What Is a Gravel Bike and Do You Need One?

Published on 05/13/2023 · 9 min readCycling Expert Jared Fontaine details what a gravel bike is, the different types of gravel bikes, and what each type is best suited for!
Jared Fontaine, Cycling Expert
By Cycling Expert Jared Fontaine

187-mile-long gravel trail from DC to Cumberland MD. Photo by Jared Fontaine

As the population increased in Boulder, Colorado, in the 2010s, roadies found that the number of crazy, impatient drivers blowing car exhaust in their faces also increased. So, they thought, wouldn't it be nice to take our road bikes on less busy gravel roads? Their calls were answered with the invention of the gravel bike.

What Is a Gravel Bike?

A gravel bike is a drop bar bike with wider tires—around double the size of a road tire—to ride on gravel and pavement. It is faster than a mountain bike and can be ridden in mixed terrain. Most gravel bikes can fit 40mm-wide knobby tires that can grip loose terrain, which is around twice the size of a slick road tire.

Gravel bikes generally have more stable handling characteristics due to a longer wheelbase and more relaxed frame geometry. They are also a little bit more durable and robust to crashes than a road bike. Currently, many gravel and road bikes are blending together to serve as a do-it-all bike.

Do You Need a Gravel Bike?

If you’re like me, and you believe in the “N + 1” principle—where “N” is the number of bikes you currently own, and “1” being that you will always want a new bike—then yes, you will need a gravel bike. However, an all-road gravel can also end N + 1 cycle, because gravel bikes allow riders to cycle over multiple terrains while still feeling snappy.

With an allroad gravel bike, you get the versatility of mixed terrain riding with the speed and lightweight of a road bike. So, unless you require the lightest, fastest road bike, there are very few reasons to use a regular one. However, endurance road bikes are squeezing into the gravel bike terrain, as many endurance road bikes—like the Cannondale Synapse—can fit 35mm tires.

Gravel Bike or Endurance Road Bike?

If the majority of your riding will be on gravel (around 70% gravel, 30% pavement), then I would go with a gravel bike—as you will probably be venturing deeper into the woods and are more likely to use the extra grip on gnarly rock.

However, if you are like me and ride 90% road and 10% gravel as a shortcut, then an endurance road bike with 32mm tires will be a better option. Experienced, hard-nosed roadies use 25mm, slick tires on shortcut gravel roads when they are only traveling a few miles and can bear the discomfort.

But keep in mind, when I rode my endurance road bike on a trail like the C&O Canal between D.C and Maryland, I found that I really needed a larger, knobby tire—as the trail has lots of roots and mud pits that were not fun to hit riding at 20 mph. The ride was uncomfortable, and the roots would often launch the bike into the air. Even for a 10-mile shortcut, it was too much.

Gravel short cut to work. Photo by Jared Fontaine

So, if you want to attempt a trail like this, I suggest you ride a tire with knobs and at least a 35mm tire or higher. A broader tire—especially a tubeless tire—can be filled with less air pressure to give you more suspension and absorb bumps and roots.

Gravel Bike Tires

Now that tubeless tires are widespread in both the road and gravel cycling scene, gravel riders have the same advantages that mountain bikers have had for years: lower tire pressure without pinch flats and flat prevention. Before tubeless tires, most gravel riders would use clincher tires with a tube inside. If a thorn were to puncture the tubeless, the tire would go flat. But since tubeless tires have a sealant that fills most punctures, gravel riders can be nearly flat-free.

A pinch flat happens when the tire pressure is so low that the rim pinches the inside tube, or when a rider hits a big enough object to pinch the tube. Without a tube, it is impossible to get a pinch flat. You can run lower tire pressure, giving gravel riders more grip on loose terrains like mud or snow. So, when purchasing a gravel bike, I highly suggest the bike should be set up tubeless. It decreases the chances for punctures over the rough terrain of thorns, sticks, and rocks on gravel roads.

Gravel bike tires also have different levels of tread for different surfaces. If you live in sandy, desert terrain, then I suggest a tire like the Vittoria Terreno DRY G2.0 Tire, which has fine tread for grip. If the terrain you ride is normally super wet with lots of mud, you will need a tire with a more aggressive, knobby tread, like the Maxxis Rambler 700c.

When I owned a cyclocross bike—which is similar to a gravel bike, in that it is an offroad drop bar bike, but has features like a higher bottom bracket and a shorter wheelbase—I owned two wheelsets. One for commuting, and the other for cyclocross races and snow riding. One set had slick 28mm tires for riding on pavement, and the other set had 33mm knobby tires for gravel riding.

