For most casual riders and those not participating in amateur-level competitions, V-brakes—especially decent ones—are still sufficient. Of course, for riders who enjoy downhill riding, intense cycling, or showing off, disc brakes are the more suitable choice. But you get what you pay for, and when it comes to choosing between disc brakes and V-brakes, we generally recommend that riders make their decision based on usage needs and budget.
1. First, Let’s Look at the Design Differences
Disc brakes work by using calipers (or callipers) to grip a steel disc fixed to the hub; V-brakes work by squeezing the wheel rim with V-brake calipers. In comparison, the radius of the wheel rim is much larger than that of the disc brake disc, so the braking lever arm of disc brakes is much smaller. Theoretically, this makes them less prone to locking up. Locking up is the most basic requirement for sport bike brakes, but easier locking isn’t necessarily better—unless you’re into technical cycling disciplines like trials biking where immediate lockup is required.
1.1 (Weight)
It’s worth noting that, generally speaking, low-end disc brakes are about 800g to 1kg heavier than V-brakes, with the gap narrowing for higher-end models. Listing weight separately shows that it’s an important factor that affects riding and must be considered.
2. Differences in Working Characteristics
V-brake friction occurs between a rubber compound and the wheel rim (usually the edge of an aluminum alloy rim, with low-end versions having a polished edge—so-called cut or polished edges, with cut edges being better). Generally, the braking effect is quite strong, unless you're going downhill at high speed with continuous braking. For example, when descending to the Huangma intersection, if you touch the rim with your hand, it gets very hot. At such temperatures, braking power decreases. The higher the temperature, the more significant the decline in braking effectiveness.
Disc brakes use friction between a metal disc (usually steel, though high-end ones may be aluminum) and the disc brake pads. This kind of braking is very powerful, similar to cars or high-end motorcycles. Its advantage is that it is unaffected by rain or harsh road/weather conditions because the disc brake pads are made of sintered metal. When they rub against the steel disc, even in rainy or muddy conditions, performance remains good. Although there is a noticeable drop in braking power, it is still better than the rubber-on-aluminum-rim friction of V-brakes. Additionally, since disc brake discs are made of steel and usually have holes, the performance degradation during prolonged downhill braking as heat builds up is also better than with V-brakes.
3. In Terms of Price, the So-Called Cost-Performance Ratio
For bikes priced around 1,000 yuan or 2,000 yuan, V-brakes are recommended. Almost all experienced riders say, “Low-end disc brakes aren’t as good as mid-range V-brakes.” Let’s explain this: low-end disc brakes cost between 200 and 300 yuan, including some Taiwanese brands like Assess, Promax, and even Shimano’s 475 and 495, which officially cost over 500 yuan. These disc brakes perform quite average. Among them, Shimano’s quality is slightly better, but the feel is very stiff. Usually, if a customer wants to install disc brakes, although these disc brake mountain bikes are in stock, we generally don’t recommend them—unless it’s a kid who absolutely wants to look cool but has limited money. We reluctantly sell them to those customers. We rarely recommend new riders install them. V-brakes, on the other hand, offer many brand options besides Shimano, making it easy to achieve mid-range braking performance without spending too much. For example, the classic Avid FR5 dual-pull brake lever paired with a Shimano M430 brake caliper costs just 247 yuan for the entire set, but the feel is vastly superior to the aforementioned disc brake systems. With a slightly higher budget, the same Avid FR5 brake lever can be paired with Avid’s SD7 high-end V-brake (budget brake pad version at 300 yuan, premium at 380 yuan—this is already a very high-performance V-brake), bringing the total braking system cost to just over 400 yuan. This is already a high-end braking system with no need for further upgrades. Alternatively, you could choose Avid brake levers paired with Shimano’s older LX-level V-brakes. While Shimano’s high-end V-brakes are officially expensive, the older LX models are more cost-effective here, and they offer stronger braking force. All these combinations are great. In contrast, disc brake systems at the same price point—for example, the common Shimano EF 29, EF 35, EF 50 series brake levers paired with Shimano 475 disc brakes—officially cost 680 yuan. The feel is very stiff, and after a mountain descent, your hands can get sore from gripping so hard. Many riders with such setups end up paying a lot to upgrade, which is painful.
