Are Road Bikes Faster Than Mountain Bikes?
Mountain bikes make it easy to ride in rough terrains and conquer steep gradients. On the other hand, road bikes are made for smooth, paved surfaces. If you’ve not had the chance to compare the two bikes, it’s natural to wonder what the differences in features mean when it comes to speed.
Road bikes are faster than mountain bikes. They have features like drop handlebars that make them more aerodynamic. Mountain bikes sacrifice speed for better performance off-road, with features like wider, flat handlebars.
In this article, I’ll discuss the features that make some bikes faster than others. I’ll also show how road bikes have such features in abundance compared to mountain bikes. Let’s get started!
How Much Faster Are Road Bikes Compared to Mountain Bikes?
You’ll attain different speeds if you ride a road bike and a mountain bike on the same flat surface. Assuming you’re riding the typical road bike and the standard mountain bike, the road bike is likely to be faster with the same effort.
Road bikes are about 15% faster than mountain bikes on smooth surfaces. This represents a speed increase of 2-3 mph. Depending on conditions like road gradient and weight, you can be up to 6mph faster on a road bike.
If speed is the priority, you have no business riding a mountain bike. The speed gains made on a road bike are significant.
However, if you attain higher speeds on a road bike while using the same cycling effort, what causes the difference?
What Causes Speed Differences in Bikes?
It’s common knowledge that some bikes are faster than others. Differences in speed aren’t just attributed to how hard a rider pedals.
Speed differences in bikes are majorly caused by differences in the following factors:
- Aerodynamics
- Rolling resistance
In the sections below, I’ll elaborate on each factor.
Aerodynamics
Aerodynamics has to do with the air resistance a rider experiences. The more the air resistance, the slower the rider will go and the more power they’ll use to maintain the same speed.
At speeds of over 8mph (13kph), aerodynamics is the greatest determinant of speed.
As a rider, a simple way of reducing air resistance is wearing tight-fitting clothes. Baggy clothes trap more air and slow you down. On the other hand, tight-fitting clothes reduce the surface area of your frame. Consequently, you trap less air and move faster.
However, the bike you are riding has an even more significant influence on aerodynamics.
The Width of a Bike Has Some Impact on Air Resistance
The first factor is the structure of bike parts. Wide bike parts increase resistance and reduce speed. Wide handlebars have the highest negative impact on speed. When the tires are wider than the bike’s down tube, they’ll also reduce speed.
That said, the most significant factor in aerodynamics is rider position.
Rider Position Has the Greatest Impact on Aerodynamics
If you’ve seen speed racers in action, you’ve noticed that none of them rides in an upright position. They are usually bent over the handlebars, almost doubled over, and that is no coincidence.
Riding upright makes you more susceptible to air resistance because your body’s surface area is large. Air is a fluid, like water. Suppose you drag a cooking pan through water as if you are scooping the liquid and then slice through the water with a knife.
The knife takes significantly less effort.
And that’s the case with a rider on a bike.
The goal is to reduce the surface area of both the bike and the rider as much as possible. Again, think of the shape of a speed monster like the Ferrari. Such vehicles are optimized to “slice” through air.
Having said that, taking the right position as you ride your bike doesn’t just happen. You have to be comfortable. It has to feel as natural as possible. Handlebars greatly affect rider position.
Drop HandleBars and Aero Bars Make for Better Aerodynamics
Handlebars can be classified into two categories:
- Drop handlebars.
- Flat handlebars.
Flat handlebars are aerodynamically less convenient than drop handlebars. With flat handlebars, it is natural to ride while upright.
With drop handlebars, placing your hands on the downward-facing handles and leaning forward feels easy. It’s, therefore, easier to be as aerodynamically efficient as possible; to somewhat slice through the air as you ride; and to be faster.
It follows, then, that you’ll be faster on a bike with drop handlebars than on one with flat handlebars.
The comfortable forward-leaning position afforded by drop handlebars also helps improve pedaling efficiency. More power is transferred to the pedals, allowing faster speeds.
Rolling Resistance
Rolling resistance describes how hard it is for the wheels of a bike to move forward. The higher the resistance, the harder it will be to move forward and the slower that bike will be.
When rolling resistance is low, the rider is more power-efficient. More of the power they generate goes into moving the bike forward. Conversely, when there is high rolling resistance, more power is wasted.