Commuting

Gravel bikes are great "B bikes" or commuter bikes. Riders can save their expensive summer road bike from the poor conditions and ride a lower-cost gravel bike in the winter.

In the winter, grit and dirt can destroy your components. The benefit of most gravel bikes is that they have a 1x drivetrain—or one chainring in the front with a wide-ranging cassette in the back—which means one less derailleur to adjust. Also, most gravel bikes are equipped with gravel-specific groupsets like Shimano's GRX groupsets. These are designed to be ridden in the mud and dirt, and are perfect for the grind of the commuter longing for low-maintenance components.

Gravel short cut to work. Photo by Jared Fontaine

Since gravel bikes are designed to take a beating and, on average, have a more stable, upright riding position, they are an excellent option for commuters looking for a fast, fun ride to work. I used a cyclocross bike for a 26-mile commute to work in West Virginia; I loved that I could fit 28mm Continental Four Season Tires to get plenty of grip on most surfaces. And now that the industry has moved to wider tires, you can use 32mm tires for extra comfort and grip.

Commuting in the winter. Photo by Jared Fontaine

Some gravel bikes also have eyelets for fenders and racks and a more extended wheelbase than a traditional road bike—making the bike feel more stable at slow speeds. Also, they feature a more upright position for sightseeing in slow traffic.

Subgroups of Gravel Bikes

Gravel is basically the wild west of bikes nowadays, as new innovation is constantly being included with each new year’s model. This includes full-suspension gravel bikes with front and rear suspension that can race road bikes. Next, we will dive into a few more of the unique offerings of gravel bikes.

Full Suspension

The Gravel NINER - 21 MCR 9 RDO 

Since the UCI World Tour does not regulate most mountain bikes as they do road bikes, mountain-bike-specific companies generally experiment with very different types of technologies and components. For example, Niner’s full-suspension gravel NINER - 21 MCR 9 RDO is a mountain bike with drop bars. So, you can ride this bike on most single tracks; however, it is heavier and not meant for road riding.

Short Travel Suspension

Traditional road-bike brands offer full suspension gravel bikes with 20–30mm of suspension travel (the distance the suspension on a bike can move) to absorb bumps in the road; and you can lock out the travel for faster riding. Also, these bikes are not as heavy as complete-suspension gravel bikes. For example, Cannondale makes the Topstone Lefty gravel with 30–50mm of travel front and rear for more comfort.

Touring Gravel Bikes or Adventure Bikes

Some companies are leaning into bikepacking by offering bikes with a longer wheelbase for stability when carrying up to 100lbs of camping gear and other luggage, a more upright position for long days in the saddle, and sightseeing. These frames are generally made from steel, as it is easier to repair on a round-the-world trip. Steel also offers legendary compliance and comfort.

Moreover, these frames have eyelets on the forks, downtube, top tube, and rear to allow for carrying heavy camping gear, extra water bottles, and a top tube bag to hold snacks and mudguards. Bikes like the Marin Four Corners fit into this type of gravel bike.

Flat Bar Gravel Bikes

Some riders want a gravel bike but don't like the drop handlebar. Older riders wish to have a flat handlebar like a mountain bike but desire the speed of a gravel bike. Marin has the DSX, a high-end Shimano GRX groupset with a flat handlebar and 700 c wheels. Some models have a front suspension fork to take the edge off the gravel.

Which Should I Consider?

In order to answer that question, we have to review three things: experience cycling, goals, and terrain.

Experience

If this is your first bike since you were a kid, I’d check out an all-arounder bike like the Cannondale Topstone 1—which has mounts, light bikepacking, stable handling, and a reasonable price range. If you are a more experienced road cyclist, then a full-carbon Cervelo Aspero or Pinarello Grevil is a better pick for lightness and speed. On the other hand, if you are coming from the mountain-biking scene, a bike with a slacker headtube with more suspension travel and a dropper post would be a better option.

Goals

If you are looking to commute or bikepack across the country, then the DSX or the Four Corners are better choices than something like a Marin Headlands, which features a carbon frame meant for racing.

Terrain

If you use your bicycle more for road cycling, then an all-road gravel bike would be a better choice than a traditional gravel bike. On the other hand, if you are looking for more of a mountain bike, a slacker headtube, like the BMC URS AL ONE would be better.

Final Thoughts

Gravel short cut to work. Photo by Jared Fontaine

If you’re still debating on whether or not a gravel bike is appropriate for your needs, or if it’s simpy time for a bike upgrade, there’s a place you can go. To explore more Cycling articles as you pursue your journey in the sport, check out the Expert Journal here on Curated.

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