What Is A Gravel Bike?

Curious about the hype surrounding gravel bikes?

Pondering how they carve out their niche amidst road and mountain biking brethren?

Gear up, as we pull back the curtain on the world of gravel bikes…

Combining the best of both road and mountain biking, a gravel bike is a versatile two-wheeled companion designed to conquer a variety of terrains.

In this concise guide, you’ll find an answer to the question, “What is a gravel bike?” and unlock a whole new realm of cycling possibilities.

What Is A Gravel Bike And What Is It Used For?

A gravel bike is a versatile bicycle designed to tackle diverse terrains such as gravel paths, dirt trails, and even paved roads.

With a cursory glance, it resembles a road bike, but a closer look gives away its off-road pedigree and potential.

Among the features that define a gravel bike are its robust frame, wider tires for improved traction, and a more relaxed geometry for stability and comfort over long rides.

Disc brakes provide reliable stopping power and allow ample clearance for mud and debris.

Gravel bikes are used for adventurous off-road exploration, endurance rides, and bike-packing.

A gravel bike is a great option for riders seeking just one bike to devour the miles.

These bikes are nothing if not versatile.

Gravel bikes are adventure bikes, touring bikes, and racing bikes.

A number of pro cyclists have taken up gravel racing after road racing in recent years, partly because of their relaxed atmosphere and greater level of personal freedom.

Video: A Gravel Meditation: Scenes From Forgotten Roads

Parts Of A Gravel Bike

Frame

Gravel bikes are made of steel, titanium, aluminum, and carbon.

Steel is a popular material because it’s naturally strong yet compliant and comfortable.

It’s an especially good choice for bike-packing.

Titanium achieves the same with less weight and no rusting.

Advanced manufacturing methods like hydro-forming help to produce sleeker, more comfortable aluminum bikes.

Often, aluminum bikes have a steel or carbon fork to reduce vibration and improve ride quality.

Carbon frames are lightweight, stiff, and yet comfortable.

They’re ideal for long rides and races.

Wheels

Gravel bikes typically have wheels with either 700c or 650b diameters.

In sizes familiar to mountain bike riders, these are 29″ and 27.5″ respectively.

Which of these wheel sizes is best?

The thing about the smaller wheel is that it can take bigger tires, which can make its total diameter equal to the larger 700c wheel.

Larger, fatter tires are usually more comfortable to ride on, so why wouldn’t you always pick the smaller wheel?

Answer: because the 700c wheel is the quicker, smoother option if you’re riding a lot on asphalt or moderately smooth or compacted trails.

You’d go for a gravel bike with 700c wheels if you intended riding on the road a fair bit or any surface that wasn’t overly bumpy or grimy.

The 650b wheels with fatter, thicker tires will slow you down on such surfaces owing to their greater rolling resistance.

A 700c wheel is better if you only ride one bike and want maximum versatility for on-road and off-road riding.

It’ll still accept a wide tire by most standards.

On rougher surfaces, there will be a crossover point where the smaller 650b wheel with fatter tires becomes faster than the 700c.

Smaller wheels make bicycle steering more responsive, so 650b wheels work well for technical off road terrain.

All else being equal, smaller wheels are also stronger because their spoke lengths are shorter.

This might be something you’d factor in if you intended carrying a lot of gear on a bike-packing trip.

Video: Should You Go 650b?

Gravel Bike Tyres

As with all bikes, the types and sizes of gravel bike tyres you choose will depend to an extent on your wheels, as above, and the clearance for tires that your bike allows.

One of the catalysts for gravel popularity over recent years is disc brakes.

Bikes with rim brakes automatically limit the width of tire you can fit on a bike.

The clearance for wide or large tires offered by a bike also depends on the room around its seat stays, chain stays, the fork, and the fork crown (the apex of the fork).

In very rare cases, a 650b wheel takes gravel bike tires up to 2.5″ wide, which is firmly in MTB territory.

A 700c gravel wheel accepts tires up to 50mm wide, frame clearance allowing.

Choosing Tires For Gravel Bikes

The above details are all very well, but what should you look for in a gravel tire?

A thinner tire with a slick or semi-slick tread will roll faster on asphalt or smooth trails than a wider tire with a knobby tread.

That’s because rolling resistance is lower.

