Do you need a gravel bike to ride gravel roads? Of course not. One of the most appealing things about gravel riding is the lack of hard-and-fast rules. Your endurance road bike or cyclocross bike can easily be transformed into a gravel-capable machine with nothing more than good tires and a sense of adventure.
Gravel bikes have become popular because, compared to road bikes and cyclocross bikes, gravel bikes offer better comfort and stability. They have more relaxed geometry and much more tire clearance. These features enhance the experience of riding dirt, trails, gravel, logging roads, and everything in between.
But what about the original off-road machine? Long before the gravel trend, people were already riding mountain bikes on dirt and gravel roads. And though gravel bikes look a lot like road bikes, most of the technology — such as tubeless tires, disc brakes, and clutch derailleurs — was adapted from mountain bikes.
When looking for a new bike, some riders may find themselves torn between choosing a gravel bike and a fast XC mountain bike like a 29er hardtail. Both are good options for exploring mixed terrain from gravel roads to light singletrack trails. But what are the advantages and disadvantages of each. Which is better for you?
Drop vs. flat handlebars
If you needed to pick one physical trait to separate gravel bikes from mountain bikes, the handlebars are most obvious. Gravel bikes use drop handlebars while mountain bikes use flat handlebars.
Though it is possible to quibble with this distinction — flat bar gravel bikes and drop-bar mountain bikes are rare but they do exist — it serves as a very reliable indicator of a bike’s intentions.
Gravel bikes use drop handlebars because they are normally ridden at higher speeds on smoother roads and over longer distances. Drop handlebars are standard equipment on road and cyclocross bikes because they provide more hand positions. The ability to adjust your hands improves comfort and reduces fatigue on long days in the saddle. The drops also provide a lower, more aerodynamic position and leverage for sprinting. Drop bars give gravel bikes versatility for riding at high speeds, as they are meant to transition easily between paved and gravel roads. These bars are also usually narrower, making them better for riding shoulder-to-shoulder with other riders during group rides and races.
Mountain bikes use flat handlebars because they provide more control in off-road terrain. Flat bars are wider than drop bars and provide stability and leverage. On rough and technical singletrack trails, they make it easier for riders to maneuver and hang on to their bikes. Flat handlebars often position the rider more upright with their hands further apart. This can be more comfortable, but it makes you less aerodynamic when riding at higher speeds on smooth, open roads. Flat bars are best for the slower speeds encountered on singletrack trails.
Gravel bikes can fit wider tires than road and cyclocross bikes, generally in the 38-45mm range. A few models are now capable of fitting up to 50mm tires. Wide tires are good for gravel riding because the increased tire volume improves comfort and traction.
The largest gravel tires are still narrower than most mountain bike tires. The majority of XC mountain bikes are designed to fit tires in the range of 2.1-2.4” wide (50mm gravel tires measure about 1.97”). Mountain bike tires will have more weight and rolling resistance but offer the most comfort and traction.
Like the handlebar comparison, gravel bike tires have an advantage on faster, smoother terrain, while mountain bike tires can handle rougher roads and trails.
Suspension takes the edge off of the bumps and increases comfort and control. Most mountain bikes have at least a suspension fork, but the majority of gravel bikes are "rigid" to save weight and maximize pedaling efficiency.
There are a few gravel bike models that utilize suspension, but they are rare. Many riders who desire suspension for their gravel bike will need to purchase aftermarket suspension forks.
Notable examples of gravel-specific suspension forks are the Lauf Grit fork, RockShox Rudy, FOX AX fork, and MRP Baxter fork. These forks provide significantly less travel than mountain bike forks — 30-40mm.
The Lauf Grit SL gravel suspension fork.
This small amount of travel can smooth out bumps and chatter on rough gravel roads while remaining efficient enough for smooth gravel and paved roads. But if you're used to the plush comfort of a mountain bike fork, you will find them to be pretty firm.
Read more: Do gravel bikes need suspension forks?
As a broad generalization, gravel bikes will have “harder” gearing which will allow riders to continue pedaling when riding at higher speeds. Mountain bikes will have relatively “easier” gearing that suits steep and technical off-road climbs. Both gravel and mountain bikes have limitations when it comes to gearing.
Take, for example, a gravel bike and a mountain bike each equipped with the latest SRAM 1x drivetrain. Gravel bikes with a XPLR eTap AXS gravel drivetrain might use a 42t chainring and a 10-44t cassette. Mountain bikes with an Eagle drivetrain might use a 32t chainring and a 10-50t cassette.
Both have pretty wide gear ranges. However, the hardest gear combinations provided by the drivetrains are very different: 42t-10t and 32t-10t, respectively. Because the gravel bike is able to fit a much larger (42t) chainring, you are less likely to “spin out” or run out of gears when pedaling at high speeds (above 20-30mph).
The easiest gear combinations are 42t-44t and 32t-50t. Because the mountain bike provides a substantially lower gear, it will be much easier to pedal up difficult climbs.
Of course you can customize your drivetrain to suit your needs, but most stock gravel bikes come geared for faster riding. They will generally have a larger 1x chainring or a 2x set-up.
Read more: 1x vs. 2x gravel drivetrains
Mountain bike gearing might be more desirable for gravel riders who need an easier gear for hard climbing, riding while loaded with heavy bike-packing gear, or riders riding slow, technical gravel and singletrack trails.