For bikes priced between 2,000 and 3,000 yuan, installing disc brakes is a bit more manageable (though good disc brake hubs are also important, but that’s part of the drivetrain discussion). We recommend entry-level disc brakes—or so-called cost-effective disc brakes—such as Hayes’ 2004one black version, Hayes’ MX2, or Avid’s BB5. The first two cost 520 yuan and 620 yuan respectively. These products from companies specializing in disc brakes are quite solid, with acceptable feel. Granted, Avid’s BB7 disc brakes still lag behind in feel, but they are stable in quality and offer clear, responsive control. Paired with slightly better disc brake hubs, the overall bike price above 3k is ideal. Of course, even higher-end disc brakes—such as Avid’s BB7 mechanical disc brakes at a higher price point, or Shimano Deore’s 525 hydraulic disc brakes—are also good choices.
4. Summary: Practical Advice for Buying a New Bike or Upgrading the Brake System
For young people who definitely plan to ride mountain trails and have the budget, disc brakes are a good choice. If your budget is between 1k and 2k, V-brakes are more cost-effective, as your total budget is limited—why sacrifice elsewhere? If you decide early on that you’ll use disc brakes, choose the right hubs, otherwise upgrading later will be troublesome. For girls, seniors, and casual riders, V-brakes are more appropriate—they are lighter and easier to maintain. When upgrading, consider the original bike’s configuration and price as a whole. Many people say they want to spend some money to upgrade the braking system, “Just give me disc brakes!”—only to find out later that the hubs, frame, fork, and more all need to be replaced. Sigh—the cost is too high. Settling for less and spending 200 or 300 yuan on a mid-range V-brake set is actually quite good.
AVID SD3 V-Brake
[Understanding Mechanical and Hydraulic Disc Brakes]
Disc brakes on bikes have evolved from drum brakes and rim brakes to disc brakes, keeping up with the times. The use of disc brakes is becoming increasingly widespread, and this safety-critical device leaves no room for failure. Our goal is to understand disc brakes, not to judge or differentiate between good and bad. Choosing and adopting a particular system should be based on the rider's style, needs, and budget—each to their own.
Mechanical or Hydraulic (Actuated)
Based on how the disc brake operates—or rather, the medium used to actuate the brake pads to clamp the disc—there are two types: cable-actuated and hydraulic.
Mechanical disc brakes rely on the tension of the brake cable to move the pads inside the caliper to rub and clamp the disc, creating braking force. Hydraulic disc brakes use fluid as the medium: pulling the brake lever actuates pistons inside that compress the fluid, sending pressure through the hose directly to the caliper, which then pushes the pistons to clamp the pads onto the disc. Mechanical disc brakes offer compatibility advantages—standard V-brake levers can often be used. Hydraulic disc brakes, however, consist of a complete set including the lever, hose, and caliper, and share no common components with traditional cable-actuated brakes. Some disc brake manufacturers have designed semi-mechanical, semi-hydraulic systems—hybrids that retain hydraulic calipers but use cable tension to actuate a piston within the caliper. The benefit of hydraulic disc brakes is that the braking force output is several times greater than manual input, offering precise and sensitive control. They are sealed and require low maintenance. Hydraulic disc brakes are widely used in cars and motorcycles, but applying the same technology to the finicky world of bicycles involves many technical challenges—even something as seemingly simple as a bicycle is hard to perfect. However, hydraulic disc brake levers have a fluid reservoir, making them bulkier. On handlebars where space is at a premium, compatibility with STI-style shifters or grip shifters must be considered. Traditional rim brakes also had hydraulic variants—guess what? Magura HS11, 33, and 66 are examples. Cable-actuated disc brakes may lose braking power due to the cable’s length, elasticity, housing friction, and other factors. In wet or rainy conditions, disc brakes often produce squealing noises, which can be annoying to some riders.