The thinner tire will also typically be inflated to a higher pressure.

As far as comfort goes, wider tires are more comfortable as long as you exploit the leeway they offer in riding lower pressures.

If you pump a wide tire up to its max, it’s not necessarily any more comfortable than a thinner tire, as the casing tension is greater.

Read more: How to choose the right bike tire pressure

In summary, pick a wide, knobby tire if you intend riding a lot on rough, loose terrain, or a slick, narrower one if you’ll ride quite a lot on asphalt, fire roads or other compact surfaces.

Versatile Gears

Gravel bikes have one or two chainrings at the front (1x or 2x drivetrain) and a gravel-specific cassette at the rear.

The gearing of gravel bikes lies somewhere between that of mountain bikes and road bikes.

You’ll have some reasonably “quick” high gears on a gravel bike for descents or riding swiftly on smooth surfaces.

You’ll also have super-low gears to help you traverse rougher terrain.

Big, wide gravel bike wheels are inherently harder to push than smaller wheels, so you need lower gears to counteract that, too.

The lowest gear ratio on a gravel bicycle will often be below 1:1 (e.g., 0.83:1), meaning the rear wheel makes more than one revolution per pedal stroke.

Gravel Disc Brakes

Unless you’re looking at an exotic machine like the English Cycles “Bowei’s gravel bike“, every gravel bike you look at will have disc brakes.

An old cyclocross bike or a mountain bike may have cantilever rim brakes.

Disc brakes do not limit tire width, hence their proliferation on gravel bikes.

Rim brakes typically limit tire width to 28mm or thereabouts.

Disc brakes come in two forms: mechanical and hydraulic.

Just like rim brakes, mechanical disc brakes use a steel cable inside a housing.

Hydraulic disc brakes are considered superior, though both types offer more braking power than rim brakes.

Gravel Bike Geometry

The main preoccupation in gravel bike geometry is stability.

The idea is to make off-road gravel riding reliable and easy to handle, where the bike is not easily knocked off course.

What is a gravel bike in terms of its geometry?

Long Wheelbase

One of the defining features of gravel bike geometry is a long wheelbase.

A long wheelbase makes the bike stable, and this is a valuable attribute on a gravel bike, as it makes the handling more predictable and controllable over a variety of surfaces.

Wheelbase is defined by other elements of bike geometry, like the chainstay length, head tube angle, and fork rake.

Long Chainstays

Most gravel bikes have long chainstays.

As mentioned above, this increases the wheelbase length, but long chainstays also provide more clearance for wide tires.

Chainstays become wider the further they travel from the bottom bracket, and length differences of only 15-30mm greatly affect the tire widths a bike can accommodate.

Short Top Tube

Gravel bikes tend to have a slightly shorter effective top tube length than other bikes with drop bars, though this varies a little.

The shorter top tube places the rider in a more upright, less stretched out position than other drop handlebar bikes.

This creates more comfort but also enables a central position over the bike, which aids control over rougher terrain.

Slack Head Tube Angle

Often combined with a tall head tube, the slack head tube angle of a gravel bike increases the wheelbase length.

It also increases a measurement known as “trail”.

Learn more about trail here: What is trail in bike geometry?

Trail is the distance between the contact point of the wheel and the projected axis of the steerer tube.

The longer this measurement is, the calmer and more stable steering is.

The fork rake or fork offset in a gravel bike, or any bike, also affects trail.

Fork offset describes how far the front axle is in front of the steerer tube axis.

More fork rake = less trail and more responsive steering.

You might guess that a gravel bike has very little fork rake to further increase its stability.

In fact, it’s often comparatively high to avoid excessively sluggish handling.

Fork rake is higher in gravel bikes than it is in comparable bikes with livelier steering (e.g., road bikes).

The tall head tube of a gravel bike promotes a more upright posture in the rider.

Bottom Bracket Drop

Bottom bracket drop measures the vertical distance between the center of the bottom bracket and the center of the front and rear wheel axles.

Unlike bottom bracket height, it is unaffected by wheel or tire size.

More bottom bracket drop or less bottom bracket height are generally good for bike stability, as the center of mass is lowered.

Arguments against this such as the increased likelihood of pedal strikes are less pertinent to gravel bikes than mountain bikes.