Some of the factors affecting rolling resistance include:
- The hardness or softness of tire material.
- The mass of the bike.
- Tire pressure.
The “hardness or softness” of tire material influences rolling resistance.
Tires made of soft material have higher rolling resistance but offer better grip.
On the other hand, tires made of hard material have less rolling resistance and poorer grip. They are easier to roll and make a bike faster.
Mass also affects rolling resistance. Holding all other factors constant, if bike A is heavier than bike B, bike A will be faster.
In addition, tire pressure has some impact on rolling resistance. Tires with high pressure are firmer and deform less as they contact the ground. Since less power is wasted as the tires deform, more power goes into propelling the bike forward. Therefore, high-pressure tires make a bike faster.
Conversely, low-pressure tires increase rolling resistance because they deform more. As a result, they make the bike slower.
Why Are Road Bikes Faster Than Mountain Bikes?
Road bikes are faster than mountain bikes because they have speed-friendlier features. The narrow drop handlebars on a road bike help the rider achieve a more streamlined position. Moreover, road bikes have lower rolling resistance due to tougher tire material and higher pressure.
Below are the features that make road bikes faster:
- Narrow, drop handlebars
- Lower weight
- Hard tire material
- High tire pressure
- Gears optimized for speed
- Better frame geometry
I’ll go ahead and discuss each of the features.
Narrow, Drop Handlebars
Road bikes usually have drop handlebars – a feature meant to improve speed. The drop handlebars make it possible and comfortable for the rider to bend forward while riding. This streamlines the rider.
Since aerodynamics are a crucial determinant of speed, drop handlebars meaningfully improve the speed of a road bike.
On the other hand, mountain bikes are meant for use in rough terrain. They have flat handlebars, which gives the rider more control when navigating rough, off-road tracks.
While the flat handlebars in mountain bikes are suited for rough terrain, the rider ends up riding upright, which compromises speed.
The handlebars on mountain bikes are also typically wide, unlike the narrow handlebars on road bikes. Wide handlebars increase the surface area of the bike, making it more susceptible to air resistance. As a result, mountain bikes are slower.
Narrow handlebars reduce the effect of air resistance on the bike, making road bikes faster.
Lower Weight
The components of a mountain bike are made to withstand the bumps and shocks of off-road riding. Conversely, road bikes are built for smooth, paved surfaces like roads.
If you ride a road bike off-road, it won’t withstand degradation as well as a mountain bike.
The sturdier parts of mountain bikes make them heavier than road bikes.
Additionally, the standard mountain bike comes with suspension technology to reduce the impact of off-road shocks. Using a road bike on a bumpy trail makes for quite an uncomfortable ride. Road bikes lack the suspension technology that mountain bikes have, making the road bike lighter.
Generally, a mountain bike will be heavier than a road bike, which plays a role in the speed capabilities of both types of bikes.
The heavier a bike is, the more the gravitational pull on it and the more effort it takes to propel forward.
Thus, for the same effort, a rider will be slower on a mountain bike than on a road bike.
The standard mountain bike will be at least 12 pounds heavier than a regular road bike. This difference translates into a speed difference of at least 1 mph.
Hard Tire Material
The rubber component that makes up bike tires can significantly impact speed.
Manufacturers decide the hardness or softness of the rubber component to use on a tire depending on the bike’s intended use.
Mountain bikes are meant for off-road terrains. Successfully navigating such terrains requires tires with a firm grip, especially because riders are likely to encounter wet and slippery areas.
While the grip is a major consideration in mountain bikes, speed is a more critical consideration on road bikes. This is reflected in the choice of tire material.
Soft tire material comes with a better grip. But this is at the expense of speed. Soft tires have more rolling resistance. They are more challenging to move forward.
Mountain bike tires are usually made of soft material that affords better grip but makes the bikes slower.
Road bike tires typically have more rigid material with less rolling resistance but don’t offer as good a grip as mountain bike tires. Less rolling resistance means that road bikes are faster.
As a side note, softer tire material is usually heavier, contributing to the heavier weight of mountain bikes – though in a small way.
High Tire Pressure
Mountain bikes and road bikes have different tire pressure ratings. Mountain bikes have a pressure rating of 25 PSI (pounds per square inch). Road bikes have a pressure rating of 90 PSI.
