Popular science of road bike disc brakes .
The trend of using disc brakes on road vehicles has gradually transitioned from the controversy in previous years to the current trend. Stronger braking force, more stable wheel fixation methods, and technological progress have reduced the weight of the kit, which has led to the mass promotion of disc brake road bikes, and some major manufacturers have radically eliminated the rim brakes when launching new models. type. There are many ways to install and drive disc brakes. Let's take a look at the popular science, so that more riders have a clear understanding, and there are materials to refer to when upgrading or choosing their bicycles in the future.
Disc brakes are distinguished according to the driving mode, which can be divided into: hydraulic drive, wire pull drive, and wire pull hydraulic drive.
1. Hydraulic drive
The principle is to use oil as the medium, compress the oil through the piston in the brake lever, and transmit the pressure to the caliper through the oil to rub the discs to act as a brake. This is what people often call "oil discs"; generally speaking, the oil pipes of hydraulic disc brakes are not affected by bending. Even if the oil pipes are folded to a more complicated angle, they can still provide excellent braking force. Most of the road models of the line choose hydraulic disc brakes. On the other hand, because hydraulic disc brakes must first ensure the sealing properties when using oily objects for transmission, hydraulic disc brakes have less force loss during transmission, and the force is direct, so gently pinch it down It can provide powerful braking force, which is also one of the biggest advantages of hydraulic disc brakes. At the same time, because of its closed system, the inside of the tubing is not invaded by dust, and the maintenance period is long.
Compared with the advantages of hydraulic disc brakes, the comprehensive promotion of hydraulic disc brakes shows that its shortcomings can be almost ignored in daily use. The most important disadvantage is that on the one hand, there is not much advantage in weight, on the other hand, it is more troublesome to install and replace, especially in the application of inner wiring frame, which requires disassembly and oil filling, which greatly increases the working time.
2. Wire pull drive
This is what people often call the "cable disc". The brake pads in the caliper move by the pull of the brake wire to rub the discs to produce a braking effect. Cable discs have greater advantages in weight and maintainability, and they are usually cheaper than oil discs of the same grade. This is one of the reasons why low-end disc brakes will choose cable discs. On the other hand, when using the cable disc to upgrade from the clamper model, there is no need to change the hand change. However, because of the need for brake cables, the wiring of the cable tube cannot be bent significantly. When the fully hidden wiring method is now an advanced choice, the cable disc is almost invisible in the selection of high-end models; At the same time, the braking force of the cable disc is less than that of the oil disc, which makes many riders less confident when going downhill, and makes the film more difficult to adjust than the oil disc, and the probability of rubbing the disc is greatly increased.
3.wire pulling to hydraulic drive
The development of this product was made in the early stage to make up for the delay in the development of the hydraulic manual transmission by the transmission kit manufacturers. It is also aimed at many people who want to upgrade the disc brakes but do not want to replace the manual transmission, or want to neutralize the cumbersome installation of hydraulic disc brakes. A balanced product made with heavier weight.
Its basic principle can be divided into a cable pull cylinder, which is directly pulled through the cylinder to connect the caliper or the brake cable. The former was used on the Giant model and has now been eliminated. The latter is currently the mainstream method of line-to-oil disc brakes. This design is close to hydraulic drive in terms of braking force, and is relatively low in weight and price, and easier to maintain. The disadvantage is that it still can't adapt to the full internal wiring design, and wiring needs to be considered.
According to the installation method, it can be divided into: flat clamp, direct clamp. For disc brake calipers, the early disc brake mounts used the direct mounting standard of mountain bikes, which can be directly installed on the frame without a conversion seat. Then Shimano introduced the flat mount caliper standard, which has been adopted by most frames. Used by vendors and kit vendors.
Compared with the paperback specification, the size is smaller, lighter, and more beautiful. It is undoubtedly a good solution when road bikes are very sensitive to weight. The interface of the flat mount clamp is more compact, which is conducive to the integration with the front fork. The biggest difference is that the screw is directly screwed into the clamp from below and fixed from the frame. In addition to the screw tightening method, the clamp has other structures such as oil pipes and pistons. The structure and so on are the same as direct mounting.
The early clamps adopted the design of mountain bikes. Two fixing screws passed through the clamps from above and fixed to the frame or front fork. Due to the different sizes of discs, large adapters were often needed. Increased weight and reduced aesthetics. Due to the small selection of disc diameters on road vehicles, the importance of this wide-range adjustable design has been reduced and gradually replaced by plain packaging.