TIP: Some people habitually store their bikes upside down. If you have hydraulic disc brakes, air or gas in the reservoir may enter the hose, affecting braking power. Get into the habit of testing your brakes before riding.
AVID BB5 Mechanical Disc Brake
AVID BB5 mechanical disc brake
Open or Closed system
There's quite a bit of debate about the internal structure of hydraulic disc brakes—let’s start with open and closed systems. The most important point is that oil expands when heated and contracts when cooled. In a hydraulic disc brake system, if the oil gets too hot—especially during prolonged braking in hot weather—it can expand excessively, pushing the brake pads outward. This may cause rubbing, dragging, or even the brakes to lock up. An open (hydraulic) system takes into account the thermal expansion and contraction of oil. Specifically, the oil reservoir at the brake lever is designed with a valve and extra space to accommodate the increased volume when the oil expands. It also allows the brake fluid to flow back, compensating for pad wear. In contrast, a closed system isolates the brake pads, pistons, and oil from external air. This prevents the oil from pushing the brake pads outward too aggressively. As a result, the oil used in closed systems must be carefully selected (typically mineral oil). Since brake pads wear down over time, closed-system disc brakes usually include an adjuster on the oil reservoir to fine-tune sensitivity.
TIP: Thinking you can fix a caliper that’s seized the rotor due to oil expansion by simply "letting out some oil" is definitely not the solution. In fact, it could put you at risk of brake failure. It’s much safer to take your bike to a shop for a proper check-up.
Mineral oil or Dot-approved (Department of Transportation) brake fluids
DOT-3 or DOT-4 are brake fluids specifically designed for automotive and motorcycle disc brakes. Their composition is meant to counteract the effects of thermal expansion and contraction. During braking, friction generates high temperatures that can cause the fluid to boil or vaporize, creating gas. The problem is that gas is much more compressible than fluid. When you pull the brake lever, you’re essentially compressing gas bubbles rather than pushing the pistons and brake pads, which can lead to brake failure or a significant loss of braking power. Additionally, DOT-3 and DOT-4 have lower boiling points than mineral oil. They are toxic and corrosive, and can even damage paint. However, they do absorb moisture, including water vapor inside the reservoir. The presence of water in the fluid lowers its boiling point. On the other hand, Cannondale’s Coda disc brake fluid is said to be a specially formulated oil developed by NASA—so it can handle the extreme heat of rocket launches, let alone bicycle braking. Magura was one of the first to use mineral oil. Its composition is very pure. While it’s non-toxic, it doesn’t absorb moisture or wash away paint. The advantage is that its braking performance doesn’t diminish over time or under high temperatures. Brake fluid should be replaced regularly. Since DOT fluids absorb moisture, it’s generally recommended to change them once a year. Mineral oil doesn’t need to be replaced as frequently, but if you notice a decrease in braking responsiveness, it’s worth checking whether it’s time for a fluid change.
TIP: The user manual or oil reservoir usually specifies which type of fluid to use. DIY enthusiasts, when changing the fluid, make sure not to mix or confuse these two types. DOT fluid can corrode the seals in a mineral oil system, and vice versa. Hayes hydraulic disc brakes use DOT fluid, while Magura systems use mineral oil.
Floating Mounting or Fixed Caliper
There are two types of disc brake calipers: those that are fixed firmly in place, and those that can move slightly after being mounted to the frame or fork—usually sliding horizontally. During the development of bicycle disc brakes, two schools of thought emerged. The design of floating calipers, which "can slide horizontally," is closely related to the drawbacks of single-sided actuation in disc brakes. However, it has its advantages. For example, frames and forks often have manufacturing tolerances, and even the thickness of paint on mounting surfaces can affect the alignment between the rotor and brake pads. This is why shims (washers/spacers) are often used to correct and align the components. Some floating calipers are specifically designed to help align the rotor and brake pads parallel and flush, without worrying about tolerances.