This difference in rating can be explained by the intended use of both bikes.
High tire pressure comes with a low grip. And since the grip is essential when riding off-road, mountain bikes have a lower pressure rating. Mountain bike tires also tend to be wider. Wider tires require lower pressure.
On the other hand, road bikes have a higher pressure rating. Road bikes have narrow tires, which require higher pressure.
The high tire pressure in road bikes means less tire deformation, which means lower rolling resistance and higher speed.
Mountain bike tires have lower pressure, more deformation, higher rolling resistance, and lower speeds.
Gears Optimized for Speed
Manufacturers optimize the gears in mountain bikes for off-road action and climbing. Mountain bikes don’t have big gears.
On the contrary, road bikes have big gears, enabling a wider range of gear combinations and empowering riders to achieve high speeds. For example, road bikes ordinarily have three chainrings, compared to two chainrings in mountain bikes.
Optimizing for speed is not the priority in mountain bike gears, and this has a negative impact on speed.
Better Frame Geometry
The frame geometry of a bike is determined by its intended purpose.
With mountain bikes, the goal is to have a sturdy frame optimized for control and stability on bumpy rides. Off-road riding typically involves a lot of maneuvering, and the mountain bike is suited for that.
With road bikes, the priority is speed. Manufacturers use frames that maximize aerodynamics. The result is that it is easier for the rider to bend forward while riding and thus easier to achieve higher speeds.
The frames in road bikes also maximize pedaling efficiency. They make it easy to transfer more power from the rider to forward propulsion.
Overall, frame structure makes road bikes faster than mountain bikes.
How to Improve the Speed of Your Bike
Whether you are stuck with a mountain bike or simply want to get the most juice out of your road bike, there are some things you can do to improve your bike’s speed.
Aerodynamics is a vital factor in speed. As such, the adjustments that are most likely to make a significant impact on your speed are those that make your bike more aerodynamic.
Installing Aero Bars
One of the most effective ways is to install a set of clip-on aero bars onto your handlebar.
While road bikes already come with drop handlebars that boost aerodynamics, adding aero bars makes your bike even more effective in minimizing air resistance.
They make it comfortable for the rider to lower their body. They also position the rider’s arms inwards. The lower body and inward arm position reduce the surface area of the rider exposed to air resistance, making it possible for the rider to go faster.
Below is a YouTube video demonstrating the use of aero bars and showing how to install them:
Making Slight Changes to Your Bike’s Structure
Aerodynamics is king. In addition to major changes like installing clip-on aero bars, you can make minor changes to optimize your bike for speed further.
The first change you can make is lowering your handlebars.
The lower your head is when you are riding, the more streamlined you are. By adjusting the height of the handlebars, it is possible to optimize your bike for speed further.
Even so, you should take care not to overdo the adjustment. You don’t want to be uncomfortable while riding. If you lower the handlebars too much, there’s a chance you’ll reduce your pedaling efficiency and end up hurting your speed.
You can also improve your aerodynamics by slightly pushing the bicycle seat forward. You might have noticed that you shift forward on the seat when riding your bike in a forward-bending position. Aligning the seat’s position with your body’s automatic positioning can polish your aerodynamics.
Improving the Speed of a Mountain Bike
If you have a mountain bike, you don’t have to swap it for a road bike to get higher speeds. There are some changes you can make to boost your speed, including:
- Ditching the knobby tires for slick tires. Standard mountain bikes have knobby tires, which reduce maximum speed. You can find “road bike” tires that are smoother and fit your mountain bike rim. Swapping knobby tires for slick ones reduces rolling resistance and boosts speed.
- Locking out your suspension. Suspension is an integral part of mountain bikes. But the shock absorption results in lower power efficiency. By locking out the suspension, you can achieve higher speeds on your mountain bike. If you do this off-road, be prepared for a bumpy ride.
Conclusion
Road bikes are faster than mountain bikes, and, in this article, I’ve shown how.
Each of the factors I’ve discussed has a bearing on speed. Some elements have a higher impact than others. However, all factors combined have a significant impact. And since all favor road bikes, it’s easy to see why road bikes are faster than mountain bikes.
In a nutshell, road bikes are faster mainly because they allow for better aerodynamics and reduced rolling resistance.
Whatever you do, do not race against a road bike while you’re on a mountain bike. You’re setting yourself up for embarrassment.
