27.5 inch size wheel:
This wheel size is a combination of 26 inch wheel and 29 inch wheel. It improves flexibility for 29-inch wheels and also increases grip for 26-inch wheels. However, users of this type of wheel are not popular, so it is quite difficult to find ribs and components to assemble a mountain bike according to this wheel size.
29 inches size wheel:
This is the size commonly used in racing and professional terrain bikes, with topographic surfaces full of puffs, gravel roughness. 29-inch wheels ensure good grip, but in return this type of wheel has less bearing capacity and flexibility than the wheels with smaller size. This is the preferred choice of XC and Enduro riders.
- Brake system
The structure of the disc brakes consists of brake pads clinging to a rotor and attached to the center of the wheel. When the gasket pulls into the rotor, the wheel slows down because the kinetic energy is converted into thermal energy. Disc brakes are available in two versions, including a hydraulic disc brake version, which enables braking force to be stronger with less mechanical finger movement (braking), and they adjust themselves when the brake pads are worn and manual operation braking versions (mechanical) requires manual adjustment when the gasket is worn. The most outstanding advantage over Rim brakes is that it is more stable in all weather or terrain conditions, is easy to replace and does not depend on wheel size.
Rim brakes (mechanical brakes) have pads adhering to the wheel rim, operating on the principle of friction between the gasket and the wheel rim, thereby reducing wheel speed. Normally, some materials are preferred to create brake rims such as rubber, leather, .. The biggest advantage of the main brake is compact and easy to change, but the main disadvantage is easy wear and more continuous piercing than disc brakes.
Besides, there are some other popular brakes like Caliper brakes, U-Brakes brakes, Cantilever brakes …