A Guide To Carbon MTB Rims

Are you curious what all the fuss is about carbon MTB rims? In our guide to carbon MTB rims, we give you the low down about carbon rims, what to look for and how they compare to the more traditional aluminium rims.

Your wheels or rims are the most important part of your bike. They are the only contact between you and the ground and your rims have a direct effect on your speed, performance, safety and comfort.

So if you’re thinking of upgrading to carbon rims, or are just curious about them, keep on reading for all the info you need.

What Is Carbon Fibre?

Carbon fibre is a composite material which consists of strong, thin crystalline strands of actual carbon. These strands are composed of carbon atoms which bond together to form a long chain. This formation makes carbon fibre exceptionally stiff, light and strong, which also makes it extremely versatile for making almost anything stronger and lighter.

Carbon in its raw state is very versatile as it comes in various forms including yarns, uni-directional fabrics, weaves and braids, which are then used to create carbon fibre composite parts.

The benefits of carbon include the following:

increased stiffness
high tensile strength
a low weight-to-strength ratio
high-temperature tolerance
low thermal expansion and contraction
high chemical resistance

Carbon vs Aluminium MTB Rims

If you are looking to upgrade your bike then your wheels are a good place to start. A good quality wheelset can increase the performance of even the most basic entry-level bike. They can help to reduce weight, increase stiffness, improve tire support and boost aerodynamics.

Traditionally, high-grade aluminium has been used, but nowadays (if the budget can stretch that far) carbon has become the wheel of choice.

When used to make bicycle rims, a carbon fibre wheel is often much lighter and stiffer than a comparable aluminium wheel. The combination of low weight and increased stiffness contributes to improving your bike's acceleration and handling. This makes carbon the most popular option for cyclists who race, or for just about anyone who cares about increasing their performance.

Carbon Pros	Carbon Cons
Lower weight	Expensive
Extra stiffness	Needs replacing when damaged
Better aerodynamics

Aluminium Pros	Aluminium Cons
More affordable	Slighty heavier
Longer lasting/repairable	Less stiff
More comfortable

What To Look For In Carbon MTB Rims

So if you’re ready to take the next step in cycling and are looking to upgrade your wheel-set to carbon, the most difficult decision will be to choose the most suitable carbon wheel-set for you. There’s a lot of choice out there. A significant factor for many cyclists is selecting the right wheel depth to meet their needs as a cyclist.

While carbon is lighter than its aluminium counterparts, the depth of the rim is what matters most. The depth of carbon rims is measured in millimetres. Most spoked carbon rims are between 30mm and 90mm deep. Deeper rims are typically associated with improved aerodynamics. This is because a deep rim produces more side force. Side force can be thought of as lift on an aeroplane wing or how the air pushes the sail on a boat. In modern times, we’ve learned that to improve aerodynamics you need a balance of width and depth around a specific tire profile. Finding the right combination of width and depth produces a faster and more stable wheel.

In addition, any carbon rim will work as long as it’s the right diameter. Simply put, you can’t go wrong with a carbon rim as long as the diameter is right. However, at lower speeds, the depth is not so important. But, if you’re a triathlon rider or a sprinter then anything that contributes to your aerodynamics, like the depth of the rim, can increase your speed.

Our best tip, when deciding to upgrade to carbon, is to consider the type of rider you are plus your style and level of experience. In addition, it’s important to consider where you spend the majority of your time riding and what type of terrain that includes.

How Your Riding Style Affects Your Carbon MTB Rim Choice

Although carbon has come a long way during its relatively short history of manufacturing bicycle wheels, it still has a reputation for being brittle. So if you are an aggressive downhill rider then carbon rims may not be the right choice for you.

Unfortunately, with mountain biking, wheels are very prone to damage. Wheel damage is especially common for downhill and enduro riders who attack tough off-road trails at high speed. This type of riding generates more energy which can make rim or wheel damage more likely. Aluminium rims are more affordable, so many riders can easily accept the replacement cost as part of the sport. But the high cost of carbon rims can turn people off when they experience a similar failure.

As a general piece of advice, you should ride wheels that you can afford to replace. For many MTB riders, that means aluminium. However, some manufacturers are offering generous carbon rim warranties that offer easy, no-questions-asked rim replacement for the original owner. This guarantee has the potential to offset the initial cost of a carbon wheelset.

Some Iconic Carbon MTB Rim Makers Throughout History

Carbon MTB rim manufacturers have a relatively short history - the first carbon wheel was only introduced in a race in 1993.

Back then, Heinz Obermayer and Rudolf Dierl developed a carbon-spoked wheel, which immediately received UCI certification for pro-competition at its launch in 1994. However, it wasn’t until 1998 that the first clincher rim was introduced by Lew Composites. The owner, Paul Lew, was a keen triathlete who wanted the same weight savings and aerodynamics that a carbon tubular could offer, but with the ease and versatility of a clincher tyre. And that is how the popularity of carbon rims began.

Other popular carbon rim manufacturers include the following: