Road biking and mountain biking are the two most prevalent cycling disciplines in the world. However, they are inherently different. This is why road and mountain bikes and their components vary in design including the wheels. But how exactly does a road wheel compare to an MTB wheel? This article explores that question to give you a good understanding of the two wheel types.
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The main purpose of road bike wheels is to be as fast and efficient as possible. Hence, compared to wheels for other types of bikes, they are usually aerodynamic, lightweight, and narrow. Conversely, mountain bike wheels are required to be strong, provide good traction and control, and be as lightweight as is achievable. Therefore, MTB wheels are wider to provide good grip, and heavier due to the rugged build.
Road vs Mountain bike wheels
Wheels for mountain and road bikes, or any other kind of bike, normally have the same structure. There is a central hub that contains bearings and the axle and is wider in a rear wheel to accommodate the cassette. For disc brake wheels, it also has an attachment for the brake’s rotor. The outer part of the wheel is called the rim, made of either aluminum or carbon. The purpose of the rim is to hold the tire. The rim and hub are connected by thin rods called spokes which are kept in tension and attached to the rim via small nuts called nipples.
Road cycling and mountain biking are two very different cycling disciplines. Therefore, the dimensions and standards vary among road wheels and MTB wheels. The table below illustrates the main differences between the two types of wheels.
|Feature||Road bike wheels||Mountain bike wheels|
|Size/Diameter||Available wheel sizes are 700c, 650c, 27.5”(650b), and 27”||Available wheel sizes are 24”, 26”, 27.5”(650b), 29”, 29”+|
|Weight||Generally lighter to reach greater speeds||Generally heavier due to sturdy build|
|Tire types||Each wheel can fit only one type - clincher, tubular, or tubeless tires||Tubeless or clincher tires. Almost all wheels are now tubeless compatible|
|Axles||Front axle options: 100×9, 100×12|
Rear axle options: 130×9, 135×12, 142×12
|Front axle options: 100×15, 100×20, 110×15, 110×20|
Rear axle options: 142×12, 148×12, 150×12, 157×12
|Rim width||Internal rim width: 15 - 25 mm||Internal rim width: 17 - 45 mm|
|Rim depth||Can range from shallow section to deep section rims. Deeper rims are heavier but more aerodynamic||Since dra is not an issue, most wheels have a shallow section to keep weight to a minimum|
|Brake types||Can have either rim brakes or disc brakes||Nearly all wheels now have disc brakes|
|Spokes||Spoke number, shape, and pattern can vary quite a bit to achieve different properties||Not much variation. Most have a high number of spokes in a three-cross pattern|
Types of road bike wheels
Road bike wheels can be broadly categorized into three types. These are climbing wheels, racing/aero/deep section wheels, and all-round/midsection wheels. In general, all road wheels come in a 700c size. Also, they should be both lightweight and aerodynamic. However, there is a trade-off between the two and so, road wheels have different designs for different purposes.
Climbing Wheels: These wheels are designed to be as light as possible. Going up a slope is when the effect of rotational mass becomes most evident. Hence, climbing wheels have a shallow section and sometimes a low number of spokes to minimize weight.
Deep Section Wheels: These are also known as aero wheels and are used for high-speed races, time trials, and triathlons. The deep rims actually make the wheels heavier, but that can cut through the air much better. And improving the aerodynamics is what achieves gains in speed and acceleration, rather than weight.
Mid Section Wheels: Having a rim section of medium depth provides a good balance between low weight and aerodynamics. These wheels are therefore ideal for all-round use, especially on flat sections and long descents.
Mountain bike wheels
Unlike road wheels, mountain bike wheels are not meant to be fast. Instead, manufacturers focus on providing strength, durability, low weight, and high traction. But as with other things in life, you can’t get all the good things at once.
Carbon rims are stiffer and lighter but more expensive than alloy ones. More spokes add more strength to a wheel but also makes it heavier. Wide rims provide better grip and lower rolling resistance but again, adds weight. Wheels with a small diameter are stronger, lighter, and more maneuverable. However, larger wheels are more stable, offer more traction, and can maintain rolling for longer. You should look for properties according to your riding style.
For cross-country racing, your wheels should be lightweight and comparatively narrower. This helps with improving speed. Downhill, gravity, and dirt-jump bike wheels are built to be robust and have high traction, with wider rims and a high spoke count. Consequently, they are quite heavy as well. If you are doing all-mountain or trail riding, then look for something in between.
Q1. Can I use road wheels on a mountain bike?
Ans.: Road bikes and mountain bikes use different sizes for their wheels. Therefore, no, you cannot just put road wheels on an MTB frame. If you want to repurpose your mountain bike for road use, there are a few ways to do so. The simplest thing to do is to increase the pressure of the tires to at least 40-50 PSI. Increase it further until it feels like they roll well. Another thing you could do is buy some slick tires, for example, 1.5” wide tires. Since gravel riding is so common now, slick tires are easy to find. They allow for even higher pressures and are aerodynamic, so you can pedal faster.
Q2. Which is best for touring, mountain bikes or road bikes?
Ans.: You can have a pleasant touring experience with either a mountain bike or a road bike if you don’t want to buy a dedicated touring bike. A mountain bike is excellent for touring on gravel roads. They have stronger wheels, especially if they are 26”, and they have a good gearing range for uphill climbs. Meanwhile, road bikes are better for road touring. They are more streamlined and have more hand positions for better comfort. The large 700c wheels allow you to maintain speed easier, but this is also possible with 29ers on a mountain bike. Think about what form of touring you will be doing and select a bike according to that.
Q3. What type of wheels are found on BMX bikes?
Ans.: BMX wheels are generally smaller and stronger than road and mountain bike wheels. The most common size is 20″, but you can find 16”, 18”, 22”, and 24” wheels as well. The rims widths are wider too with most being 32 mm wide. BMX falls into two categories – racing BMX and freestyle BMX. Racing BMX wheels require a lot of acceleration and are lighter. Freestyle BMX wheels are wider and have more spokes to ensure that they can handle all the jumps and tricks.
If you didn’t already know about the differences between mountain bike wheels and road bike wheels, then you know now. With this knowledge, you might be able to decide what kind of riding you want to get into if you haven’t chosen already. Hopefully, you will also gain an appreciation for the amount of thought and hard work put into designing these wheels.