The value of carbon bicycle wheels

 For some riders, especially racers, the charm of carbon fiber wheels is irresistible. Professional racers have been using carbon fiber wheels, and the results of wind tunnel tests show that it will save a lot of time and power. But does this mean that carbon fiber wheels are good value for money?

Carbon fiber wheels are expected to improve the strength and performance of riders. These advantages have paid a high price, but in recent years, the carbon fiber wheel market has developed rapidly, so that consumers have a new understanding of the aerodynamic performance of wheels.

Now, people want to know whether the industry will abandon aluminum for wheels like it discards aluminum frames. Twenty years ago, when carbon fiber was too expensive and unproven or even unreliable, how many drivers would foresee that carbon fiber frames would dominate?

Value for money, or pure hype?

The benefits of carbon fiber composite materials are well known, and the light weight and high strength of the material account for most of its attractiveness. Indeed, the introduction of composite rims in the 1990s provided a major leap forward in wheel design and manufacturing. The alloy rims are about 40mm high and the wheelset weighs about 2kg (1,980g), but they are considered a breakthrough in aerodynamic design. In contrast, the weight of the composite wheel is reduced by 300 grams. For two decades, the rims of carbon fiber wheels have been taller, weighing less than 1,500g (especially those with tubular rims), while light wheels have been less than 1,000g.

Carbon bicycle wheels easily reach (or even exceed) the performance of aluminum equivalent gears in terms of lateral and radial stiffness. At the same time, composite materials provide great freedom for the processing of the final product.

More and more carbon fiber wheel prices have been falling due to the proliferation of small wheel brands. These brands usually do not establish links with their own production facilities, but cooperate with low-cost Asian manufacturers to provide rims. Although these products are somewhat versatile, they usually match the weight and performance of existing brands, and outperform them on the basis of price, thereby providing consumers with more choices and market competition.

Therefore, it is fair to say that in recent years the value of carbon fiber wheel sets has increased only because of the decline in prices, but composite wheels still have many shortcomings, which every prospective buyer should consider.

Relatively limited performance improvement

The test data is clear: high-profile carbon fiber wheels have aerodynamic advantages over low-profile carbon fiber wheels, but from the bicycle and rider's point of view, these savings are small. In fact, without highly controlled conditions, these time and energy savings are often difficult to replicate.

It’s also worth pointing out that the substantial time savings promised by marketing materials for any given wheel set is calculated consistently for relatively long distances and high speeds. In addition, the reduction in resistance promised by a particular wheel set does not apply in every direction.

Therefore, the time and energy savings of any wheel set promised by any manufacturer must be regarded as a theoretically large value, and may not be completely or consistently achieved in the real world. For those buyers considering upgrading from poorly aerodynamic wheels, the speed and performance improvements will be obvious, while subtle differences between one brand and another are unlikely to appear.

With all of this in mind, unless the rider is ready to invest in complementary strategies that maximize his aerodynamic performance, it is difficult to argue the value of the marginal benefits provided by carbon fiber wheels. This includes adopting aerodynamic positions on the bicycle, paying attention to the width and pressure of the tires, investing in aviation frames, and choosing a windproof helmet.

Rim braking is a fatal injury to composite wheels

Studies have found that the braking performance of carbon rims is faster than that of standard alloy rims. However, in recent years, manufacturers have been trying to improve the braking performance of carbon fiber rims to make them close to the braking performance of alloy rims. However, overheating of the clincher may still cause delamination of the rim and/or a tire blowout after prolonged and severe braking.

The number of proprietary brake pads designed to reduce heat generation has increased, and as a result, many buyers are locked in to use specific brake pads for the carbon fiber wheels of their choice. Despite this, these new pads seem to reduce the risk of overheating, but they do not eliminate the heat generated during braking.

The heat resistance of carbon fiber rims is also helped by carefully selecting the heat-resistant resin for the brake track. However, because increasing the glass transition temperature of the rim will make the composite material more brittle and vulnerable to impact damage, this strategy can only achieve many functions.

Therefore, for carbon fiber rims, the risk of thermal damage is inevitable. In fact, the warranty provided by some brands specifically excludes thermal damage. This is not to say that composite rims are dangerous, but car owners must be prepared to adopt a cautious and mindful attitude, which is not needed when riding on aluminum alloy rims.

When carbon fiber rims are paired with disc brakes, this concern completely disappears. In fact, compared to all the work done on new brake linings and heat-resistant resins, road disc brakes and bicycles have done more to increase the attractiveness of carbon fiber wheels. Whether the increase in braking and safety is enough to make up for the extra weight of disc brakes ultimately depends on the needs of the rider, but it is easy to see that carbon fiber rims will become the standard choice for road disc bicycles.

How strong and durable?

After more than two decades of manufacturing, people’s concerns about the strength of carbon fiber composite materials for vehicle frames have decreased. Similarly, people's confidence in carbon fiber wheels is increasing. Nevertheless, carbon fiber composite materials are still susceptible to impact damage, so car owners should be aware that repairs can be expensive in the event of a crash or potholes that damage the rim. This may be a major disadvantage of carbon fiber composite materials-not only the purchase cost is high, but also the maintenance and replacement costs.

Although cost is considered, it is surprising that some MTB riders, including downhill riders, have begun to use carbon fiber rims. This is enough to show that carbon fiber wheels are not only attractive to racers with aerodynamic requirements, but also can Attract other riders.

Although it is expected to achieve higher strength and durability, each composite product has the risk of manufacturing defects, which are related to voids generated in the manufacturing process. These defects are invisible to the naked eye, but they can have a profound impact on the life of the product.

Similarly, impact can produce substructure delamination that is almost invisible except for ultrasound and X-ray inspection. Therefore, seemingly harmless collisions or collisions may damage the rim until later failure.

The carbon fiber bicycle wheel market is expanding

The carbon fiber wheel market follows the same trend as carbon fiber bicycles, because over time, low-cost alternatives to new brands gradually appear instead of market leaders lowering prices. As mentioned above, the increase in production in Asia provides consumers with cheaper carbon fiber wheels, but most carbon fiber wheels are designed to compete with more expensive brands.