Carbon fiber has become one of the most popular materials in the bicycle industry, but when it comes to choosing a wheel, you're torn between it and aluminum. Both have advantages and disadvantages in terms of material properties, but carbon fiber has become the primary high performance material for bicycle wheelsets. Why is this so, and what are the benefits and drawbacks of using carbon fiber over aluminum alloy?
Carbon fiber used in bicycle wheelsets
The use of carbon fiber in frames is now common and is considered the best choice for bicycle frame materials. However, just like frames and other components, carbon fiber is also used on top of high-performance wheelsets. But why?
Aluminum has major limitations in aerodynamic design, so carbon fiber has become the main material for wheelsets. Firstly, aluminum is not suitable for frame heights above 45mm, and secondly, carbon fiber wheelsets are lighter than the equivalent aluminum wheelsets, and will also have a very desirable stiffness-to-weight ratio.
The malleability of carbon fiber allows for more complex wheelset shapes and helps optimize the rim for better performance and significantly lower weight. This allows designers to optimize wheel shapes and structures without being limited by the lack of machining capabilities, which provides unlimited possibilities for optimal design feasibility.
When will carbon fiber become the mainstream material for making wheels?
Carbon wheels first began to appear in the early nineties, and as manufacturers began to experiment with carbon fiber materials on an ongoing basis, they made their debut on Formula 1 performance cars a decade ago.
As we see with aerodynamics today, the intersection of technology on racing, aerospace and bicycles is clear and realistic.
From Greg LeMond's victory in the 1989 Tour de France, the concept of aerodynamics began to stand out in the cycling world. Track bike pioneers Chris Boardman and Lotus then optimized aerodynamic design on their bikes.
Of course, we have a long way to go and road riders are still very cautious when it comes to adopting new technology. While high frame wheelsets are now becoming common in triathlon and road bike racing, it actually took quite a while for most of the early road riders to embrace this new technology. Cancellara won in Paris-Roubaix in 2010 on Zipp's new 303 carbon fiber aero wheelset.
What are the pros and cons on carbon fiber wheelset manufacturing?
Clearly, carbon fiber has established itself as a high performance wheelset at the top end of material choices. For wheel designers, gaining greater rigidity and weight reduction while also facilitating aerodynamic applications is beneficial but has drawbacks.
The carbon fiber lamination process involves curing the mold with carbon cloth in high pressure molding, which in many cases is still done by hand, which disguises increased manufacturing time and cost. While wheelsets can easily be produced in large numbers with a reproducible and high level of quality once the wheels have been developed and designed, the cost of production is ultimately passed on to the consumer.
What are the pros and cons of using carbon fiber wheelsets?
For the rider as well as for you, this is probably the single most important factor. The benefits of using carbon fiber for wheelsets are many, but the feeling is the same considering the cost of purchase.
Compared to aluminum, carbon fiber allows for taller, wider, and more complex wheels to improve aerodynamic efficiency, as well as the superior stiffness-to-weight ratio mentioned above.
Carbon fiber has significantly broadened the imagination of wheelset engineers. Just look at the wave profile of the Ziip 454 NSW wheels, for improved stability in side winds, to see how radical they are. Or the DT SWISS ERC 1100 Dicut wheelset, with its 47mm frame height and 27mm external width, while still keeping the weight at 1513g.
In fact, there is the most important point, which is whether the appearance is good enough and whether the style is high enough. Of course, performance is crucial, but it's undeniable that a pair of carbon fiber wheelsets on a bike looks good enough in the end, otherwise it's embarrassing to spend a lot of money and not look good.
This is not all. In addition to the high price, braking performance has always been the Achilles' heel of all-carbon wheelsets. Although all manufacturers are developing new technologies and processes to narrow the gap with aluminum wheelsets in braking performance, but there are still obvious shortcomings.
In dry conditions the carbon wheelset braking performance is quite comfortable, while in wet and especially rainy days makes you want to die, very anxious to come to a foot brake.
Like many manufacturers, DT SWISS has spent a lot of time researching the use of more advanced sizing processes and improved resins. Given that carbon fiber is typically used in aero wheels, the handling of high frame wheels is another drawback of carbon fiber wheelsets. However, this disadvantage has been gradually addressed in recent years as wheel profiles have changed. The earlier V-shaped wheels were more difficult to control when dealing with side winds, but now the smoother and more rounded, wider profile has been less susceptible to side winds.
Carbon fiber wheelsets are much more expensive to manufacture than aluminum wheels and ultimately are one of the main bottlenecks to upgrading. When you don't care about aerodynamic effects and light weight, a pair of new 1500 gram aluminum wheelsets can be under $300.
What innovations and developments have emerged in the last few years?
In contrast to aluminum, carbon fiber wheelsets have been on the market in recent years with a large number of technical improvements, some of which we have already mentioned.
The use of high-temperature resistant resins on the surface of the brake rim has improved braking and safety. These special resins are not used on the entire wheel, as this makes them more brittle and affects their impact resistance in a crash.
Similarly, advances in brake skin materials have also improved braking performance, and some wheels have adopted special textures and treatments on the brake side. Of course, the introduction of disc brakes has also had a major impact on carbon wheelsets, so that the braking performance of the brake edge has become irrelevant.
In addition, the density of carbon cloth has improved significantly over the years, so that the weight of the rim is further reduced by its increased reliability. This has led to a further increase in the manufacturing precision of carbon rims and has allowed the use of coreless molding technology.
In addition to this, as we have already mentioned, the profile design of aero wheelsets has evolved from a V shape to a U shape to improve aerodynamic performance and to face the effects of side wind blowing.
Other concepts from related fields have been borrowed in bicycle design, including the oft-mentioned National Advisory Committee (NACA) study on the best shape for aerodynamic performance. The aerodynamic design of wheelsets has evolved over several years and is now dominated by CFD (Computational Fluid Dynamics), which allows simulations to be performed for different environments, resulting in a more efficient wheelset under realistic and limited conditions.
However, in the development of carbon fiber wheelsets, the standard is always moving forward, from heat dissipation and weight reduction on the brake side to increased stiffness and epoxy composition.
So what are your options?
There are already hundreds of carbon fiber wheelsets available on the market today. However, on road bikes they can usually be divided into three main categories: low frame, medium frame and high frame. In addition, rim brake and disc brake wheelsets are now available.
In short, due to their compact, minimalist construction, low-frame wheelsets offer the lightest weight and greatest rigidity. They are also the least susceptible to side wind due to the reduced surface area.
High-frame wheelsets use more material and will therefore be heavier and less responsive on climbs, but they will have more efficient aerodynamic performance.
Once you have chosen the right wheelset frame height for you, then you also need to consider the rim profile, width, brake rim, hub spokes, open or tube tires and price to find the best carbon fiber wheelset for you.
It seems to be a bit complicated, but it doesn't matter to all of you dirtbikers anyway. Buy it and talk about it, then change it if it doesn't work...