Head to Head: Road vs Gravel Bikes

Frame geometry

The most noticeable difference between a road and a gravel bike is the frame geometry.

Road bike geometry is lower and more aggressive

Road bikes have a longer top tube, shorter head tube, lower stack height, and steeper head and seat tube angles. The steeper head angle and shorter wheelbase also contribute to agile handling, ideal for navigating sharp turns and cornering at high speeds. 

This design places the rider in a more aerodynamic position, with more weight over the front wheel for improved handling at high speeds.

Gravel bike geometry is more relaxed

Gravel bikes have a higher stack height, a shorter top tube, a taller head tube, and slacker head and seat tube angles. The lower bottom bracket, slacker head angle, and longer wheelbase are all intended to make the bike more stable on rough terrain, which can be unpredictable and require quick and sudden changes in direction.

This design places the rider in a more upright position, which is more comfortable for long rides and allows for better visibility on rough terrain. Gravel bikes also have wider tires and a higher stack height, contributing to a more stable and comfortable ride on unpaved roads.

Some gravel race bikes, such as the Cervelo Aspero 5, have more aggressive geometry similar to road bikes, with a more aerodynamic riding position and greater emphasis on speed and agility. These gravel bikes are for competitive gravel racing, where speed and efficiency are paramount, and riders must navigate quickly and confidently through various terrain.

Drivetrain setup

If you primarily ride on smooth roads and want to maximize speed and efficiency, a 2x road drivetrain may be the better choice. However, if you plan to ride on rough terrain and need more low-end gearing for climbing a 1x or 2x gravel drivetrain may be a better option.

2x drivetrain

Road bike gearing setup is typically a 2x drivetrain with two chainrings. The larger outer chainring is for achieving high top speeds on flat terrain, while the smaller inner chainring is for climbing steep hills. 

Because road riding is typically faster, road bike cassettes have a tighter gear range with more 1-tooth steps between gears. This allows for a smoother transition between gears, making it easier for riders to maintain a comfortable pedaling cadence at speed.

1x drivetrain

Gravel bikes, on the other hand, commonly use a 1x drivetrain. Single-chainring (1x) drivetrain technology originated in mountain biking and has become increasingly popular among gravel riders. 

Many riders prefer 1x because it simplifies shifting by eliminating the front derailleur. Additionally, the narrow-wide chainring design provides better chain retention on rough roads.

Gravel bike gearing places a greater emphasis on easy gears, or granny gears, which are better for climbing steep hills and riding on loose surfaces. Most gravel riding is at lower speeds, so it’s important to have a wide gear range that can handle a variety of terrain. 

• 1x drivetrains have wide-range cassettes with a low gear ratio, such as SRAM’s 10-42T or 10-52T, which provides plenty of low-end gearing for climbing. 
• 2x drivetrains use smaller chainrings than standard road drivetrains, such as 46/30T or 48/31T. This allows for a wider gear range better suited for off-road riding.

Tire types and sizes

When choosing between a road or gravel bike, consider the type of terrain you plan to ride on and the specific tire clearance and options of the bike you are considering.

Narrow and slick tires

Road bike tires are designed for speed.

Hence, they’re narrower to reduce weight and rolling resistance. Road racing bikes such as the Specialized Tarmac SL7 can fit tires in the 23 to 28mm range, while endurance bikes such as the Specialized Roubaix can fit 28 to 32mm wide tires.

Wide and knobby tires

Gravel tire treads range from slick to aggressive knobs to suit different riding conditions, and they are tubeless-ready, meaning they can be set up without an inner tube for a smoother ride and fewer punctures. Most gravel bikes come equipped with tubeless-ready wheels.

Gravel bikes must handle various surfaces, including pavement, dirt, and gravel. Gravel bikes have substantially more tire clearance than road bikes and can fit wider gravel-specific tires that provide traction and comfort. 

More reading : The Benefits of Using Wider Tires

Some gravel bikes are also available with 650b wheels and tires, which use a smaller diameter wheel to fit even larger, high-volume tires for the roughest roads. Wide and knobby gravel tires may be slower on pavement but provide better traction and stability on rough terrain. If needed, gravel bikes can always be set up with road tires for more speed on pavement.

It’s worth noting that genre-bending endurance road and all-road bikes are emerging that can fit much wider tires than normal road bikes. For example, the latest Trek Domane can clear massive 38mm tires, making it a great option for riders looking to split the difference between road and gravel.

More reading : How to Choose the Correct Tire Tread Patterns

Bike components

One notable difference in bike components between road and gravel bikes is the handlebars.

Road bikes typically use traditional drop handlebars, which provide low and aerodynamic riding positions for smooth pavement speed. 

In contrast, many gravel bikes use flared handlebars, which angle the drops outward and provide a wider grip for greater comfort, stability, and control when riding in the drops off-road. Traditional road handlebars have less flare, which can reduce the frontal profile of the rider and improve aerodynamics.

More reading : How to Measure Handlebar Width

In addition to handlebars, many modern gravel frames feature extra mounts on the frame to attach bags, racks, and fenders. These mounts allow riders to carry extra gear and supplies for longer rides and adventures. 

Mounts on the top tube for top tube bags and mounts on the underside of the down tube for a third bottle cage are common on gravel bikes because good resupply stops are rare on backcountry gravel roads. 

Gravel bikes designed for commuting or bikepacking also have more space in the frame for frame bags and extra mounts for bags and racks on the fork and rear triangle.

Riding comfort

It’s worth noting that riding comfort is highly subjective and can vary depending on a rider’s preferences and body type. Some riders may prefer a road bike’s stiff, efficient feel, while others may prioritize comfort and opt for a gravel or endurance bike.

While road bikes can be comfortable on regular paved roads, the limits of narrower tires and stiff frames become apparent when riding on broken pavement, dirt, and gravel. Endurance bikes are a good option for road riders seeking to enhance their comfort. 

Endurance bikes can fit wider tires. Popular models like the Specialized Roubaix and Trek Domane increase compliance with special shock-absorbing technologies added to the frames, which can provide a smoother ride on rough terrain. These technologies are similar to those found on their respective gravel counterparts.

More reading : Race vs Endurance Bikes Comparison

Gravel bikes can cope with the bumps, cracks, and rough roads common on gravel and dirt roads, and they prioritize comfort for these conditions. 

The biggest factor is the tire size, and gravel bikes use significantly wider tires that can be run at lower pressures, making them feel plusher than road bikes. Many gravel bikes also have extra compliance designed into the frame to mellow bumps and vibration.

Bike weight

Road bikes tend to weigh less than comparable gravel bikes. Road bikes are primarily ridden on smooth, paved roads, so they use narrower tires and frames that prioritize aerodynamics and weight savings. 

Gravel bikes, on the other hand, are designed to handle a wider range of terrain, including dirt, gravel, and rough roads. As a result, they use wider tires and frames that prioritize durability and stability over weight savings.

Some factors contributing to the weight difference between road and gravel bikes include;

• Tire size. Gravel bikes typically use wider tires than road bikes, which can add weight. For example, a standard road tire may weigh around 200 to 250g, while a wider gravel tire can weigh 350 to 400g or more. This may not seem significant, but the weight can add up over an entire bike.
• Frame material. Both road and gravel bikes can be made from various materials, such as aluminum, carbon fiber, or steel. However, gravel bikes may require stronger and more durable materials, such as thicker tubing or additional reinforcement, which can add weight to the bike.
• Component selection. The components, such as the brakes, derailleurs, and wheels contribute to the overall weight. Road bikes may use light components, while gravel bikes may require heavier-duty components that can handle rough terrains.

Road vs gravel bikes – A matter of suitability

In conclusion, deciding between a road and gravel bike ultimately depends on your riding preferences and the terrain you plan to traverse. It’s not about which bike is superior, but of suitability.

If speed and efficiency on smooth pavement are your top priorities, a road bike may be the better choice. However, if you’re drawn towards off-road adventures, riding on mixed terrains, and valuing stability and durability, a gravel bike is a more appropriate.

Understanding the fundamental differences in their frame geometry, drivetrain setup, tire types and sizes, components, riding comfort, and weight can greatly aid in making an informed decision that best suits your biking needs.