TIP: The paint on the disc brake mounts on frames and forks is usually scraped off during assembly because its thickness can create alignment tolerances. But be careful not to damage the metal surface, as this could make things worse.
Single-sided or Dual Actuated
Single-sided and dual actuation (or braking) aren’t exclusive to hydraulic or mechanical disc brakes, but mechanical disc brakes are mostly single-sided. In a single-sided system, only one piston pushes the brake pad against the rotor, while the other pad waits passively for the rotor to be pushed toward it, creating friction on both sides. This is also why there are differing theories about floating and fixed calipers. Dual actuation means the caliper has pistons on both sides, allowing the brake pads to grip the rotor from both sides simultaneously. Currently, disc brake calipers can have 1 piston (single-sided), 2 pistons (one pair), 4 pistons (two pairs), or even up to 6 pistons (three pairs). The number of pistons doesn’t necessarily equal the number of brake pads—for example, some designs have two pistons on one side but use a single long brake pad. Likewise, having two brake pads doesn’t always mean dual actuation, as it could be a single-sided system. For instance, the Magura Gustav M is single-sided—how many pistons and brake pads does it have? Most dual-actuated mechanical disc brakes are products of Taiwanese manufacturers, such as RST and Shimano. An example is the popular Minoura M1.
TIP: Simple test: After installing a disc brake or buying a bike with one, park the bike and pull the brake lever by hand while watching the rotor and brake pads. Observe how they come together—especially with single-sided systems, check if the rotor is being pushed too far or wobbling.
Metallic or Organic Pads
Brake pads made of different materials and compositions have varying friction coefficients.
Organic brake pads are made from materials like Kevlar mixed with glass fibers, without any metal powder. They can deliver strong braking power, but their performance drops more sharply under high temperatures and in wet conditions compared to metallic pads. The advantage is that they don’t conduct heat, so there’s less concern about the effects of oil expansion. This makes them ideal for closed hydraulic systems. Metallic brake pads, on the other hand, usually contain copper or iron powder, making them more durable and resistant to the effects of dust and mud. However, they conduct heat well, so they’re better suited for open hydraulic systems. The spacing between the rotor and both the inner and outer brake pads is typically emphasized to ensure they’re parallel and equally spaced, aiming for synchronized and balanced braking. This principle leans more toward dual-actuated calipers. Some floating, single-sided disc brakes have the rotor positioned closer to the stationary, non-moving brake pad, sometimes even lightly touching it. This means the wheel isn’t entirely free-spinning and may produce friction noises, which some say can subtly reduce speed.
TIP: New disc brakes require a break-in period for the rotor and pads. Trying to test their full power right away can be risky.
Rotor or Disc
The rotor’s main job is to endure punishment—it plays the tough guy role. Most rotors are made of stainless steel, though some manufacturers offer aluminum rotors, claiming better heat dissipation. There are also titanium and carbon rotors. Rotors must be paired with a "disc brake hub." If you want to switch from traditional rim brakes to disc brakes on a standard wheel, you’ll usually need to replace the entire wheelset or use a special adapter. Hub and rotor compatibility is another factor to consider. Standard rotors have six screw holes for mounting, though early models had four holes—Cannondale’s Coda still uses this design, as does Italy’s Formula. Hope in the UK uses five holes, but also offers a universal six-hole version. Germany’s Bees uses a non-screwed mounting system, more like a "torx" or ratchet-style, which only works with their own hubs. Rotor diameters aren’t standardized either. The most common size is 160mm, though Hope offers smaller sizes like 130mm and 145mm. Generally, more aggressive riding styles call for larger rotors, as they provide greater braking power. Typically, the front rotor is larger than the rear, or they’re the same size.
TIP: Normally, just wipe the dust off the rotor. For a more thorough clean, use alcohol. During lubrication and maintenance, avoid getting oil on the rotor—it’s the last thing you want for effective braking.
Source: Bicycle Network