Gravel bikes can be converted to use a mountain bike drivetrain (e.g., SRAM AXS allows for a “mullet” set-up using the 10-50t mountain cassette). But most mountain bikes don’t have enough clearance to fit the larger chainrings of gravel bike drivetrains and top-end speed will always be limited compared to gravel bikes.
Read More: Do you need an electronic shifting?
Compared to road or cyclocross bikes, gravel bikes place riders in a more upright, endurance-oriented position for stability, control, and comfort when riding off-road. Gravel bikes can be considered a middle ground between road bikes and mountain bikes. Mountain bike geometry is even more upright and won’t feel as quick-handling on pavement or smooth gravel, but it feel more stable and confidence-inspiring on extremely rough gravel and singletrack trails.
Comfort and fit
On gravel, the majority of riding comfort will come from the tires. Larger tires have more air volume, and can be run at lower pressure to absorb bumps and vibrations. Gravel tires in the 38-45mm range will be fine for typical gravel roads. If you’re riding a lot of extremely rough terrain (e.g., gravel with loose-golf-ball- to baseball-sized stones, deep ruts, roots, and large embedded rocks) or trails, you may benefit from the larger tires and additional suspension offered by mountain bikes.
Most gravel bikes are already designed to provide a fairly comfortable riding position, but if you have severe flexibility limitations or other comfort issues that a gravel bike can’t accommodate, a mountain bike that provides a more upright position is a good option.
Confidence and capability
If you’re not comfortable riding on dirt and gravel or you're regularly riding singletrack trails, mountain bikes are the better option. The combination of flat handlebars, suspension, wider tires, and mountain bike geometry gives riders maximum stability, traction, and control. That's great for pushing the limit or getting comfortable venturing away from the pavement.
But unless you start venturing into tougher mountain bike trails, you might begin to desire more speed and efficiency. Plus, riding gravel bikes on singletrack can still be extremely fun and rewarding. You may be surprised by how much rough and technical terrain you can successfully ride.
Even if you aren’t riding difficult terrain, a mountain bike could help you ride faster if you struggle with confidence when cornering, braking, or descending on gravel roads. (If you’d like tips specifically about how to corner, brake, and descend on gravel, read our Guide to Riding Gravel.)
Speed and efficiency
On smoother surfaces, whether paved or gravel, a gravel bike will be much faster and more efficient (it'll require less energy to pedal) than a mountain bike. Drop bars offer a more aerodynamic profile. Narrower tires have less rolling resistance. And the harder gearing is better for high speeds.
Fitness is a big factor, but it will always be much easier to keep up with a fast gravel group ride while on a gravel bike. If the terrain is smoother and flat, rolling, or downhill, a gravel bike will get up to speed and maintain speed more easily.
Mountain bikes will, of course, be faster than gravel bikes on true mountain bike terrain like technical singletrack trails.
Weight is also a consideration. Gravel bikes often weigh less than comparable mountain bikes.
What is your local terrain like? What type of roads or trails do you ride regularly? Let’s say you mostly ride from your house to explore dirt and gravel roads. You might have to ride several miles of paved roads through town before you get out to the good stuff. In this case, a gravel bike that balances efficiency on the pavement with fun on the gravel would be ideal.
If you dream about wandering onto poorly maintained Jeep roads or rocky and rooty singletrack, then a cross-country mountain bike might be better. It will allow you to explore the worst terrain you will encounter.
Beyond your terrain, goals might influence your decision. Is your dream to finish the Unbound 200 gravel race or something similar? If you want to ride hard in a group of riders, race competitively, or just go fast and set new personal bests, then a more efficient race-focused gravel bike will be more desirable. On the other hand, if your friends might talk you into off-road races like the Epic Rides series or Leadville Trail 100, a mountain bike is the more versatile setup.
Who has the better bike in this situation?
Choosing the right bike can be agonizing. I’ve made those tough decisions over the past few years. I’ve been on plenty of rides where both gravel bikes and mountain bikes were present, and I've experimented with different gravel bikes and even a hardtail 29er mountain bike.
I successfully race a gravel bike for several years, then in late 2018, I began fantasizing about doing rides that would explore more rugged trails and have one bike that could do everything. I switched to a hardtail 29er with a rigid carbon fork. The fork reduced weight and improved pedaling efficiency. The flat bars and large 2.35” tires made it confidence-inspiring on singletrack trails.
This bike allowed me to continue participating in gravel group rides. Whenever we dropped into a section of singletrack or encountered sand or snow, I would leave most gravel bikes behind. This bike was fun, capable, and versatile.
Over time, my goals shifted toward competition, and the 29er hardtail simply couldn’t keep up. Top speed was limited by aerodynamics and gearing. I found myself regularly spun out and getting dropped when speeds started entering the mid-20s.
I've returned to a faster and more efficient gravel bike because I want every advantage possible. Gravel riding is still evolving. And I'm always evolving as a rider. Whatever bike you're on, the most important thing is that it can put a smile on your face. The only gravel "rule" you should worry about is having fun.
Have you used a mountain bike for gravel riding or a gravel bike on mountain bike trails? What bike do you choose and why? Let us know in the comments!