Mountain bike pioneer Gary Fisher had the right instinct back then. He was one of the first to consistently rely on 29-inch wheels and stuck with them even when 27.5-inch wheels briefly forced their way onto the scene. Today, 29-inch wheels are the undisputed standard for wheel sizes; only in a few areas do bikes still roll on 27.5-inch wheels or the so-called mullet set-up of 29-inch front and 27.5-inch rear. 29-inch wheels roll better over obstacles and offer more safety reserves on demanding trails. Super-wide fatbike wheels only play a role in the realm of the exotic - for special applications on sand or snow.
In addition to size, weight takes centre stage. Wheels and tyres are among the most effective ways to trim the bike for more propulsion. Bikes with light wheels, especially at the front, ride more lively and are easier to accelerate. However, this liveliness does not depend solely on the rotating mass, but also on how it is distributed within the wheel. External parts - especially tyres and rims - have a greater influence on acceleration behaviour than internal parts such as the hub. The lighter the wheel, the more sprint-friendly it is. This is why carbon wheels are so popular.
Carbon wheels are light and stiff
However, a carbon fibre wheelset has a second advantage: carbon is very stiff, which means that the wheels can be controlled very precisely. However, this does not mean that it is not possible to build stiff aluminium wheels. A large part of the stability depends on the spokes and the way they are laced. In practice, there is hardly any difference between good aluminium wheels and carbon wheels for the average cyclist.
The rim width also has an influence on the ride quality. Since the advent of tubeless technology, the trend has been towards wider rims. This allows tyres to be ridden with less pressure - without becoming unstable or jumping off the rim during radical cornering manoeuvres. In addition, a larger rim cross-section also improves wheel rigidity.
The carbon wheel is very popular, but it comes at a price
For many bikers, carbon wheels are the ideal complement to the carbon frames that have almost become a matter of course. Lightweight carbon fibre wheels are the object of desire for many. But quite a few are hesitant due to the high prices. The price of a complete carbon wheelset can easily be a thousand more than comparable aluminium models.
Is this investment worthwhile? Several times we have already Laboratory and practical tests put it to the test. The result: an exciting draw. On paper, carbon wheels have the edge, but the difference can be felt less clearly. The measurements in the BIKE test lab show: With an identical construction (32-hole, triple-crossed) and the same spoke tension, the carbon wheelset has a 15 to 20 per cent higher stiffness. Lateral loads are dissipated more evenly and even short load peaks, such as those that occur during rough landings, are absorbed with less deformation.
In theory, this means a more precise driving feel and greater resilience. In terms of acceleration, however, the two rivals are on the same level. In practice, the aluminium wheels also feel quite stiff. They ride almost identically. None of the testers could detect any real differences on the trails. In terms of robustness, carbon has made significant gains thanks to modern processing technologies. The only serious difference is that a bent aluminium rim can still be bent if necessary. Damage to the carbon can hardly be repaired, if at all.
Conclusion from Stefan Frey, BIKE test editor
Good wheels can be realised with both carbon and aluminium rims. Carbon definitely has the edge in ultra-lightweight construction, but then it gets expensive.
Stefan Frey
Editor
