more upright riding position and better maneuvering, they won’t be as comfortable for long races.
You’re basically limited to moving your hands wider or narrower but always stuck in a pronated position.
Comparatively, drop handlebars let you transition your arms to a variety of grips that can help to both prevent and ease nerve pain in the hands and arms. Drop handlebars can also help to optimize your profile which leads to the next point…
Disadvantage #2 – Lack of aerodynamic design
Mountain bikes are built to maximize a rider’s ability to see and react to situations. Because many of these situations involve downhill or slower speeds, aerodynamics are less important. However, when you talk about cruising down a dirt or gravel road the speeds can be much higher.
As the speed increases, so does the need for an aerodynamic profile. When considering hills, it wouldn’t be a surprise that you couldn’t reach a speed of in the high twenties or even low thirty miles per hour.
At this point, reducing your aerodynamic profile can make a big difference.
To put some real numbers behind it, Outside Online estimates that a mountain bike creates 5,000 grams of drag. A gravel bike on the other hand only creates 3,500 grams of drag. That’s 35% less drag! Talk about a big improvement.
Much of this improvement comes from the ability to lower your profile by falling into the drops and reducing your body’s surface area. Aside from the variety of hand positions, this is yet another reason why drop handlebars are useful for gravel rides.
Disadvantage #3 – Limited gear range
I won’t say all, but many of the modern mountain bikes being produced today have a single front chainring. These one-by drivetrains have grown in popularity for mountain biking because they lower the bike’s weight and reduce the number of moving parts for potential failure.
This means that your potential gear range is determined solely by your cassette. Cassettes often run 1×10, 1×11, in 1×12 cog arrangements. With common gear ranges including 11-42T, 10-42T, and 10-50T.
While having big jumps between cogs is helpful for rapid shifts in mountain biking, it makes finding just the right gear for tempo rides on gravel roads tricky at times.
The perfect gear for your ride could very well exist between two of your available cogs, so you’re forced to spin a little faster or push a little harder than normal to make it work.
When hitting high speeds on downhills you also may not have enough gears to maximize your speed. When it comes to racing or group rides, not being able to maximize your speed on downhills is a quick way to lose time or hold the group back.
Referred to as “spinning out”, this essentially means that you could go faster but are limited by your gears.
Disadvantage #4 – Bigger tires
While a mountain bikes big tires are a big advantage for off-roading, they’re less than optimal on smooth dirt or gravel roads. Their increased width and additional tread create more rolling resistance over the ground.
Like was the case for aerodynamics, this makes for a less efficient setup compared to using thinner tires with less tread as are found on gravel bikes.
The good news is that there’s an easy way to fix this, as we’ll get into shortly!
Disadvantage #5 – Heavier weight
Thanks to it’s more robust frame and other components, mountain bikes are generally heavier than gravel bikes. While weight generally isn’t a big deal in mountain biking, it could certainly make a difference in gravel racing.
Each additional bit of weight requires your body to produce more force to move the bike the same distance. This is clearly the less efficient option compared to racing lighter weight gravel bikes.
How to Maximize a Mountain Bike for Gravel Roads
Now I know what you’re probably thinking at this point. How could a mountain bike be the better choice with more disadvantages than advantages?
Well, if you can only have one bike, the reason I lean towards a mountain bike is that you can quickly “fix” many of its downsides.
With just a few quick changes you can optimize a mountain bike for gravel riding. So, let’s take a look at them!
- Bike selection – A hardtail 29er is going to be the closest to a gravel bike, while also offering the benefits of a true mountain bike. Full suspension bikes can be used as well, but could add weight (and price) and would need to offer the ability to lock out the rear suspension to avoid energy loss in flat areas.
- Pick a bike that has a 2x system – Due to the limitations of 1x systems for finding the perfect gear on tempo rides and avoiding spinning out, a 2x system will be a better fit. They only increase the bike weight by a small amount but provide you with more options.
While you can certainly upgrade a bike’s drivetrain from a single front chainring to two, it will be much cheaper to simply buy a bike that has one in the first place. If need be, you could even negotiate with the shop when purchasing the bike to take care of the conversion for you.
- Swap our your tires – To reduce the bike’s rolling friction you should definitely consider swapping out the tires. Opt for tires that are both narrower and have less tread to help you ride more efficiently. A pair of cyclocross tires could be a great fit.
If you do plan on switching between gravel and singletrack often, it could even be worth have two wheelsets to make the swapping easier. Leading tire manufacturers like Maxxis even make gravel-specific tires like the Rambler which has a tread that’s optimized for gravel riding.
- Consider adding
bar ends– In order to maximize your aerodynamics, it may be worth installing a set of bar ends. This way you can take full advantage of both the enhanced aerodynamics as well as the comfort of having additional hand positions. This set of bar ends on Amazon offers great value!
- Install narrower handlebars – The average mountain bike comes with ~760 – 780 mm handlebars. While these wide handlebars are great for maneuvering on the trail, they don’t help from an aerodynamic standpoint. To solve this, you may want to consider installing a narrower set of handlebars or even cutting down your current ones.
Somewhere in the 730 mm range is probably a good fit. Keep in mind that this is just a general recommendation, shorter riders will want to use even shorter handlebars.
Conclusion: Mountain Bike vs. Gravel Bike
While there isn’t a simple answer that will work for everyone, I still feel that a mountain bike is the better all-around choice. Even using just a few of the recommendations to overcome it’s limitations for gravel rides is more than enough to make it the better choice in my opinion.
Of course, if you expect to never need to tackle singletrack then a mountain bike may very well be overkill. However, you best know your intentions and the area around so I’ll leave the final call up to you!
- What’s the difference between a mountain bike and hybrid bike? The primary differences between a hybrid and mountain bike are that a hybrid bike has a more lightweight and aerodynamic frame, thinner smooth tires, use rim instead of disc brakes, and generally do not have suspension. For these reasons, hybrid bikes are better suited to the road, gravel, or dirt paths than rugged off-roading. For more information, click here to take a look at the full article that I wrote on this topic.
- How do I fit a bike in my car, truck, van, or SUV? Regardless of whether you drive a car, truck, van, or SUV – there’s always a way to make your bike fit in your vehicle. If it doesn’t fit in the trunk area, try removing the front wheel, lowering the bike saddle, laying down the vehicle’s back row seats, or removing pedals until it fits. For more information, click here to take a look at the full article that I wrote on this topic.
- Why do my wrists hurt from biking? Most wrist pain in mountain biking is a result of bad posture or poor bike setup. Focus on keeping your wrists in a neutral position, shifting your weight off your hands and onto your pedals, and avoid gripping the handles too tightly. Double-check that the bike is properly set up for you. For more information, click here to take a look at the full article that I wrote on this topic.