Bike Parts & Component - Rim Material and Disc

​​Most entry to intermediate level wheels will feature aluminium rims of varying quality, while high-level wheels will typically feature rims made of carbon fibre which reduces the weight while increasing stiffness.

Rim material

Aluminium as a rim material provides better braking performance than carbon fibre, which tends to perform poorly in the wet and on long descents as heat builds up under braking. Based on this, some brands offer aluminium braking surfaces fitted to a carbon fibre rim. It’s worth noting however that these designs are typically heavier than a single-material rim.

The shift to disc brakes has well and truly begun and is quickly becoming a new norm on road bikes. Moving away from the rim and conventional calliper braking affords manufacturers some experimentation when it comes to both frame and wheel design as well as the obvious benefits of increased stopping power.

Wheelsets that use disc brakes don't need to have a brake track or confirm to a specific width in order to fit into tight fork and frame clearances. As a result, wheelsets for disc-equipped bikes can have a modified profile to improve aerodynamics and performance. The drawback is that wheelsets for disc-equipped bikes will have to be stronger to contend with the additional braking forces, meaning more spokes and specific hubs, which could potentially offset any weight saving or other performance gains. However, weight saved at the outside of the wheel (rim) has a far more noticeable impact on how light it rides than weight closer to the hub.

A huge benefit is the performance of carbon wheels, which traditionally have poor braking when compared to wheels with an aluminium brake track. Disc brakes allow for the performance benefits of carbon wheels to be maintained (or improved upon) without reducing the braking performance.

Wheels designed for use with disc brakes should not be confused with aerodynamic 'disc' wheels which form a single piece from hub to rim in the effort to reduce wind turbulence in time trial racing events.

Braking: Rim or disc

​The shift to disc brakes has well and truly begun and is quickly becoming a new norm on road bikes. Moving away from the rim and conventional calliper braking affords manufacturers some experimentation when it comes to both frame and wheel design as well as the obvious benefits of increased stopping power.

Wheelsets that use disc brakes don't need to have a brake track or confirm to a specific width in order to fit into tight fork and frame clearances. As a result, wheelsets for disc-equipped bikes can have a modified profile to improve aerodynamics and performance. The drawback is that wheelsets for disc-equipped bikes will have to be stronger to contend with the additional braking forces, meaning more spokes and specific hubs, which could potentially offset any weight saving or other performance gains. However, weight saved at the outside of the wheel (rim) has a far more noticeable impact on how light it rides than weight closer to the hub.

A huge benefit is the performance of carbon wheels, which traditionally have poor braking when compared to wheels with an aluminium brake track. Disc brakes allow for the performance benefits of carbon wheels to be maintained (or improved upon) without reducing the braking performance.

Wheels designed for use with disc brakes should not be confused with aerodynamic 'disc' wheels which form a single piece from hub to rim in the effort to reduce wind turbulence in time trial racing events.

Reference: bikeexchange.com