Gravel Bikes Compared To Other Bike Types

Gravel bikes have only really been “a thing” for about a decade or so.

How do they compare to more established machines?

Gravel Bike Vs Road Bike

A gravel bike is undoubtedly more versatile than a road bike, being eminently rideable on asphalt as well as off-road, depending a bit on its wheels and tires.

It has a more relaxed geometry that places emphasis on stability and handling over varied surfaces.

The main benefit of a road bike over a gravel bike is that it’s quicker over flat surfaces owing to lower rolling resistance, better aerodynamics, and highly efficient power transfer.

You’re likely to be 1 or 2 mph faster riding a road bike on the road vs a gravel bicycle.

Gravel bikes tend to be a bit heavier than road bikes because of their chunkier build.

They need to be stronger for their off-road remit.

Steering is more agile and responsive on a road bike owing to a steeper head tube angle and shorter wheelbase.

A gravel bike is likely to be more comfortable to ride than a road bike owing to its wide tires and more upright riding position.

However, there are many variables in bike comfort.

Gravel Bike Vs Cyclocross Bike

Cyclocross bikes are more specialized, niche machines that don’t have the broad market appeal of gravel bikes.

They’re often designed for racing around technical off-road courses, and as such they have more responsive steering than gravel bikes do.

The geometry of a gravel bike is more relaxed than that of a typical cyclocross bike (or road bike), not least because gravel routes and rides tend to be longer.

CX bikes promote a more stretched out aerodynamic riding position.

Tire clearance on a cyclocross bike is less than that of a gravel bike.

CX tires typically go up to about 35mm, so they’re a bit narrower on average than gravel tires.

A CX bike usually has a narrower gear range than a gravel bike but wider than a typical road bike.

Gravel bikes are normally better equipped for adding extras such as panniers, fenders, and multiple water bottles.

You won’t find the same in most CX bikes.

Gravel Bike Vs Mountain Bike

Mountain bikes are better than gravel bikes over the roughest, rockiest, most gnarly terrain.

Aside from old-school 1990s MTBs, they always have suspension, whether it’s the front suspension of a hardtail or front and rear shocks of a full-suspension MTB.

Gravel bikes rarely have suspension.

The tires aren’t as wide, either. MTBs can have 5″ wide tires in their “fat bike” category, but even a regular model has wider tires on average than a gravel bike, with a smidgeon of overlap.

On the road, a gravel bike is faster than an MTB, even if it’s a hardtail with suspension lockout and slick tires.

The more aerodynamic riding position and lower rolling resistance you’d experience on a gravel bike would cover distance quicker.

To help them cope with technical trails, MTBs have an even more relaxed geometry than gravel bikes.

The head tube angle is slacker and the wheelbase is longer.

MTB riders have a more upright riding position, and of course the handlebars are flat.

Gravel bikes always have drop bars, hence their cursory resemblance to road bikes.

Gearing on mountain bikes tends to be more biased towards the easy end with some very low gears for climbing.

The lowest gears on gravel bikes are often not quite as low, but this reflects their different function.

A gravel bike is a do-it-all bicycle that dabbles successfully in paved and off-road riding.

It’s not intended for technical terrain full of roots and rocks, nor will it beat a dedicated roadster on asphalt.

But it gives you choices.

Video: Gravel Bike Vs Hardtail MTB

Advantages Of Gravel Bikes

Gravel bikes, also known as adventure bikes, have gained tremendous popularity in recent years.

They offer a range of advantages.

Versatility

Gravel bikes excel in their ability to tackle various terrains.

Whether it’s smooth pavement, gravel roads, dirt paths, or even light trails, these bikes are designed to handle it all.

The wide tires, typically ranging from 32 to 45mm, provide stability and grip on uneven surfaces, while the relaxed geometry and disc brakes enhance control and boost confidence.

Ride Comfort

Gravel bikes feature a more relaxed and upright riding position compared to traditional road bikes.

This upright position reduces strain on the neck, shoulders, and lower back, making long rides more comfortable.

Additionally, the wider tires and frame design help absorb vibrations and bumps, further enhancing comfort on rougher surfaces.

Off-Road Capability

Gravel bikes are equipped with features that make them capable off-road performers.

They have a sturdy frame construction, wider tire clearance, and robust components that can handle rougher terrains.

Gravel bike attributes open up a whole new world of exploration, allowing riders to venture off the beaten path and discover new routes and landscapes.

Increased Stability

The combination of wider tires, a long wheelbase and relaxed geometry provides increased stability, especially at higher speeds and on loose surfaces.

This stability inspires confidence and allows riders to maintain control and balance under challenging conditions.

Commuting and Touring

Gravel bikes are excellent choices for commuting and touring purposes thanks to their ability to handle a variety of surfaces.

They offer much of the speed and efficiency of a road bike on paved roads while allowing the freedom to improvise.

You can take a gravel bike off road for unscheduled shortcuts.

With the addition of racks and panniers, they can haul luggage and gear for longer trips.

Adventure and Exploration

Gravel bikes encourage a sense of adventure and exploration.

They enable riders to go beyond traditional road routes and discover hidden gems in nature.

Whether it’s exploring remote countryside roads or embarking on multi-day bike-packing trips, gravel bikes offer the freedom to push boundaries and seek new experiences.

Disadvantages Of Gravel Bikes

While gravel bikes offer many advantages, it’s important to consider their potential disadvantages as well.

Limited Speed on Smooth Surfaces

While gravel bikes are designed to handle different terrains, their wider tires and more relaxed geometry can lead to reduced speed on smooth, paved roads compared to road bikes.

This is because of increased rolling resistance in the tires and an aerodynamic disadvantage in the more upright riding position.

Limited Off-Road Capability

While gravel bikes are versatile, they have their limits when it comes to extremely challenging off-road conditions.

They may not perform as well as mountain bikes on technical singletrack trails or extremely rocky terrain.

The geometry and suspension of MTBs provide better control and handling in more demanding environments.

If your primary focus is off-road riding on highly technical trails, a dedicated mountain bike would be a better choice.

Video: Can You Ride A Gravel Bike On An MTB Red Trail?

Additional Weight

Gravel bikes often feature robust frames, wider tires, and sometimes even added accessories like racks and fenders.

While these elements contribute to their versatility and durability, they also add weight to the bike.

The extra weight may be noticeable when accelerating, climbing steep hills, or through the accumulated fatigue of extended rides.

Riders who prioritize lightweight performance may find dedicated road bikes more appealing.

Read more: What is the average weight of a bike?

Price Of Entry

Gravel bikes aren’t hugely different in price to road bikes unless you’re on a tight budget.

You can’t buy a gravel bike for below 500 dollars or euros, for instance, whereas you can pick up a rideable road bike for that kind of cash.

You need 700 or 800 dollars for an entry-level gravel bike.

Beginner’s hybrid bikes and road bikes cost 30-40% less.

Whatever the cause, (possibly the cost of componentry) it’d be nice to see a gravel bike that didn’t put quite such a dent into a modest wage.

Frequently Asked Questions About Gravel Bikes

What Types Of Terrain Are Gravel Bikes Best Suited For?

Gravel bikes are suitable for paved roads, dirt roads, fire roads, gravel paths, and smooth single-track trails.

Can I Use A Gravel Bike For Long-Distance Touring?

Yes, you can use a gravel bike for long-distance touring, especially if some of it is off-road.

Not for nothing are gravel bikes known as adventure bikes.

What Should I Look For When Buying A Gravel Bike?

Look for ample tire clearance in the frame and fork, aim for a wide gear range, and consider wheel sizes and the type of terrain you’ll ride on.

The widest tires fit onto 650b wheels and are best suited to off-road riding, whereas 700c wheels are good all-rounders for roads and gravel.

Are Gravel Bikes As Fast As Road Bikes?

They’re faster off-road, where a road bike will often struggle to go, but not as fast as a road bike on smooth paved surfaces.

Can I Use A Gravel Bike For Commuting To Work?

Yes, a gravel bike is ideal for commutes to work, especially if you have the opportunity to take some off-road shortcuts and avoid heavy traffic.

Conclusion On Gravel Bikes: Unpaved Roads With Unmatched Fun?

Are you bored of always riding the same routes on pavement?

Gravel bikes offer the ability to explore a variety of terrains, making rides more exciting and enjoyable.

Gravel bikes are adventure bikes.

They let you improvise and get off the beaten track, away from trucks and cars.

Yes, they’re fun.

We hope you enjoyed this article.

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